Holley 94 on 8ba barely runs

[JRN1967]

I had a little time after work yesterday and checked my coil. I have 1 ohm resistance on the primary windings and 7.4K to the coil center. 12V on the negative going to the distributor, and my condenser tested good.

As Mart suggested I bumped the timing a little, but that only made it worse. So at this point I believe I can rule out timing, coil or distributor related.

I know the feeling of chasing my tail, and to avoid this any further I decided to take the advice of the majority and rule out the idle circuit. I disassembled the carb and left it soaking, when I reassemble next time I'll do a more thorough job so I can rule out a blockage.

Slamnslash - Appreciate your info as well. Knowing your jet and power valve sizes aren't way far off from mine. Your initial settings will help when I reinstall the carb for testing. I'll look into the fuel pressure later if the cleaning doesn't help.

I'll update this thread when I get carb back on.

[JRN1967]

After cleaning and reassembling the carburetor it will now idle. There's a stumble off idle and no power driving it around the yard. This is a model a project car, that gets backed out of the garage on weekends, so I can work on the other family cars and projects.

Someone mentioned doing a compression and vacuum test.

With the engine warm and running best I have steady 17.5" hg vacuum from the intake manifold. I set it with a timing light but it runs a little better if I back it off about 1/4" below the pointer.

Compression numbers warm and dry, all the plugs out and full throttle.
#1=105 #2= 85 #3=110 #4=115 #5=110 #6=100 #7=115 #8=120

Same test warm with a couple quirks of 10-40 oil:
#1=115 #2=90 #3=115 #4=120 #5=115 #6=110 #7=120 #8=120

#2 is considerably lower, but I'm not sure if my higher readings are lower than normal?

Some blow by when it warms up but not horrible.

I've read other threads here where people were able to drive around with worse numbers than mine.

My goal is to not get to deep into this engine until I get my other projects done. But I'd like to get it running a little better in the meanwhile.

[flatjack9]

Vacuum is low. Should have 19 - 20" hg. at idle. When you move the mark below the pointer, you are advancing the timing. Due you have the vacuum disconnected when checking the timing?

[JRN1967]

No flatjack9 I have it connected. Next chance I get, I'll reset it with the carb plugged.

I should add that I don't notice the timing dimple on the pulley going lower as I rev the engine. Maybe my vac advance has a leak?

Thank you - John

[flatjack9]

The venturi doesnt have enough flow to cause the spark to advance at no load conditions. So what you see is normal. Need to connect a vacuum pump to the can to see if it advances. Not unusual for these to go bad.

[Ken Henry]

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you should be able to see some advance revving it. Passages in the carb may be plugged

[Charlie ny]

JNR,
In lieu of a vac pump use your lungs. Rig a hose to the vac can and give it

draw. The can should advance the breaker plate. Next hold the breaker plate back in
its rest position, when you again apply suction to the can you will feel the plate trying
to move against how it is being held back. If you don't feel a good hard draw on the
plate then most likely the can is shot. Mac VanPelt is my supplier of choice for the vac can.
Charlie ny

[JRN1967]

Thank you Charlie ny. I was trying to figure out how to test the can without a vacuum pump.

[Ol' Ron]

Learn sumpin every day, till they throw dirt on ya.
Gramps

[Ken Henry]

While it is definitely essential to test the vacuum can, you can have a good advance can but no ignition advance if the tiny passages in the carburetor are plugged up. This happened to me years ago when I was first getting may car running after a long sit and it was a real dog with no ignition advance!! You should be able to see some advance revving in neutral because the signal to the vacuum can is a combination of ported manifold vacuum (manifold vac that comes in just of idle) and the venturi vacuum related to RPM/flow through the carb.. Ken

[JRN1967]

I did what Charlie advised and when I draw on the vac can, the breaker plate moves a lot, and will stay there as long as I hold on the draw.

Ken, I just disassembled this carb and believe I'll cleaned all the passages. I'll check again.

Is it possible that I've got a bad connection under the breaker plate? How difficult is it remove so I can inspect?

Ron, Can you look over my compression numbers? Cylinders#2 & 6 are lower than the rest, and maybe that's causing the hesitation and lack of power?

[Ol' Ron]

#2 is alittle low, but I don't think that's the trouble. Now try this. dis connect the vac advance. no need to plug anything. Now check the timing. pointer should be on the dot. Now advance the timing about an inch on the pulley.. This adds about 20 degs of timing. Now take it for a ride. Should run just fine accelerate and cruse just fine. It's like driving a Model A after you advance the timing. You could do this forever. However, starting the engine may become e a problem, and a jammed starter is a bummer to fix. But if you spinn the engine before turn on the ignition, it should fire right up. The only thing this proves is there is nothing wrong with the engine.
Gramps

[deuce_roadster]

Are you using compressesd air to blow out the passages in the carb when apart? Maybe you need to get a different carb from Charlie NY.
Have you checked for vacuum leaks between the intake to block with some carb cleaner while it is running?

[JRN1967]

Thanks Ron! I'll give this a try over the weekend.

[JRN1967]

Originally Posted by deuce_roadster

Are you using compressesd air to blow out the passages in the carb when apart? Maybe you need to get a different carb from Charlie NY.
Have you checked for vacuum leaks between the intake to block with some carb cleaner while it is running?

Yes I'm using compressed air. I did check for leaks with carb clean and didn't notice any difference. Vacuum readings idling is almost 18" so if there's a leak its a very small one.

[JRN1967]

After several hours of troubleshooting and research (here and elsewhere) I found the cause of my hesitation and lack of power. It was worn insulation on the hot wire under my breaker plate. I wasn't able to see it until I completely disassembled the distributor.

Thank you all that contributed, I really appreciate your help and advice.

[Ken Henry]

Nice work fixing it!

[Frank Miller]

Thanks for letting us know. This is a very common problem.