960 Strange Problem (Timing? Carb?)

I need help. My 960 has run terrific this year. I rebuilt the hydraulic pump last winter and put in a new pressure valve, adjusted everything in the hydraulics.

Three weeks ago I notice the hydraulics acting flaky. Slow lift, jerky. So I"m revving the engine to get it to lift faster, but then it stops lifting at all. I throttle the engine back down, and it starts sounding like a sick calf. ???

The hydraulic problem was easy to fix - the pump bolts had worked loose and it lost prime. Fixed that. But I can"t figure out what happened to the engine. Here"s what I"ve tried:
- Carb rebuild
- Compression check (all around 150)
- air intake checked for obstructions (nothing)
- exhaust checked for the same (nothing)
- bubbles in radiator? (nothing)
- plugs replaced with new gapped plugs
- new wires
- new coil
- took out distributor and found nothing wrong with it (more on this in a bit)

So I think it"s timing/ignition, but I"m not sure. I can get it to start, but it"s hard. All the plugs spark fine. Sometimes I can get it to run completely normally, but only for about 5 minutes, then it chokes back to the sick calf mode. When it"s running, I"ve set the carb screws to make sure that"s not a problem. When it gets in sick mode, I can sometimes manually change the timing (turn distributor) and get it to run again, sometimes I can"t. How warmed up it is doesn"t seem to make a difference. I don"t think there"s anything wrong with the gas either. It was empty today so I gave it 5 gallons of fresh gas, no difference.

When I worked on the distributor, I cleaned a bit of carbon off the posts & the end of the rotor. Someone suggested a bad condenser, but I found out this distributor has a Pertronix Ignitor ignition. So nothing to adjust there. I checked the distributor advance weights and gave them a little lube, but they seemed fine.

I couldn"t actually set the timing properly. I borrowed a timing light today, and couldn"t find the timing marks on the flywheel. Hand turned it the whole way round twice and couldn"t find them. But the timing light worked fine. I even tried it on the other plug wires and it worked on all of them.

Any ideas?

The timing marks can be hard to see when they're covered with clutch dust, grime, etc. Put some solvent on a rag and stick it in the hole so it rubs on the flywheel and turn it. You can narrow down the search by first getting #1 piston at TDC. It doesn't matter whether it's on compression or exhaust- the timing marks will be in the window.

Yeah, did that. Held a GoJo wipe against the flywheel where the marks were supposed to be. Actually, I had a helper wiping it off while I turned the crank from that big bolt in front. The *first* thing I did was pull the cylinder 1 plug and find the point where the distributor rotor was pointing when it compressed. An "O" on the dust cap, in our case. We went by that spot three times trying to find the timing marks. We started just before it, and ended just after it after two complete turns around.

We spent a lot of time on pages 91 and 101 of the FoMoCo shop manual, trying to figure out if we were missing a timing adjustment or carb adjustment.

Hold a piece of chalk against the flywheel and turn it. Sometime that helps find the mark.

(quoted from post at 22:31:25 10/06/13) Hold a piece of chalk against the flywheel and turn it. Sometime that helps find the mark.

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e has already confirmed that timing is NOT his problem when he said, " Sometimes[u:2feff78b41] I can get it to run completely normally[/u:2feff78b41], but only for about 5 minutes, then it chokes back to the sick calf mode.".

(quoted from post at 00:08:54 10/07/13)

(quoted from post at 22:31:25 10/06/13) Hold a piece of chalk against the flywheel and turn it. Sometime that helps find the mark.

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e has already confirmed that timing is NOT his problem when he said, " Sometimes[u:a408183788] I can get it to run completely normally[/u:a408183788], but only for about 5 minutes, then it chokes back to the sick calf mode.".

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Ditto...sounds like a fuel flow/restriction problem. Check flow from line to carb. Is it steady and good flow? If so, junk in the carb somewhere.

Could also be junk in the tank getting sucked up against the screen.

Start diagnosing fuel issue, starting with the basics.

Well, fuel flows freely when I loosen up the sediment bowl. And the screen there is clear. I also took off the air intake hose and sprayed some starting fluid in there, just yesterday, which didn't change a thing (except that it spit some of the fluid right back out - sometimes it's backfiring through the carb, sometimes through the exhaust).

Is there another screen in the fuel tank? I didn't see one up there.

The carb itself was completely clean when I worked on it. Carb cleaner sprayed through all of the passages and it flowed, fine wire through the jets and they were all clear, replaced the parts that were in the kit.

And why does changing the timing sometimes get it to rev back up again if it's not getting fuel?

Some other tests that I did, now that I think of it. Last week when it was running really weak, I tried taking the plug hoods off one at a time. Every time I did, it got even weaker, and got better when I put the plug hood back on.

Like I mentioned, I sprayed some starting fluid into the air intake for the carb, and it didn't change anything. And sometimes it backfires through the exhaust and sometimes through the carb, but those may be because I've been changing the timing.

It hasn't been using much oil or coolant either, though sometimes while it's been having this problem it blows extra black smoke out the exhaust.

The odd times it's running well, I can throttle it down to idle and up to 1500 rpm pretty smoothly. (For some reason I don't understand, I've never been able to get it much above 1500 rpm on the proofmeter, but I don't need it higher so I haven't worried about it.) When it's running weak, I can put the throttle anywhere from 1/4 to full and it just barely chugs along, but throttling all the way down kills it.

If so, junk in the carb somewhere.

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Yeah, I do want to open up the carb again and see if I can find anything else in there. I just have my doubts I'll find anything there.

I'm wondering if those ignitor ignition things sometimes go bad, or if I could have some kind of weird intake valve problem. I haven't done a vacuum test (can't figure out where there's a test port!) or taken off the valve cover to make sure the valves are moving like they should. I haven't done a valve lash adjustment in a few years (I only use the tractor once a week).

I also haven't tried taking out a plug when it's running bad and verifying the spark then. Seems risky pulling a plug out of a running engine.

if it -ever- runs good.. it's not timing. check fuel next.

choke help any?

When I'm starting, the choke doesn't help that much, though of the ten or twelve times I've gotten it to fire back up some, one time the choke *had* to be out to keep it running. All the other times it just kills it off.

But on my tractor the choke has always been about useless. It usually starts up just fine without it, and the choke never seems to help starting it. In the past if it didn't start right up, it was either because I hadn't turned the key yet or I gave it just a little throttle and it started right up.

The part that I don't get though is that when it's running weak, the thing that helps to get it to run well again is to get off, pull the 1/2" wrench out of my pocket, loosen the two distributor bolts, and rotate the distributor a bit. If I turn it counter-clockwise (oiler toward the front), it starts to rev a bit better, but then starts to miss. If I rotate it back clockwise (oiler toward the back), it hits on every cylinder, but gets weaker.

What sometimes works is to rotate it counter-clockwise a bit, wait 10 or 20seconds or so till it revs back up, then back it to about where it was and lock it back down. It was a bunch of those times, when it was running normally again, that I checked the carb screws again to adjust them like the book says. When it's running OK, the carb adjustments do just what the book says they will. When it's running weak, the adjustment screws don't do anything unless I screw them all the way in, which kills the engine.

It really seems like it's getting plenty of fuel, or even too much sometimes, but not firing it well. I wonder about that Pertronix thing...

(quoted from post at 11:45:06 10/07/13) When I'm starting, the choke doesn't help that much, though of the ten or twelve times I've gotten it to fire back up some, one time the choke *had* to be out to keep it running. All the other times it just kills it off.

But on my tractor the choke has always been about useless. It usually starts up just fine without it, and the choke never seems to help starting it. In the past if it didn't start right up, it was either because I hadn't turned the key yet or I gave it just a little throttle and it started right up.

The part that I don't get though is that when it's running weak, the thing that helps to get it to run well again is to get off, pull the 1/2" wrench out of my pocket, loosen the two distributor bolts, and rotate the distributor a bit. If I turn it counter-clockwise (oiler toward the front), it starts to rev a bit better, but then starts to miss. If I rotate it back clockwise (oiler toward the back), it hits on every cylinder, but gets weaker.

What sometimes works is to rotate it counter-clockwise a bit, wait 10 or 20seconds or so till it revs back up, then back it to about where it was and lock it back down. It was a bunch of those times, when it was running normally again, that I checked the carb screws again to adjust them like the book says. When it's running OK, the carb adjustments do just what the book says they will. When it's running weak, the adjustment screws don't do anything unless I screw them all the way in, which kills the engine.

It really seems like it's getting plenty of fuel, or even too much sometimes, but not firing it well. I wonder about that Pertronix thing...

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might have missed it, but I don't see where you checked manifold to engine & manifold to carb for vacuum leaks. New gasket between carb bowl & body?

(quoted from post at 17:37:34 10/07/13) I might have missed it, but I don't see where you checked manifold to engine & manifold to carb for vacuum leaks. New gasket between carb bowl & body?

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You're right, haven't checked those yet. How would you do those checks? I'd usually spray some starting fluid on those areas or maybe some propane and listen for the engine to rev up. But spraying starting fluid right into the carb air intake didn't do anything. Is there a vacuum port somewhere?

No, there wasn't a new gasket for the sediment bowl in that carb rebuild kit. I need to get one.

I prefer propane, but starting fluid will work, too. No port for vacuum connection. Bowl to body gasket can result in air leaks, carb bowl pressure problems & intermittent operation as small leaks are often temporarily sealed by sloshing gas.

(quoted from post at 18:05:05 10/07/13) I prefer propane, but starting fluid will work, too. No port for vacuum connection. Bowl to body gasket can result in air leaks, carb bowl pressure problems & intermittent operation as small leaks are often temporarily sealed by sloshing gas.

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OK, I'll try the propane. Looks like Tractor Supply carries those gaskets, so I'll pick one up on my way too. That'll be on Wednesday.

& BTW, since I was apparently asleep when I started this thread, I have an [b:54ec8fde3e]860[/b:54ec8fde3e], not a [i:54ec8fde3e]960[/i:54ec8fde3e].

(quoted from post at 18:05:05 10/07/13) I prefer propane, but starting fluid will work, too. No port for vacuum connection. Bowl to body gasket can result in air leaks, carb bowl pressure problems & intermittent operation as small leaks are often temporarily sealed by sloshing gas.

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OK, had a chance to check things today. I replaced the bowl gasket, but it didn't seem to make a difference - more on this in a bit. I also shot propane at all of the manifold/engine and manifold/carb gasket areas. That didn't seem to change anything either, but more in this too. Finally, I used Sunbeam's trick and used chalk against the flywheel. Aha! Timing marks. And not on the part of the flywheel shown in my manual either. But I did manage to check the timing, and it's about right now.

On the sediment bowl, I put the new gasket in, sealed it back up, and at first the tractor started hard, but then slowly came up to normal. That's pretty common while it's having a problem, and a bit later, it went back to Model T mode (I decided that's a better description of what it sounds like.) But this time, I looked up through the bowl to the top to see what it looked like. At first, I saw a small bit of bubble below the screen, but mostly screen. When it was running weakly again, it was almost all bubble under the screen, and I even saw some bubbles coming out of the port the gas comes through from the fuel line.

So I checked the fuel line. First I took a look into the gas tank. Sure enough, there *is* a screen up there too, but I didn't see anything in the screen. Gas was a bit low, so I added 10 gallons, including five that was about two weeks old and five that was about 3 days from the station. Next I shut off the fuel line, and disconnected it from the bowl. Put a quart cup under it and went around the other side and opened the shut off again. Fuel poured out, probably about a pint a minute or so. I only let it go about 30 seconds and it about 1/3 filled my cup.

On the propane test, when it was running weakly, I got my propane torch out, took off the mixing head, and opened the valve. I verified I had a nice jet of propane, and pointed that jet at all of the gasket areas, about an inch away from them. No real change anywhere I could find. But right there in front of my face was a screw someone told me about, right above the carb. Looks like what I'm suppose to use to check vacuum. I tried taking it out, and the engine perked up a bit. Didn't run right, but ran better. I put it back in and it ran weakly again.

I shut the engine off, and checked bolts. Two of the manifold bolts, near cylinder 4, needed a bit of tightening. One of the carb bolts wasn't as tight as I thought too. I tightened all of them up, but there wasn't any difference when I started it back up.

One more thing I tried on the carb - there's a screw that goes in at the upper-left, where the fuel comes into the carb from the bowl. That was seized enough I was afraid of stripping it, so I hadn't touched it. Today I hit it with some PB Blaster and managed to work it out. It does seem like a kind of priming screw for the carb, since it took a while for the fuel to come out of that hole. But putting it back in afterward didn't seem to improve the way the tractor ran.

But, after all of that I was able to nurse it along for a while today. As long as I kept the rpm down, it seemed to be able to go for a while like that. If I revved it up, it would rise decently for a while, but then start dropping. If I dropped it to idle then, I could keep it running for a while. That does seem more like a fuel-starving problem.

Before I left, I pulled the carb to make sure I didn't get more gunk in a jet and see if I missed anything. I also pulled that screw above the carb, so I can make a fitting for my vacuum gauge that will fit in that screw hole.

Oh, yeah, one more thing. I took off the valve cover and watched for problems. Nothing wrong there. I might need to do some adjusting, but everything moved like I expected. So I don't think I have a valve-not-opening problem. No one mentioned that, but I thought I would check.

The mystery screw that you speak of......is it similar to the hex plug here?

Sorry for the late reply. That's funny, on my carb, it's a screw, like on your manifold. But on my manifold, its a hex bolt, like on your carb. I wonder if they're the same size/thread.

Yeah, that's the screw/bolt I was talking about. I have lots of updates though. So first, having finally gotten a clue, I managed to do two vacuum tests. The first one is attached (I think). That's the one for when the engine is running pretty well.

Well, *that* didn't work. Here's the video @ youtube: http://youtu.be/F1wnCWz1pYA.

I'm not really vouching for my vacuum gauge. It's reading 11in of vacuum, but it might be more than that. But it's pretty steady at idle. (I did warm up the engine first.) As I throttle up, vacuum drops until I leave it somewhere, then vacuum increases to a steady reading of 10/11. If I throttle it way up, it settles at less vacuum, but I think that's normal. However, one time I throttled it up, it got to 1300rpm or so, settled, then started falling. The vacuum dropped as the engine was revving up, settled around 10, then started falling along with the engine speed.

OK, so here's the next video. This is when the engine is running really weakly. We used the tractor for a while when it was running, and after about 20 minutes, it was barely running again. I let it cool down, then started it back up. I decided to slap the vacuum gauge back on at this point.

http://youtu.be/YOwNjQVUZOQ

The sound isn't great on these, but the first one is how things are supposed to sound, and the second one is barely running. You can see the difference in the vacuum gauge this time. Vacuum's about 5in wobbling to 4 or so. Never gets up to a reasonable range. Sorry that the gauge is up-side down for both videos.

Not being there, it is impossible to know what you are doing with throttle relative to gauge movement, but you may be able to relate it to this info.
http://www.secondchancegarage.com/public/186.cfm

Two more notes. First, my hydraulic pump is also shot. It was making some funny noises, so I pulled it off and opened it up and found something out of Nightmare on Elm street. Broken springs, mashed pistons, mangled wobble shaft bearing plate. Ouch. I don't think it's related to these problems, but I thought I should mention it. I ran it today with most of its guts removed, and the tractor didn't run any different.

The carb on the other hand, might be important. So after running into a brick wall earlier this week, I pulled the carb and took that home too. This time I found some problems I'd missed last time. Most important was at the bottom of the fuel bowl. There are two screws down there. One is a good-sized bolt, the other is a teeny little screw. I think the bigger one is to drain the fuel bowl in case you get water in there. That bolt is seized hard. I tried PB Blaster, ended up half stripping the bolt head, so I filed it back to a reasonable shape and hit it with my torch. That didn't work either, so I gave up on getting it out. I bet it hasn't moved in 20 years, long before I got the tractor.

The smaller one comes out just fine, and sits at the bottom of the fuel accelerating well. At least, it does on mine. I don't think it's supposed to, though. I ended up picking out a good bit of rust out of there, where water had gotten in at some point and never got drained and rusted out the bottom of that well. I suspect that this makes my main adjustment needle useless. The needle sure doesn't seem to work very well. Fuel is probably just bypassing that opening and flowing up into the accelerating well as fast as it wants.

That's about half my problem isn't it? Sure seems like it's time for a new carb. But that doesn't explain the vacuum funniness, does it? Or is this just an engine running so rich it can barely catch a breath?

Not sure what model carb that you have. Where is main power adjust located? Probably TSX-593 or TSX-706 with power adjuster on top (throttle body instead of bowl). If so, then the adjust needle should seat in a brass part in the bowl of carb. Inspect that seat.

Here's a breakdown of what I was doing when:
0 - :20 - Idle
:21 - :35 - increase throttle from idle to 600 (~:24), 1000 (~:30), 1200 (~:33)

:36 - :45 - full throttle, ~1500rpm.

:46 - 1:00 back to idle

1:01 - 1:25 - ramp back to full throttle. I also looked at the sediment bowl in here, thought it's hard to see in the video why. I was getting small bubbles shooting down out of the fuel line at that point.

1:26 - end - back to idle.

Thanks for the link! Of those, I think I might have #4 and maybe #14 (the banana-in-the-tailpipe). I was backing our scoop into compost earlier the day this all started. But it seems to be blowing exhaust out with plenty of force. Dunno. #4 doesn't really fit, but it does show lower vacuum, a significant drop on acceleration, but an increase on dropping the throttle, which I don't really get when I drop it back to idle.

KJMCLARK,
I believe if you think this through you will see a cause for your problem.
My logic is this. You worked on the hydraulic pump last year. It was OK then. Then the pump starts to act up and while that is happening the motor suddenly starts to run bad.
You look at the pump and the insides of it are bent and twisted.
Have you considered that the Hydraulic pump is driven off the end of the cam shaft. That cam shaft also drives the distributor.
To me, the force need to bend and break parts inside that pump may well have bent or brokened other parts in that drive line.
Possible areas of damage are the gears that drive the cam on the front of the motor and the gears on the back of the cam that drive the pump.
HTH
Keith

KJMCLARK,
I believe if you think this through you will see a cause for your problem.
My logic is this. You worked on the hydraulic pump last year. It was OK then. Then the pump starts to act up and while that is happening the motor suddenly starts to run bad.
You look at the pump and the insides of it are bent and twisted.
Have you considered that the Hydraulic pump is driven off the end of the cam shaft. That cam shaft also drives the distributor.
To me, the force need to bend and break parts inside that pump may well have bent or brokened other parts in that drive line.
Possible areas of damage are the gears that drive the cam on the front of the motor and the gears on the back of the cam that drive the pump.
HTH
Keith

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Well, I guess I'd say "I don't think so", and "I hope not". If I don't get things working soon I'm going to have to give up and put it in a shop. It's just a $300 tow to even get it to the shop, so I'm hoping to figure it out myself.

And nothing is really bent inside the pump, except for some pretty weak parts. Some springs were bent/broken, and the bearing race for the wobble plate was broken (bearings were facing every which way in there.) The worst thing was that the face of the wobble plate was torn up a bit, the pistons had their faces mangled a bit, and some of the pistons didn't travel in their sleeves very well. I had to do some work on the pistons to get them moving smoothly again, and resurface the wobble plate and piston heads.

An update. I put on the new Zenith carburetor, and [i:03664cd879][b:03664cd879]tried[/b:03664cd879][/i:03664cd879] to hook up the sediment bowl. Everything else went well, but the sediment bowl smacks into the drain bolt for the new carb, and I can't screw them together properly. The best I was able to do is stick three washers onto the end of the banjo bolt and tighten things up a bit. It wasn't a very good connection, and fuel definitely leaked. I need to work out something better. JMOR's picture shows a narrower/longer sediment bowl, and I'm thinking I might need to switch to that.

OTOH, the engine ran a good deal better. Not great yet, but it kind of actually ran. I think the plugs are so fouled that I need to replace them. I was going to clean and gap them, but my manager pointed out that carbon deposits on the insulator will leak charge, so I should just swap them out. I have another new set that I'll try this weekend.

Last thing is the hydraulic pump. I drained the tank, pulled off the relief valve, the manifold from the body to the pump, took off the top cover, and got out every chunk of metal I could find. I ran a magnet pickup through the lines as best I could to get chunks out of there too. Then I put it all back together, put on the rebuilt pump, put in hydraulic fluid, tried to lift the 3pt, and - nothing. Crud. Opened the priming plugs and saw almost nothing going on in there. I pumped a bunch of fluid into both plugs, both with the engine running and when it was stopped, but nothing seemed to make a difference.

Talked to my boss about it again (he's an engineer and thinks this stuff is cool), and he thought it sounded like the check valves were letting fluid/air back past the seats. I called up Walt's Tractors, where I bought one of the rebuild kits, and talked to one of their gurus. He pointed out that the check-valve seats are supposed to fit tightly, and that often people just drop them in not realizing that the old ones are still in there. They're just hard to spot because they're so worn down. I bet that's what I did, and I'll need to open that pump back up again.[b:03664cd879][/b:03664cd879]

Anyone still around? New question for the same problem. On my manifold, there are six bolts (same as everyone's, I'm sure.) Under the second and fifth bolts, the ones between the intake and outermost exhaust ports there are expansion joints. Or that's what I've been assuming they were. Expansion joints, also known as great, big, straight cracks from top to bottom under those bolts.

Are those supposed to be there? I tried blowing starting fluid into those to see if there was a vacuum leak there, but got no change. Of course, that's right next to a hot exhaust port, so that might evaporate any starting fluid before it could get into an intake problem. Big problem cracks, or normal expansion joints?

I got hung up on when you took out the screw on the manifold, it ran faster and better.. meaning your carb was flooding badly.. but now you have a new carb and should be past that.



secondly.. crap in hydraulics. means that you need to pull the pump off, and the rear cyl off and clean everything.. as the gunk is everywhere in the system and lines... don't worry about bottom of sump, just the lines, pump and hyd valves under the cover.

I got hung up on when you took out the screw on the manifold, it ran faster and better.. meaning your carb was flooding badly.. but now you have a new carb and should be past that.



secondly.. crap in hydraulics. means that you need to pull the pump off, and the rear cyl off and clean everything.. as the gunk is everywhere in the system and lines... don't worry about bottom of sump, just the lines, pump and hyd valves under the cover.
Even your safety valve could be stuck open, your unload valve fouled up, etc, etc, etc...

How does tractor run with pump off?

The "cracks" are separations between intake and exhaust manifolds. in other words they are not cracks but are supposed to be there.

(quoted from post at 14:27:55 10/31/13)
How does tractor run with pump off?

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Exactly the same. So last weekend I ran it with the new carb, the new sediment bowl (had to replace the old one because it didn't have enough clearance from the new carb), and the hydraulic pump off. It ran like a dream for about a half-hour, then turned in to the same old nightmare.

I noticed looking into the sediment bowl again that the bubble at the top was back. I said before that I tested the fuel line and it ran with plenty of volume, but I didn't let it run for very long. I'm thinking this weekend I'll put a jerry can under it and let it drain for a few minutes. It's possible there's enough gunk on the intake screen in the tank that gas flows for a while and then it clogs again and won't flow. Someone suggested something like that.

Either way, I have a replacement tank for the old rusted one. It has POR tank liner drying in it right now. I still need to paint the outside, then I can swap tanks this weekend.

I just don't know if the vacuum problem happens first or the fuel problem. I tried spraying everything with starting fluid again (probably the fourth time, I just can't convince myself that there's not a vacuum leak somewhere), but nothing.

{edit - I should add that I had to drill out the banjo bolt a bit more to line up with the new sediment bowl.}

So what happened with the hydraulic pump? I'm a noob. When I rebuilt the pump the first time, in the spring, I couldn't figure out what the valve seats were for and what to do with them. So I left them out. That was a *good* thing. When I rebuilt it in the fall, after the bolts came loose and all heck did too, I found a good diagram of where they went, and put them in.

[b:dc148c3295]Right on top of the old ones, which I didn't think were actually there.[/b:dc148c3295] You can see where this is going.

So, luckily I didn't try to run it long that way, but still, I got a few things destroyed again in the pump. The problem now is that three of the seats-on-a-seat came back out pretty easily, but the other three are being difficult. Two of them I can wiggle with a punch, but they won't come out when I try drill bits and extractors. (Got a new extractor set last night that might help.) But the last one is partially destroyed - lots of cracks so it's pressed against the walls of the shaft now and won't budge.

Which means I need to come up with a tool to pull it out. Snap-on makes a blind bearing puller that might work, but I [i:dc148c3295]think[/i:dc148c3295] I can make something like the original tool. I have a 4" long, fully threaded 1/4" grade 8 bolt. I'm going to file off the edges of a 1/4" nut until it fits in the shaft under the seat, maneuver it inside the pump until it's under the seat, thread it onto the bolt (with a 1/4" grade 8 nut and some washers way up on the bolt already) about a half-inch, pull it up under the seat, then tighten the nut on top without letting the bolt turn. That should draw up the seat, which is just held in by friction. I'm counting on the valve seat moving before my nut threads strip.

Any votes on whether that's a reasonable idea? Is pulling this out something I should be able to find a shop to do? It's an awfully small seat...

OK - finally got this figured out. Had to put it into the shop to get it. It [b:51e66a502c]was[/b:51e66a502c] the distributor. Specifically, it was the advance. I knew the advance weights moved pretty freely, but the springs worked like they were supposed to, so I assumed it was supposed to be kind of loose. Nope. The advance weights were opening up a lot with the slightest twist. They opened more with more twist, which is right, but there's apparently not supposed to be [i:51e66a502c]that[/i:51e66a502c] much play in them.

So, by the time I got it into the shop it had a more serious problem, it had developed a small head gasket leak, which they fixed too. It didn't have that problem last fall - the compression was good on all cylinders. But it's been running pretty hot when I could get it to run at all, so I'm not surprised.

But I was right to keep thinking it was timing. I had set the timing, but with the advance weights slopping around in there, it was impossible to properly set the timing. I guess there's some kind of snap-ring or something that's supposed to hold the timing weights down, and that was gone, or loose or something. They say it's working great now, so I just need to pay for the return towing and get back to work with it.

Thanks to everyone for the help and suggestions!