Hesitant 1972 Bay

Two major items:

carb accelerator pump jet. Hard to check on a '72 since you can't look down the carb throat. Might have to remove the carb.

manifold heat. The smaller pipe under the manifold. After a 10 minute run, feel both ends of the small pipe. Both ends should be hot enough to burn your fingers. If only one end is hot, the heat is not working and will cause major stumbling problems.

Timing, spark and vac leaks are also possible causes but my money is on the first two.

Speedy Jim

"I have no use for a car which has more spark plugs than a cow has teats!" Henry Ford, when advised that Chevrolet was introducing a 6-cylinder engine.

Cheers Speedy

Do you think it could be the pump jet? As if the engine is revving at say over 3000rpm, and I floor the throttle it picks up straight away so it

*seems* like it is working, it is only at low revs there is the problem.

I did not think of the heat issue, it has certainly been cold here lately in sunny South Wales! Will check this as soon as I can.

Timing is spot on, and pretty sure spark is good. Will let you know what I find.

Thanks Jim

You never mention what kind of distributor or carburator you have...if it's a 009 and 34 Pict 3, that's you're problem right there. Forgive me if I'm way off base here.

By the way, how's that 1600cc do in a bay window? I'm in the process of swapping a type IV into my Beetle and its 1600 into my friend's bay window.

Peace, Harry

It is an 009, not sure of the carb, though I do believe it is the original. I have not long had it and I am used to Beetles with 1776 motors and Dellorto carbs :) But it never used to be hesitant, it used to drive really well. I was quite surprised how nicely it pulls the big old bus around.

Have not had chance to give it a good run out and check the heat risers on the manifold yet, but I pulled the carb off and checked out the accelerator pump and this is working fine, a nice squirt of fuel coming out of it every time.

One other question, I adjusted the valve clearances today by setting the pulley to what I thought was the TDC mark, but now I am thinking that it may be the 5 degrees atdc mark. Will this make much difference to my valve clearances?

The cam lobe is quite broad at that point, so being off a few degrees doesn't really matter.

Jim

That's good to hear. My 1600 is a Mexican replacement engine that came to me with a 009 and 34 Pict 3. It would serious bog down off idle until I put the "005" SVDA distributor from the 2.0L type IV onto it. Now it pulls much much better on the low end. Probably not ideal, but definitely better than the 009. When/if we get this 1600 into the bay window it'll probably wind up with a better carb and exhaust, so I think the performance should be satisfactory around town.

Anyway, that doesn't really explain why you would go from okay to crappy. Checked out the rest of the ignition real good yet? The condition of the points, the dwell, maybe even the coil could cause problems like this. Also, how's it idle? Maybe a clogged idle jet? Just throwing ideas out here.

Good luck, Harry

Great, I didn't fancy doing them again. On cylinders 3 and 4 all the valves were very loose, about 10 or 12 thou! This was not helping the way the bus was driving either. I will hopefully get a chance to take it out tomorrow, and then I can see how it goes and then also check the heat risers.

Thanks again Jim

The only thing I have not checked out is the points and condenser (coil is pretty new). I am going to get some new ones as soon as I can for the sake of a few pounds. Once it has warmed up it idles absolutely spot on. It did have some VERY loose valves when I checked them today so I have set them all now to 6 thou. I will try and get it out on the road again tomorrow

Cheers Gareth

Checked the manifold heat today and the left hand side was very hot, the right hand side not so hot. Just warm really. So this is causing my manifold to ice up? After adjusting the valves the other day the bus is driving slightly better, but how much of a hesitation will the 009 dissy cause? Will replacing it with a vac advance dissy really make that much difference?

Could not see any obvious manifold leaks. I sprayed some wd40 on the rubber boots and could not spot anything bubbling away there.

If one side is warm, it's probably working a little bit. The heat is not there to control carb icing; that's another issue.

With an 009, you have to accelerate "gradually". That's key.

Jim

I had noticed that. It does pick up quicker if I try to ease the throttle down gently rather than flooring it. What is the heat there for then? I always thought it was to stop the carb icing.

The heated *air* introduced into the air cleaner is there to control icing. The heated manifold is to produce a "hot spot" in the manifold to vaporize raw fuel dumped in by the accel jet.

There is a brief discussion here (written for watercooled cars):

Jim

Ahh, thanks Jim. You learn something new every day!

So can these small pipes to the manifold be cleaned out to help things? Do they get full of carbon or something? I do not have the original air cleaner on there, so I do not have the luxury of heated air. I have a nice little chrome filter that does not take up much room. That is probably the only good thing about it though, it probably does not do much for the engine. Maybe I will try to get hold of an original filter housing.