fuller and johnson won't run-help


New member
I have a 1929 fuller johnson NC rebuilt, new rings new mag. 2 years ago it started easy, 1st or 2nd pull, It sat for 2 years and just recently wanted to start it again. It will not start. Fresh gas and good spark.what could have went wrong with it sitting for 2 years?

Mike Hole

Are you getting fuel to the mixer ? The check valve in the tank may be stuck.
Also make sure the intake valve is free.



New member
yes, its getting gas.if I keep turning it over it will come out the back of the cylinder.I also have 2 new spark plugs.I also have an inline spark checker and it fires every time.obviously I cant see inside the combustion chamber but it seems it's just not igniting the mixture.


New member
nothing has changed since it was last run,timing marks line up and the plug sparks when the mark on the flywheel line up with the pushrod.It makes no sense to me that it won't run.It doesn't even seem to want to try to run.I would say for every 100 times I pull it over 20 times it will fire off very weak.

Andrew Mackey

By any chance, has the plug got wet with gas? gas will short the pug under compression. You will have spark out of the engine but under compression, the spark will short across the insulater. try heating the plug with a propane torch to dry it out. if you have gas flowing out of the cylinder, the engine is definately flooded. You need to remove the plug and dry the cylinder out

Tom G

Have you considered that your spark is weak? You might try cleaning the magneto points. Maybe even replacing the condenser. Having a spark doesn't mean that it is strong enough to fire the plug under compression.

Also, how is your compression? Did the rings stick while the engine sat idle? Is a valve not seating?

Fuel, fire, and compression. Sounds like you have fuel.


New member
the spark will jump a 3/8" gap.the spark is purplish.I bought the mag new so points and condenser are new.compression is good and rings are not stuck, I had them out last week.I don't understand why the plug won't fire under compression,cars have much higher compression and they fire fine, even older cars with point type ignition.

Rich Mueller Sr

Andrew is right on the mark on plugs, out of curiosity what kind of plug wire?? IT IS copper core right?? Not carbon core?? to much resistance on carbon core will mess up coils etc. Take the cover off mag and run a white business card in between the points while closed, this should come out clean, no oil on them, also I have a '29 NC spoker heavy flywheel, it can be cantankerous at times, real touchy on fuel. One way to clear the cyl of gas, and will bump start them to, is set the retard lever to start, UP, and fling the flywheel towards the head instead of the way you start it, it will either fire, or maybe fire when the exhaust is opened and clears gas out. I have good luck on bump starting it like this after a good choke or cranking it and flood it. Does yours have the gas tank in the base? Another issue is if the tank is in the little base, when you drain the water out, IT WILL drip in the fuel pipe inlet on tank, unless it is sealed real good, been there done that and no drain in bottom of the new tank, Berrymans fuel injector treatment is your friend, and friendly to igniter engines to, some of that additive will not fire good with igniter engines ...Goodluck..

Tom G

Nice looking engine. First thing that I would do is to get a NEW spark plug. The others are possibly wet fouled. Try cranking the engine with the needle valve barely open and gradually open it. Sounds like you flooded the engine and fouled the plugs.

Kirk Taylor

New member
what is the cheapest easiest way to try something different for ignition?
I've been following your responses and can make a few observations.
First, if your mag will jump a 3/8" gap and gives a consistent spark when hooked to the plug through an in-line spark gap, there is no apparent need to change ignition systems; that's as good as it's going to get.
Second, if I understand correctly, you stated that the engine received new rings two years ago and ran perfectly after that. Then, you stated that you removed the rings recently and that you have great compression. I have to ask why you removed the rings recently. Was the engine leaking compression out the back? Did the engine leak compression out the back after you put the rings back in?
Third, you state that the engine has great compression but you get gasoline running out the back of the cylinder. You also say that every once in a while the engine will fire but very weakly. When it fires, does it blow out the back of the cylinder? If you roll the engine backwards against compression and hold it there for say five seconds and release the flywheels, is there enough compression remaining in the cylinder to spin the flywheels forward or has it all leaked off?
If I were to drive to your place, after verifying that everything is mechanically and electrically sound, I would do the following:
1) Drain the tank and refill with known good gasoline or at least confirm that the substance currently in the tank is in fact nothing but good gasoline. I've seen people fill up gasoline tanks with kerosene, water, and relatively new gasoline that just wouldn't light and then scratch their heads wondering what's wrong.
2) Remove the spark plug, ground the spark plug wire, fill up the hopper with hot water, squirt six or eight shots of oil from a pump oil can into the cylinder, and spin the engine over several dozen times to dry it out and re-lubricate the cylinder.
3) Put in a clean, dry spark plug gapped at 0.021" - 0.023" without the in-line spark gap.
4) Open the needle valve ~ 3/4 of turn or whatever that particular engine likes.
5) Break the compression and bring the engine up on top dead center.
6) Sock my hand over the air inlet and quickly roll the engine to pull in fuel and also quickly remove my hand from the mixer while it's still sucking.
7) Continue to roll the engine through the exhaust stroke, the intake stroke and up to compression.
8) Hold the intake valve open and turn the flywheels until the crankshaft is pointing straight down. This will break part of the compression.
9) Stand behind it and give the flywheels a sturdy flip. If it pulled fuel up, it should light.
It may need choked one more time; all engines are different. Use your hand instead of merely closing the choke and spinning it over. Some engines flood very easily and will go from dry to severely flooded in one turn.
I am guessing that, for whatever reason, the engine got drowned right out of the gate. That washed the oil out of the cylinder and dropped the compression. Modern pump gasoline sometimes doesn't light well anyway, especially on a cool, damp day. It most certainly doesn't evaporate very well making it difficult to dry out an engine. The combination of a wet engine and reduced compression killed it.