Help! Engine's Buggin me!

[silverfox]

I'm driving a 71 Bug which had a really bad engine when I got it. I had the engine re-built to a stock 1600 longblock about 3mths back. Everything was running smooth till servicing a few weeks back. Now it has these random bouts of 'choking' that gets me really worried. When it happens the engine trembles & sputters violently and the whole car jerks wildly. It kind of feels like the engine is being choked of oil/air or whatever. This happens at almost any speed, most noticeably when driving long distances. And no matter how hard I step on the pedal the 'choking' still continues (even at full throttle), and the engine has no power and feels like stalling even though it doesn't. At idle, the engine sputters occasionally and could cause a stall (happens usually while waiting at the lights or in a jam).

My mechanic told me it's a bad carb. I'm using a Bocar 34pict-3. The carb probably was a little faulty as it seemed to be leaking quite a bit of fuel at the gaskets. He opened it and found it wasn't shut perfectly at the seams due to some of the internal pins not fitting right. He did some filing to solve the problem. But after installing it back the engine problem was still there. I also thought it sounded kinda rough using the Bocar. No matter how he tuned it, the problem would still be there.

I just ordered one of those German carbs from Aircooled.net and had it installed. This carb seemed smoother and more responsive (at least it doesn't stall now). But after driving it around I found the problem was still there. I'm convinced it's not a carb problem even though the mechanic still suspects so. I mean what are the chances of me getting one faulty carb after another (they're both brand new not rebuilt!).

For the moment I'm stuck till after the festive season. He's promised to strip the engine and examine everything all over again to see what's wrong. It's still driveable but it's terribly annoying when it happens which is getting pretty often. I've been popping in & out of the workshop every couple of days. Any ideas as to what could be the cause?

[Erik G]

check your elecrical connections at the coil, sounds like a loose connection to me
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[sixtee1 deluxe]

check all your connections on the coil and the dizzy. Are you using points or electronic ignition?

[Airsick]

It sounds like you need a more reputable mechanic, someone more familiar with ACVWs. Where do you live? Maybe someone can recommend one.

[Old Ben Gun]

I have had this happen. Turned out it wasn't the engine at all but the fuel filter. It even looked clean. It wasnt though and once I took it off I couldn't even blow through it. I also pulled the tank because thats where the crap was comming from. I also found a partialy pluged up finger strainer inside the tank fitting.

[silverfox]

I checked the electrical connections. They all seem tight and in place. I'll probably get the fuel tank checked next.

I was wondering, is there anything in/around the pedal area that could affect the engine?

[silverfox]

Just got it in to the workshop today, seems the it's the manifolds that's giving all the trouble. It seems to be leaking from several places due to a bad casting. It'll have to be replaced. Any recommendations for a good manifold?

[3Bugs]

The advise on checking the gas path is a real good one. The Keep your VW Alive book also describes cleaning out your main jet in the carburetor bowel, make sure you do that in case crud made it past the filter and the pump or was left in there from the factory.

Further:
Before I start changing castings I would make sure your problem is not the assembler first. If the manifold was working before the service then it probably is not the manifold unless you took a hammer to it or something. I would get a can of carburetor cleaner and while the engine is running spray a little wherever you have a connection; carb to manifold, boots connecting the center section to the end castings, and where the end castings are fastened to the head. If you get any change in RPM you have a leak, try tightening it up and spray again to make sure you got it.
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3Bugs
Well, actually a 67 Bug, 72 Super, 61 Ghia and a 2004 Beetle Vert (sorry)

[george4888]

Hey Dude, sounds like you need to find a better mechanic. The first thing I check is the fuel pressure and volume. You can have just enough pressure, but not enough fuel flow and the engine will do exactly what you are describing. Just because the gas tank shows full, does not mean you have enough volume of fuel going through the lines to feed the amount( not pressure) of fuel to the engine that it needs. The new carb was an improvement over the Bobcar( also known as junk) but you need to check the fuel flow. What about the fuel pump. Did anyone do a fuel pressure and volume test on it?? Later, Dude. ---George

[silverfox]

Just got my car back from the workshop. Turns out it was mainly the manifold. Did the spray test using carb cleaner and found leaks at several spots! Just my luck to end up with such a crappy manifold. It was leaking from the casting seams at the center section as well as the boots. My engine casing was coated with a layer of fuel because of that. They also found that the contact points were fried. Those had to be changed and also the condenser & spark plugs. After that they did a valve clearance too.

The engine seems to be running a lot smoother now. I sure hope this is the last of the problems.

george4888: Yeah, the Bocar does seem like crap now compared to this German carb.