Nat

Member
Help!!!!!! I have an old cub and have had it for a couple years. When I bought it , it had been sitting and carb was all gummed up. I cleaned it out, rewired it as someone had converted it to 12V and messed up the wiring. Fast foward a couple years. It has always started and ran well, but never had as much power as I thought it should have but not a problem. I haven't touvhed it in a couple months as I had a bunch going on. I went out to start it and it wouldn't start. I would sort of hit but not enough to start. It seemed as if it would hit once every other revolution but no more. I figured the carb was gummed up because it had gas running out of carb, so I took it off and cleaned it. No start, and I ran the battery down trying. I recharged the battery and took the dist cap off to check the points ect. Anyway I have now removed the dist to check and reset the points, I turned the engine till number one was at TDC on Compression stroke, have the roter button pointed to number one plug wire and verified by the timing mark on the front pulley and put it back together 3 times now and I still can't get it to start. What am I missing, am I stupid or what. I need some help. BTW, I also have put a new coil on it as the other one was getting hot to the touch so I thought that may have been the problem. I have taken the plugs out one at a time and turned the engine to prove to myself that there was a spark at each plug and there was. I sprayed starting fluid into the carb and still no start. I've gotta be missing something but what. I have the + side of coil to swirch and the - side to the distributer as I always thought it was supposed to be on a negitive ground engine
 
Did you have your finger in the hole when you turned engine over to make sure you were on compression as you could be off 180
 
(quoted from post at 02:13:27 10/27/16) yes I did but just to compare I also turned it 180 to see and still no start

do a compression test and post results.

Also, did you file the points til you had spark?

Check fuel flow.
 
The spark needs to be a blue/white in color and jump a 1/4 inch gap or more for an engine to run well if at all.

Next do you have the firing order correct?? 1,3,4,2
 
I haven't done a compression check but it had started and ran fine for better than a year so I wouldn't have thought that low compression would be the problem but after trying to get it started for a few days I'm ready to try anything. Yes I cleaned and filed and reset the points @ .20 per the tune up specs and each plug has a spark when removed and placed on a good ground and I'm confident that the points are right, cause like I said I took the distrubitor completely out and did them on the bench cause , lets face it they are hard to see in place. I know I put it back correctly and am sure the timing is correct and am positive I'm gettimg a spark at each plug because I thought maybe the distributor cap or rotor buttom may have been the culprit. I took the fuel tank completely off and have a small fuel tank funning to it and I know I'm getting fuel and also know it won't even start if I spray starter fluid into the carb throat. I've got to be missing something but I can't figure out what it is
 
the firing order shouldn't have changed while sitting there and it ran fine before, I don't meen that to be smart but the problem has started whil it was sitting in the shed. Not that someone couldn't have ghanged the plug wires but they don't appear to be out of place and as they are pretty close if one had been changed it would be obvious I think.Am I correct in saying that the + side of the coil goes to the switch and the - side to the distributer? That is the way I seem to remember doing it in the past but like your handle I'm getting up there and memory isn't what it used to be
 
What ever your ground on the battery is it the same that goes to the distributor. So if it is - ground then the - side of the coil goes to the distributor. Most of the time when an engine has sat for a while and not been run the points need to be cleaned. I buy a lot of non-running tractors and most I drive off the trailer running simply by cleaning the points. I winch them on but drive them off
 
Heat the plugs on a brick with a propane torch. Heat them until the ground electrode is almost glowing. This burns off deposits and carbon. Put a teaspoon of gasoline in each spark plug hole. put those warm plugs in and it will go. 1342 clockwise from #1 one is at the front! Jim
 
place your hand over the muffler outlet, while someone cranks the engine. is there movement of air?
remove the air pipe that is connected to the carb. have someone crank the engine, is there suction?
 
Reading what you have done so far, I absolutely agree that you should do a compression test. After sitting, valves can get "sticky" and may not be seating all the way. Especially, in an L-head where the valves are in the block. Another thing that can happen is that valve seats and faces can rust up if they are open. That can drop the compression way down until the rust is "run off".

What I would also suggest is to get a friend to come over, and do the pull start effort. Put the tractor in 3rd gear, and pull it around the yard or a field. getting the engine turning over at operating speed will help immensely to get it started. when and if it does start, let it run and completely warm up. Remember, when you are cranking a battery ignition setup, the voltage drop due to the starter running will cause the ignition coil to drop it's output correspondingly. If you pull start it, that doesn't occur.

There are some other good suggestions that have been made, but that is where I would start. Check compression, and try the pull start method.......just remember to do it in 3rd gear, and don't pull it too fast. 2-3 MPH is plenty.
 
(quoted from post at 06:57:47 10/27/16) Reading what you have done so far, I absolutely agree that you should do a compression test. After sitting, valves can get "sticky" and may not be seating all the way. Especially, in an L-head where the valves are in the block. Another thing that can happen is that valve seats and faces can rust up if they are open. That can drop the compression way down until the rust is "run off".

What I would also suggest is to get a friend to come over, and do the pull start effort. Put the tractor in 3rd gear, and pull it around the yard or a field. getting the engine turning over at operating speed will help immensely to get it started. when and if it does start, let it run and completely warm up. Remember, when you are cranking a battery ignition setup, the voltage drop due to the starter running will cause the ignition coil to drop it's output correspondingly. If you pull start it, that doesn't occur.

There are some other good suggestions that have been made, but that is where I would start. Check compression, and try the pull start method.......just remember to do it in 3rd gear, and don't pull it too fast. 2-3 MPH is plenty.


If you must pull start it please hitch the rope/chain at the rear of the tractor and run it forward underneath. The tractor uses its engine as a frame and it will easily bust your block if you don't use care when pulling it.
 
The only thing you can depend on is when you find the problem,you are going to feel real stupid,I always do. You've pretty much covered all the bases,compression,fire,fuel and timing,just check again to be sure timing isn't 180 off. Not many but a few engines I've started after hibernation had worn rings and/or poorly lapped valves that dropped compression too low to fire while cylinder was dry. My remedy is motor oil in all holes then turn engine over with starter until most oil has blown out plug holes. First attempt to start might foul plugs but compression is much higher. Another thing all of us are guilty of is flooding engine in or efforts to make sure it's getting fuel. That's why I like to turn fuel off and hear it hit a few times on strating fluid before I turn gas on or squirt gas in it. Flooding a worn engine can wash oil from cylinders with same effect as dry engine mentioned above.
 
Your problem either has to be timing or fuel. After cranking as much as you have been, if you pull the plugs they should be wet. If they are wet then your problem is with timing. If they are not wet your problem is with fuel.

Since you have sprayed starting fluid and still don't get any action, I would concentrate on timing. You may not be 180 off but you may be off just enough that it's firing way too early or late. Mark the distributor's current position, loosen the clamps, and rotate it slowly back and forth as you crank the engine to see if you can get any action.
 
Well, I know what the problem is, not enough compression to start. I guess it's ring job time
 
Before you do a rebuild try this. Fill the cylinders with ATF and let ti sit a few days. It could have sticking rings which will cause low compression and if it has sat for any length of time rings do stick and it is a $5 gamble which may save you a thousand dollars
 
(quoted from post at 01:17:00 10/28/16) Before you do a rebuild try this. Fill the cylinders with ATF and let ti sit a few days. It could have sticking rings which will cause low compression and if it has sat for any length of time rings do stick and it is a $5 gamble which may save you a thousand dollars

I would also check all valves too and spray them down with the same mixture. Much cheaper to do this treatment over a couple weeks than a full rebuild.
 
Nat, stop for a second and take a deep breath. Please take a moment and re-read what I posted. Also, take note of what Old, RTR, and some others have said.

Either your valves are sticky/sticking, the seats may have a bit of rust on them (valves faces as well), and your rings are probably dryer than a popcorn fart. None of those make for good compression.

Give it a good dose of your favorite mixture of light lube.....it can be marvel mystery oil, seafoam, it can be diesel, it can be ATF, or it can be 10 wt. motor oil. Give the valves and the cylinders a good dose of it. Turn the engine over without the plugs it in, and work that in. make sure there is enough of whatever you choose in the cylinders to run over into the valves when the pistons come up on TDC. After about 5 mins of turning the engine over, let it set for a day, then do it again, ie. turn it over for 5 mins with the plugs out.
Now, making sure that there is not a lot of leftover oil in the cylinders (which can cause you to hydro-lock the engine), put the clean plugs back in and give it a whirl. you might be pleasantly surprised at the result. It will smoke like a bad cigar for 5-10 minutes of running, and probably slobber oil out the exhaust, but that is ok.

If your compression is still lower than whale crap after that, then you can consider rings or a valve job.

Rant over.
 

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