311b warming up issues

mcogar88

New User
Hi, everyone I'm a farmer from Wisconsin and I run a horse boarding facility. I've been having a issue for some trouble with my 311b. It's like clock work once it warms up the tractor cuts out and only wants to run on choke. I went threw the zenith carb with a fine tooth comb, a half dozen times or so and it never made a differnce. So I changed the fuel filter, tried running with the gas cap off, changed the old fuel line, to a hard line just in case I was getting crimping, got rid of the inline filter that had been installed and am now just using a sediment bowl which I've never had anything collect in. And finally I broke down and ordered a reman marvel carb and it still acts up. I'm thinking of pulling the tank off because this screams a fuel issue to me but I am honestly lost. Tried replacing the coil as well no luck thinking it may be a ignition issue, and pulled all the plugs and they look great. Oh and I sprayed starting fluid around the intake and it made a very very small increase in rpms but nothing I can imagine that would make a difference. I do know the head gasket is going out and I'm thinking that may have something to do with it. Any suggestions would be appreciated, I'm by no means a master mechanic and this thing is twice my age so I've never really been around older case tractors much. I really appreciate everyone's time. Mike
 
An electrical issue will mimic fuel problems every time. Weak magnetos on the older tractors will drive a guy nuts until he takes it
apart and recharges the field magnets. With your distributor, I'd say you've a condenser problem, perhaps a coil. The insulation breaks
down internally and they produce a weak or intermittent spark.
 
Your problem is more than likely ignition problem rather than carb. We had a 430 that when we drove it up the road, it would start sputtering about 4 power poles up the road. took the carb off several times, with no positive results. Changed out the condenser, in the dist. and it has run with no issues since.
Loren
 
(quoted from post at 15:46:02 06/12/15) Thanks guys, I tried the coil with no success, I will defently try the condenser.

If it keeps running on choke or you can keep it running by messing with the choke when it gets warm, keep looking for some place where additional air is getting in as heat expands something. Electrical issues will mimic fuel but often the tractor choke will not be enough to keep it running. They all are a bit different.

You said you noticed a difference (small) when spraying the manifold so I would not discount a potential leak. Sure sounds like a warm up is opening something up to more air if you can keep it running. Why did you mention the head gasket?

Good luck and please let us know what works. Remember it is basically fuel, air and spark....hard sometimes when you are trying a lot of small steps to tackle a frustrating running issue.
 
Well replaced the the condenser, rotor,
and points if that's the proper name.
The point were wore out but it didn't
help my issue at all. I did l however
try starting fluid around the intake
manifold and found out I'm able to stall
the tractor out if I spray enough. It's
right where the intake manifold and
exhaust manifold meet. I'm going to try
and get them of monday. Looks like there
may have been a gasket there at one
time.
 
well , there is the problem ,, must be a big hole too , if you can flood out the motor ,, just for fun , if you can see the missing gaskt you could plug it with sumthin and see if that improves the running longer .. I have 3 sc's every durn one ,developed that problem rite after i got them runnin well enuf to go to the field and attempt to earn their keep ,, but no go , once we got to work .. sputter misfire , buck snort , junk , dam!...on all 3, it was same problem , the exhaust manifold had craked and was sharing gasses with intake ,, because of the extreme temp diffes defense it probably preheated the fuel
 
Took of the intake and exhaust manifold today. Where I thought the hole was, and where I could stall it out from spraying starting fluid is sealed. It's flat cast iron, I don't see any crack at all, I don't see any cracks anywhere to be honest. Does anyone think it's still worth replacing, maybe there's a micro crack I'm not seeing.
 
This is where the intake and exhaust manifold are bolted together for refrence. So I guess it would be the very bottom of the exhaust and very top of the intake
 
Any chance a intake or exhaust gasket could be causing this? Some the the exhaust look like they could be leaking but the intake look good. Just trying to figure out if I should spend the money
 
(quoted from post at 15:36:54 06/15/15) Any chance a intake or exhaust gasket could be causing this? Some the the exhaust look like they could be leaking but the intake look good. Just trying to figure out if I should spend the money

I really don't think the manifold is the problem. I find it hard to believe you can flood an engine out with stating fluid. Ether is an accelerant. If anything it would have made the engine increase in rpms, not stall.

Are you sure you have a constant fuel flow? Have you removed the plug on the bottom of the carburetor after the engine stalls to make sure the gas is still flowing?
 
No I have not, at the very minimum I need to replace the intake and exhaust gaskets. They where ruined when I took the manifolds of. I have drained the entire tank of gas and it seems to flow great out of it.
 
(quoted from post at 08:37:27 06/15/15) No I have not, at the very minimum I need to replace the intake and exhaust gaskets. They where ruined when I took the manifolds of. I have drained the entire tank of gas and it seems to flow great out of it.

You described the problem as keeping it running with choke... When it gets warm and acts up and you choke it, does it continue to run or does it eventually die no matter what you do to the choke/throttle? If you are keeping the engine running warm by applying the choke and it seems to run without sputtering out then that lends itself to air/fuel possibly.

If applying the choke only prolongs the running a short time when it begins to sputter and it ALWAYS dies even with the choke on, then how long does it take before it will restart? Do you have to let it sit? Do you have to choke it?

You can narrow the fuel/air versus electrical through elimination of some of these. If it dies out no matter what you do, we would want to know what happens to restart it. If you are able to keep it running with choke for an extended time I would be more inclined to keep after a fuel air issue.

What is the deal with the head gasket? Did it overheat real bad once? Head get warped?

Depending on how and where you actually sprayed and when it was warming up or already warm also makes a small difference. Modern starting fluid is not ether anymore... more alcohol but still should be go fast stuff and not take all the air out of the mix. Keep after it. Is the carb gasket to manifold good and snug with no leaks. I had a Allis Chalmers that had a manifold bolt work loose and gave me fits until I found it.

You should FOR SURE replace the manifold gasket and make sure you torque it back on to specs. do not go crazy and crack the cast iron but make certain you seat the new gasket. Cast iron changes when it gets warm and cools and if you really stalled the engine by spraying into some "opening", then the gasket replacements is cheap therapy. Take a close look at the carb to manifold gasket area too.
 
I replaced the manifold gasket and I
cant seem to get it to stall or Rev up
anylonger. But I also ran out of
starting fluid so I didn't get to
experiment for long. Unfortunately it
didn't make a differnce, I also drained
10 gallons of fuel from it and the flow
was always strong and never had any
issues. I will say it did run longer
before my issue started but it's also
colder out so that may play some
differnce. This only happens when it
warms and I have to play around with the
choke to keep it running, in and out I
guess I should say. It's not just pull
the choke and it runs if that makes
sense. If for some reason it does stall
it starts right back up. I try to do
everything with the tractor warm sense
that's when it acts up.
 

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