Engine no run

JohnB15632

JohnB15632

Well-known member
Wednesday afternoon, my A engine ran pretty well it ran well for almost 15 minutes and then just quit. I can not get it to run again.
Today, a fellow club member came by to help.

We were able to verify,
1. The battery is fully charged at 12.32 V
2. We could verify that we had a strong blue spark at the spark plugs.
3. We could verify that we had a strong fuel flow to the carburetor.
4. We checked timing, it was spot on. Point gap and spark plug gap were checked and verified.
We could not get even a cough or fart.

Thoughts?

Secondly, we did a compression check. Cylinders 1,2, and 3 were measured at 52 psi. Cylinder 4 measured 0 psi.

I do no know what to think about this.

Help please?
 
You have to find out why #4 Cyl does not have any compression.


It sounds to me that it may have stuck a valve.


If so, it is probably an intake and I bet you can not develop any vacuum in the intake to draw the air/fuel mixture thru the carburetor.


If it is a stuck valve because the guide is too tight, it may unstick itself after it cooled off.


You may be able to see something by looking at an angle down the spark plug hole.


If not, you may have to take off the side cover and see what is going on.


AN adjustable lifter screw that is not tight can un-screw and not allow the valve to close all the way may also be the cause.


My opinion,


Chris W.
 
TerryH said:
Broken or stripped timing gear???
Click to expand...

He's got compression in 3 out of 4. Pull the valve cover off, you can see the valves. I concur with the earlier diagnosis, likely a stuck intake valve. Not a difficult thing to diagnose or repair.
 
x2. on stuck valve and try starting aerosol . S/plugs wet or dry after starting attempts? Pour fresh fuel into carb bowl? Tried a tow start?
 
It could very well have a stuck valve, but should still run. Apparently there are more than one issue.

You state there is spark and the ignition system is fine. I'm kinda sorta thinking there is a problem. Check to make sure it has the correct coil [or external resistor]. Check that the points voltage is not over 8v.
 
If you use ether be very very sparing. You will kill the spark plugs. I'd never use it. If you must use something, WD40 works better.
 
eagle said:
...if you use ether be very very sparing. You will kill the spark plugs. .... If you must use something, WD40 works better.
Click to expand...
How does ether kill spark plugs? Are you suggesting spraying WD40 into the carb [if so what part of the mix is explosive- the oil or the propellant?] or are you suggesting WD40 externally as water dispersant?
 
eagle said:
If you use ether be very very sparing. You will kill the spark plugs. I'd never use it. If you must use something, WD40 works better.
Click to expand...

Ether will tell you if the problem is fuel related or something else. It shouldn't hurt anything if used by the directions.
 
The coil should not be that hot. Are you using a 12 volt coil. It should be 3 ohms. The no compression has to be a stuck valve or bad head gasket.
 
1. I cleaned the carburetor inlet ball valve. It was plugged. The valve now works clean and great.

2. I put 2 tablespoons Marvel Mystery Oil into each cylinder. Two hours later I came back and gently tapped on the open valve in cylinder 4. It slammed shut.
I hand cranked the engine 5 - 6 times. All sounded good.

Super great day!!!!
 

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Patrick L. said:
It could very well have a stuck valve, but should still run. Apparently there are more than one issue.

You state there is spark and the ignition system is fine. I'm kinda sorta thinking there is a problem. Check to make sure it has the correct coil [or external resistor]. Check that the points voltage is not over 8v.
Click to expand...
The only problem here is the points will measure battery voltage when they are open, and they will be 0 volts when they are closed. You'd have to measure the voltage at the coil points terminal if you are using an external resistor and 12 volts.
 
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