Ford GPW motor stall when warm

[johnchap8]

Looking for some direction and words of encouragement. 1944 Ford GPW that my grandpa restored. It has been sitting for 5 years but was fully operational when parked when his health went down hill. I have drained the fuel tank, replaced fuel filter, new carburetor, new spark plugs, new ignition coil, and new condenser. Motor is a little tough to crank but will crank while holding my hand over top of carb. runs consistent with great throttle response until a few minutes after motor is warm and thermostat opens up. motor then starts to bog and stalls out. not much success in cranking after warm, may crank and run for a minute and then bog back down. after letting it cool down for an hour it will crank back up and repeat same symptoms.

I feel like there is something I am overlooking? are these symptoms of points needing to be adjusted? check the timing? Jeep was driven in parades and in great shape mechanically prior to being parked.

[51 CJ3]

By “cranks”, do you mean it starts and/or runs?

edit: I get a little cranky on some of this stuff. I got called out on a service call a short while back. The call was motor wouldn’t crank so I took a fresh battery with me on a 100 yard hike (boat dock). Motor cranked fine but would not start. The guy had run it out of gas.

[johnchap8]

no issues with cranking as it turns over no problem. my reference to cranking is starting AND running.

[bmorgil]

Hello John! Yes clarify "cranks" for us. I think you are saying it runs great when its cold then dies as it warms. By "cranks" I am guessing you mean firing. How are you operating the choke? If you have to put your hand over the carb, I am thinking the choke isn't sufficient to start it? Is the choke fully on when it starts to run poorly?

The start up process that seems to work well on a stone cold engine would be, pull the choke all the way out. Pump the throttle 3 or 4 times. Turn the ignition on and crank the engine. The instant it fires press the choke in to 1/2 way. Keep the engine running with the throttle.

Give us a little more information John, I am sure we can figure it out.

[johnchap8]

thank yall for some response. that is the start up process i follow. I know that the stone cold engine can be tricky to get going. I feel like I have found the sweet spot for the choke during the warm up as any adjustment will choke it off. once warm and the motor starts to bog, the motor will not respond to any throttle, it just bogs out. i can see the fuel being squirted into the carb from the accelerator pump, so i know that is functioning properly.

[bmorgil]

OK I got ya now. First guess, it sounds like it might be getting too much fuel. The cold engine may run with it but the warm engine wont. If you are seeing fuel squirt from the accel pump, it is not running out of fuel. I take it it isn't responding to the fuel shot from the accel pump. Is it acting rich as it bogs out, smoke rich smell? If it is, the float might be sticking open, flooding it out when its warm. It would struggle to start after that till it cooled off and evaporated off some of the fuel.

There's my swing at the first pitch! Keep us posted John, it cant be much on these motors. Shoot some photo's of the project.

[51 CJ3]

To go with the above idea I’ll throw in a possible air leak. Possibly a crack in the intake that allows more air in when it warms up.

Another boat “crank” story: the same guy a couple weeks later calls me and says “boat cranks but won’t run”. This time I ask more questions. After asking the same question 5 different ways I finally get something like “it starts but won’t move”. Thinking at best I have to change a stripped out prop hub and the worse case would be changing a lower unit I was surprised to learn the boat not only started and ran fine, it also shifted forward and reverse fine. Someone had done a panic stop from forward to reverse hard enough to pop the throttle linkage loose. The motor simply wasn’t receiving the message to turn faster than idle.

[johnchap8]

bmorgil,
these are the same symptoms as before I changed the carb. I can make sense of the stuck float on the carb that had been sitting for 5+ years, but what do you think likelihood of stuck float on the new carb is? when it starts to bog, it definitely starts to smell rich.

51CJ3,
I will look for some cracks around the intake.

these motors are super simple which is why i think i am missing some minor adjustment that will get it back going.

I tried to attach a picture below of the jeep, hopefully it worked.

[51 CJ3]

Nice looking jeep. The picture even posted right side up which better than most of my attempts!

[johnchap8]

thank you. gonna get it back going and then add a top and mount the shovel and axe. hopefully all by summers end. I will do some more inspecting and tinkering with the choke over the next couple of nights as I have time to work on it and then report back.

[bmorgil]

Nice looking Jeep!

I am wondering if it didn't pick up some crud in the carb. It could have junk floating around in the fuel bowl.

[51 CJ3]

That’s a good possibility too. Especially if it was parked with E-10 in the gas tank.

[johnchap8]

My grandpa religiously only ran 100% gas in it. And I did drain the tank just to be safe before I started tinkering with it again. And filled back up with 100% gas. I hope to report back soon with new information.

[bmorgil]

I am just guessing that's even it, but it could be. Any fuel sitting in the carb for 5 years will usually evaporate out. The volatile ingredients go first, and the detergents and additives usually dry up into something not nice. If that occurred, it could be gumming up the float and/or needle valve.

[johnchap8]

I was able to adjust the choke and keep it running after it warmed up..making some progress!! However it did seem to sputter and die off after a couple more minutes - warm motor and choke off. Did continue to smell very rich. It will start back up and repeat sputtering off after another minute.

Should I try to keep making adjustment to the carb? I thought about putting an inline 12v fuel pump to keep 2.5-3 psi to ensure fuel is pressurized and making it to the carb correctly to rule if fuel pump might be a culprit.

It’s just odd that it runs great during warm up (half choke). Seems if it was fuel related and not getting enough gas to carb that this period of run time would also be an issue.

[gmwillys]

A quick and easy check/ or farmer fix that I would attempt first would be to pull the air horn off of the carburetor, then at a high idle cup your hand over the throat of the carb to cut off the air flow until it almost dies. If you have crud in the idle circuit, it tends to get sucked out with the vacuum spike with no air flow. It may take a couple of tries, plus I use a dose of either Seafoam or Berryman's B12 fuel additive in the fuel tank to loosen the crud. Fuel pumps typically work or they don't, but a tattle tell sign to see if your fuel pump is leaking internally is to pull the dip stick to see if the oil is being diluted by fuel by way of the diaphragm leaking into the crankcase. There is a weep hole that the fuel should leak out to the outside, but not always.

[bmorgil]

I agree with gm, it looks like there is crud in the carb. If the trick gm proposes doesn't get it done, it sounds like a carb tear down is in order.

When it is sputtering when "Warm" and the choke "Completely Off", what is the engine water temperature reading on the gauge? Are you saying it wont idle when it is warm it just dies? Or, you cant keep it running after it warms? If you hold the throttle up a little will it keep running?

[56willys]

Just thinking of ideas; could the float be out of adjustment enough to make it not run?

Another thing, what carb do you have? If it is a Solex, I have heard of people having trouble getting it started when its warm. Because it has too much fuel, since it boils out of the bowl when warm.

[johnchap8]

It is a new Solex carb that i replaced the older solex with. could possibly be that the float is that out of adjustment on the new carb that i put on.

it idled after warmed up yesterday after i was able to adjust the choke so the choke would be completely off. water temperature stays around 180 when warm. i just cant seem to keep it idling very long after the choke is off and the motor is warm. throttle response seemed to not make a difference, when it wanted to bog there was no saving it - which is why i am back thinking its a fuel issue.

[51 CJ3]

I have read talk of the new solex carbs being picky about how much fuel pressure they need. Some people have had to run a fuel pressure regulator between the fuel pump and the carb. I will see if I can find it but it seems like it was 2 psi or less.

[bmorgil]

I definitely think there is something up with the carb. If it will run with some choke when warm, the problem is most likely in the idle circuit of the carburetor. If it runs with some choke the problem is not fuel pressure, it is not getting enough fuel through the idle circuit. Using the choke pulls fuel through the main circuit, allowing the engine to keep running if the idle circuit is plugged. If there is too much fuel pressure you wouldn't need any choke at all and the motor would flood without any choke.

[gmwillys]

This is a common issue with the Solex carburetors. If you get them tuned for off idle cruising, they often stumble at idle, and vice versa. Most of the time, the Solex is set off to the side and a replacement Carter carburetor is put into its place. The Solex is incredibly sensitive to tuning for perfect operation.

[LarrBeard]

In moments of frustration with Solex carburetors, one person made the following suggestion:

A. Remove the carburetor.

B. Have a friend come over to your shop at night.

C. Ask the friend throw the Solex as far as he can in some direction - preferably into woods or towards a lake or pond..

D. Never ask him what direction he threw it!

See, we have all kind of good suggestions.....

[bmorgil]

Not a lot of love for the Solex. The French stopped making it in the late 80's. After that they were made in China or Hungary. They are known to work good or, real bad.

[johnchap8]

i think i will plan to go through and clean the old solex carb that i took off since I knew that it was operational and functioning well enough to drive for several years prior to sitting up. it does sound like the solex carbs are hit or miss from some of yalls feedback.

[51 CJ3]

My 3A has an older Solex. It didn’t give me any trouble after I went through it. I found the base gasket to be a bit of a pain because there isn’t much for it to sit on and can be bumped out of position pretty easy when reinstalling the carb.

[LarrBeard]

When I was playing around with the Carter on the '48, I went exploring to verify jet and orifice sizes.

I found that a set of micro drill bits did a good job in verifying jet sizes and - as a bonus - they were handy to clean out all of the 35+ years crud that managed to cling to passage walls.

A typical set:

https://www.impressart.com/540-20-pc-micro-drill-bit-set.html

These are standard English sizes - like Old Jeeps, not Chinese metric.

[gmwillys]

There is only a couple of conceivable absolutes when it comes to a Willys restoration. (1) The replacement body kits need a lot of work to make them fit correctly. (2) Solex carburetors rely on the moon and the stars to align perfectly to work throughout the throttle ranges. The cavoite to this rule, is never say never when it comes to a Willys.

[bmorgil]

The good news is the original Carter is still available. If you cant get the Solex to work, you can always go with the original carb. Here is a link that might help with the Solex.


https://willysjeepforum.kaiserwillys.com/showthread.php?938-Solex-Carburetor-Tips-and-Info