End of my rope, please help, 1900cc engine + Weber stalling

[nate9871]

Hi all,

About a year ago I put a CB performance 1900cc in my 66 split window bus. Dual webers. It was built by a reputable and very experienced shop.

It runs very strong but I have an issue with stalling and I am at the end of my rope. Has done it since day 1.

Sometimes when I pull up to a stoplight (maybe 20% of the time) the engine will idle for 10-20 seconds and then stall with no warning. It then will then refuse to restart, sometimes cranking for up to 5 minutes before coming back to life.

It is stressful as I have stalled out in some very busy intersections and can't move. Only happens in stop and go traffic, on the highway it never has any issues.


What I have tried with no success:

- 2 different distributors (both electronic and mechanical)
- I have balanced both Webers countless times with flow meter
- adjusted fuel mixture screws a million times, I've tried running it rich, i've tried running it lean
- adjusted timing probably 10 times with a digital meter. Again I have tried retarding it, I have tried advancing it
- Idle set high at 1,000 RPM
- checked gas tank and replaced filter- clean



The longer I drive, the worse it seems too get which makes me think it could be heat related? Vapor lock? When cold it always starts immediately, this only happens when driving.

Is this engine just too big for this vehicle? It definitely puts out more heat than the old 1600.

About to sell the vehicle out of frustration, I don't know what to do anymore.

[TheVintageVw]

have you checked your fuel pump?
When it stalls out and you're cranking, is it putting out fuel?

What about your coil? Over heating maybe? have you checked that?

[Brian_e]

I have had this same problem on 2 different engines now. The issue sounds strange, but I have fixed it both times the same way.

Same problem. Runs fine till it gets warmed up, then it runs out of gas, and won’t re-start. Leave it sit for 20min, and it fires back up after a little cranking.

So here is what I found. The black aftermarket fuel pump stand....just like he one on your engine. The guide hole for the pump push rod is too small. As the engine warms up, the hole shrinks and pinches the pump push rod. The rod can no long pump up and down, so the pump quits pumping, and it runs out of gas. Let it sit for 20min....engine cools, push rod starts moving again. It takes a while to get it going again because you need to crank the engine till the float bowl fills up again.

To fix it, pull the pump stand off, and ream the guide hole out larger, or swap it out to one of the OE brown bakelight style original pump stands.

Good luck. Hope this helps.

Brian
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[Eric&Barb]

Does it only die at idle??

Could be a coil or condenser going bad.

Could be the carbs are flooding the engine.
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[Culito]

I'd follow the advice above ^^
Definitely check fuel flow when it's stalling out. You could try running a cheapie low-pressure electric pump in the meantime.
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'64 standard w/2.0L type 4
'62 bug

[Krustybus]

Gas cap not venting?
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Tim

[don.ville]

[nate9871]

It was the gas cap!!

A couple years ago I added a cork seal from Wolfsburg west as gas was sloshing out.

I had no idea the tank had no other vent?

I removed the seal and all issues went away, I drove for several hours and it was perfect.

I don’t understand why this didn’t happen on the highway but thank you for all the responses!

[don.ville]

[nate9871]

[Eric&Barb]

Nice original gas cap. Might try boiling the cap in water to see if that will clear the vent inside of whatever crud is in it and most likely glued there by old fuel varnish.
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[Culito]

I always forget the simple stuff.
Where does the venting occur? Around the outside edges? Maybe the gasket OD is too big?
_________________
© CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug

[Eric&Barb]

Venting goes from inside where the locking tabs go inside and outside of the gasket. Gasket looks like it can not block off the entire outer inside edge of the cap vent there.
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[iamdonquixote]

[nate9871]

Still at a loss here. Years later and this issue is still not resolved.

It was not the gas cap, I spoke too soon. About 6 months ago I brought the bus 3 hrs back to the engine builder on a trailer as I had given up. He set the carb mixture, set the timing. He said one spark plug wasn’t sparking and he fixed it, but I’m not sure I believe him. Bus drove great when I got it back from him. No issues for a couple months.

Got the bus out today for the first time since winter. Behavior has returned. Runs good for the first 10 minutes. Then starts stalling randomly at stop lights. Sometimes it fires right back up immediately, other times I have to sit there at the intersection and crank for 5 minutes, but it eventually does fire back up.

Limped back to my house. It’s been sitting in the driveway for 45 minutes and still won’t start. I pump the gas and crank, it pops and fires for a second then dies.


Could it be a defective coil ? What are symptoms of a bad coil?

Could it be this pointless distributor?

I don’t know what to do anymore other than to just start replacing everything aside from the engine block

[nate9871]

[nate9871]

Do I even have a condenser on this distributor?

[Stocknazi]

Try swapping the electronic "upgraded" ignition components with original German points/condenser.

Hole too small in aftermarket fuel pump stand? Sheesh, never heard of that. It's probably made from plastic instead of real Bakelite so it expands/contracts differently. Try swapping in an original unit.

It's times like these that makes me appreciate the boring reliability of a 019/050 and PICT-30.
Hope you find out what the issue is. It may not be a fuel delivery problem; it could be ignition.
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[iamdonquixote]

its been my experience that intermittant issues are generally fuel related.

[Venice Motor Bikes]

My thoughts are, it's either fuel or ignition!
Too much or too little fuel pressure?,... (install a cheap fuel pressure gauge to see).
Maybe the idle jets are the wrong size?
Replace the coil & install points, & also install the correct spark plugs.
Make sure the valves are adjusted properly for the type of pushrods that are in the engine. (do you have chromoly or aluminum rods)?
Check for vacuum leaks that could be opening up as the engine expands from the heat.

Report back.