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Starvin' for gas ?

Boys and girls, I am losing my mind over this problem and I hope that the collected wisdom here will help save what shred of sanity I have left. In a nutshell, when the engine is cold it runs fine, when it is warm it idles fine, when I take it on the street it bucks and stalls after about 5 minutes. Acts like it is starved for gas.

Here's the 411...

1971 Type 2 Dual Port 1600 ?B' Series engine (I know this is a '70 engine but it has been running great ever since it was rebuilt by PO about 5 years ago) Bocar 34-PICT-3 carb 009 Distributor

And now the story...about 3 weeks ago I was coming home from the lumber store when Ol' Phred starts bucking and stalling. I limp home and park. I unload and try to start the engine and VROOM, no problem. Since I have other things to do, I shrug my shoulders and forget about it. Next day as I am driving home from work, same thing...bucking and stalling. Again, I manage to limp home and park it. I do a thorough tune up (valves, points, timing, etc.) with no change. Next thought is the carb, take it out and do a complete cleaning and rebuild. Lots of rust and junk in the bowl. Carb looks like it hasn't been cleaned in years (well, at least not in the 3 years I've owned it). Did find that the plunger on the idle cutoff solenoid had broken off and gotten lodged in there. Replaced the solenoid. Put the carb back on and the problem is still there. Since that time I have changed the in-line fuel filter, the gas tank filter, and the intake manifold gaskets. I am running out of ideas and sanity. When the engine is cold it idles just fine and when its sitting in the driveway warmed up it idles as well but when I get it on the road for more than 5 minutes then it starts up all over again. Its acting like its starved for gas or getting WAY too much air from somewhere other than the carb. The automatic choke has been disconnected ever since I bought the bus (in Texas its no big deal) so I know that isn't the cause of my worries. What could I be missing? Is there a jet in the carb that might still be clogged that would cause this type of problem? Any and all suggestions gratefully accepted though with my lack of available funds it might take awhile to implement.

Thanks all

Jeffrey

Reply to
J Blair
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Try a run with the fuel filler cap loosened (don't do this when tank is full and omit the sharp turns). If no bucking/stalling, the tank is not venting properly.

Check the actual fuel flow out of the tank. Maybe you already did this when you replaced filter? Let the fuel flow into a gas can for a minute or so. (Do this *outside*, not in the garage!)

That's not an absolute test though; I've seen cases where the gunk inside the tank sloshed around whilst driving, clogging the mesh screen intermittently. If you suspect that, pull the fitting off the tank outlet and flush the tank out (best done when near empty...)

You could still have an ignition-related problem. Sometimes, engine bay temp will affect things like the condensor or the coil, causing weak or intermittent spark. If you run out of ideas, I vote for wholesale ignition parts replacement.

One last test: Get a long wire and run it from the Hot terminal on the Coil all the way up to the cab. Put a voltmeter on the seat so you can watch it as you're driving. See if the coil voltage stays at ~ 12V when the bucking begins.

Speedy Jim

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Reply to
Speedy Jim

I have a '73 Thing with a 1600cc dual port, had exactly the same problem. Acted like it was vaporlocked, but idled fine even when hot. After rebuilding the engine and tranny, and replacing the ignition components it still did this. The fix turned out to be a wholesale replacement of the fuel system. The tank had corrosion. Replaced the tank (with screen), pump, and lines. It didn't work until I blew compressed air in reverse through the steel part of the fuel lines ( the line through the tunnel while the tank was disconnected.) The main thing was getting all the gunk out. It took a few tries as it was hiding everywhere. Hope my experience gives you some ideas for where to look next.

Reply to
Ed Botwinik

I second all above, another thing not to completely rule out are valve/s, could you have burned a seat(s) having it ackting up when warm?? Far fetched but....

J.

Reply to
P.J.Berg

SNIPPITY-SNIP

Looks like the fuel pump was the culprit after all. The old one was a Mexican knock-off that was sealed so I couldn't get into it to look at the screen or the diaphram. Scraped up the last of my pennies and bought a new one that I can disassemble if necessary. Installed it yesterday and was able to get Ol' Phred back home but still needs major carb adjustment (after trying to adjust the carb to a failing pump its really out of whack). One thing I found out was that the pump was doing OK at idle but when there was a load then the pump was not able to keep up with demand, the more demand I placed on the pump, the faster it failed. Thank for all the suggestions, now I have lots of other things to check as well, just to be on the safe side. You guys are the best.

Thanks

Jeffrey

Reply to
J Blair

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