Fhead wont stay running

Well yesterday was my first time firing up the 3b since sometime in december. After cleaning out the old gas, getting fresh gas thru the system, and cleaning up the spark plugs, the jeep fired up with the choke on. I am running a Solex by the way. It ran smooth as usual, for about a minute and half or so, then it just kinof died out. started it back up again, and was able to keep it running for a minute or so, on half choke, then it coughed and died again. Pump the gas a couple times it fires back up again but wont stay running for more than 30
sec or so. Once it warmed up, i was trying with the choke all the way off, and just couldnt keep it running for more than 20 seconds at a time. Every time id wait 15 sec or so, pump the throttle, and it would do the same thing.Run 20 sec then just die. Really stumped here guys please help! Thanks
Ben

Final note: while it is running it "hesitates" (darn near dies) any time i open the throttle

 

Check the fuel filter and lines for being plugged and check for vacuum leaks. Nickmil

 

thanks for the reply. I have a fresh gasket under the carb and due to the pcv system not being complete, i just have a bolt screwed into the intake manifold so vacuum shouldnt be a problem. i presently dont have a fuel filter installed so that cant really be the problem. Any other ideas? I tried again today with the same results. : (
ben

 

Check the carb inlet, sometimes they have a screen filter. Without a filter, you could have some nasties in the carb itself, especially, if you had to "clean out the old gas". Tanks get all sorts of stuff in them, I'd get some kind of filter on it.

 

Once you have confirmed its not a fuel delivery problem check the points and condenser, I had a very similar problem with my F4-134 this spring. It turned out to be a weak condenser. The Jeep would start but barely run, after checking almost everything else I changed the condenser and runs like a champ.

 

the twenty second thing sounds kinda like a varnish problem.

My Fhead was acting weird, also. Set the points to the Nth degree, and it would run fine for about a day and a half. Then it wouldn't. Had it setting in the garage with the tailpipe on the outside, and let it idle. Idled rough until the thermostat opened up and the would run like a champ - until the thermostat closed, then it ran ragged. I got real tired of resetting the points every two days so I ordered up the Pertronix (#1548) for my distributer (IAY 4401B) and the problem went bye-bye!. R)

Go Pertronix!

 

On my A1 similar behavior was due to a plugged tank vent. Cracked the fuel tank cap and it ran fine.

 

Thanks for all the replys guys! My jeep is still only basically only only a rolling, running chassis, so at this point my "gas tank" is a coffee can, so i know the gas is clean...and fuel delivery is good...i accidentally cranked it without the fuel line hooked to the carb haha. for all the more points and condenser cost i might just throw new ones in to be sure. Where can i buy good ignition components? i bought points, condenser, cap, wires, and rotor from omix ada so i know theyre not the best quality...can advanced/autozone/pepboys etc look up part numbers for a 62 willys? it still seems to act like its a fuel problem to me but hey if i knew what i was doing i wouldnt have to ask. thanks fellas any other ideas welcome
ben

 

I would have to look to fuel delivery to the combustion chamber, ie, possible prob with flow thru the carb ... cracking the throttle, then it dies, is the key thing here, to me ... big wind, no juice

 

Homebrew is on the right track, methinks. I'd also start with checking for a screen at the carb inlet, if you haven't already. After that, I'd put a rebuild kit on it. Nasty old dried up fuel is your enemy here, Ill bet.

 

You may have a clogged main jet. Most carbs have an enrichening circuit that draw extra fuel for start when the chocke is closed.
The extra vacuum with the bore closed draws enough fuel through the start circuit to get an engine running then the engine dies once the small reservoir is drained. Wait a little bit and try again and the same thing results. "Varnish" the resultant residue of deposited solids from evaporated gas is the usual culprit.
Pull the carb and clean the passageways and jets.
Ign problems, in my experience, usually on a running unit, take a little time to overheat or burn something and then it gets quiet and stays that way.
Bob

 

Thanks for all the replys guys. Ill go over the carb really good and then if it continues acting up ill try replacing the ignition components.
Ben

 

Don't know why the Petronix number doesn't show up all the way. It is 1548 for the IAY 4401