Fuel Delivery Problem...?

Deino · Post by **Deino** » Sat Mar 07, 2009 2:51 pm

I took the M38 into town today, about 15 miles or so, and after I stopped and let it sit for a while, upon restart it seemed to be starving for fuel. On the way into town it ran fine, though. The problem got worse and worse to a point where it idled very rough and hesitated in acceleration. It seems to run better with the choke 3/4 of the way out. It has a brand new Solex carburetor. I'm thinking there's trash in the carb since I've been putting gasoline from gas cans that have been sitting for a while into the tank. I replaced the in-line fuel filter that had been installed by the prior owner, but the problem still exists, if worse than before.

I believe it's a carburetor problem, but I suppose it could be a weak fuel pump, too. I had some problems with hot starts when I first installed the Solex, but that problem was resolved when I installed the fiber spacer between the carb and manifold (d'oh! for not putting it on in the first place).

Any ideas?

OKCM38CDN · Post by **OKCM38CDN** » Sat Mar 07, 2009 4:15 pm

Check th fuel tank vent, it may be clogged and no air getting into the tank, causing a vaccume... one way to check is if it starts doing it again, pull over and take the fuel cap off... if it starts to run better then there is your problem...

Hope this helps...

DJ · Post by DJ » Sat Mar 07, 2009 4:22 pm

Could be bad gas too, try filling up with some fresh gas.

Deino · Post by **Deino** » Sat Mar 07, 2009 6:07 pm

I checked the vent and it's not the problem. Thanks for the suggestion though.

So far as bad fuel goes, it's certainly possible, but wouldn't bad fuel cause the problem from start instead of waiting for 30 minutes into a drive? I only ask this because I ran it some the day before with no problems. Perhaps trash finally made its way into the carb after prolonged running.

I'm going to check and see if it's still doing it tomorrow. If it is, then maybe that's the problem (the bad fuel and possible trash). But if it runs fine for a while, I dunno what it is.

Any more input would be appreciated.

Post by **Ryan_Miller** » Sat Mar 07, 2009 9:20 pm

After having some fuel problems, I tested my fuel pump (fine) and then took my carb apart to find a lot of trash from a fuel line that had some rust in it.

My jeep would accelerate OK, but not idle or hold a steady throttle.

Taking the carb off and apart is fairly easy. I was hesitant at first, but Wes talked me into it and it was not that difficult to dissasemble, clean and reassemble after all.

Just a thought.

Post by **wesk** » Sun Mar 08, 2009 12:14 am

Is your area warm? Could be vapor locking. The gas line from the pump to the carb needs to be at least 3 or 4" away from the exhaust manifold.

Deino · Post by **Deino** » Sun Mar 08, 2009 8:26 am

The fuel line is a good distance from the exhaust manifold. Plus, my dad and I were checking it out yesterday with the hood up and we had a good breeze going from the front pushing through here...and it still idled rough.

During acceleration, it will have trouble at lower rpms and sputter and act like it's about to die. Even at higher rpms at full acceleration it sometimes misses, but it stays alive. The choke is pulled out to 3/4 at this point to keep it going.

I'm going to take the carb off today and go through it, but first I'll start it up and make sure it's still having issues. I want to rule out some things.

Does anyone have a link to a good diagram of the Solex carbs for the little 134's? I'm on really slow dial-up and it would take me forever to find a pic.

Post by **wesk** » Sun Mar 08, 2009 9:10 am

Although the 68 to 72 VW's used the 28, 30 and 34 solex series the 17 page training guide at my photo site can still be used for your 32 Solex.
http://jeepfuelsystem.mypicgallery.com/