F4-134 problem

So, my 4-134 all of a sudden was stuttering at anything over 1200 rpm.

I did all the usual stuff, went through the points, plugs, even got new plug wires. Checked the timing etc. Nada..

I am no mechanic but a neighbor of mine is a shadetree and told me to check the cylinder compression.

1, 2 and 3 cylinders are all between 114-116 psi dry. #4 was 85 dry.

I put a cap full of oil in number 4 and re-tested it and wet it brought it up to around 100.

So my question is, does this sound like a ring problem? And I guess my second question is does anyone know a good place or person to fix this in the Colorado Springs area?

Thanks in advance for any input.

 

Sounds like a ring issue from what you've done. Does the vehicle sit without being driven? Could be rings are sticking in their grooves. Might try seafoam or marvel mystery oil down the cylinder and let soak for a day or two and see if it helps.


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yes, it does sit all winter, every winter, and this year, I have only had it out less than 100 miles since taking it out of winter mothballs before this started. Is your theory that maybe some varnish has developed and thus the rings are not floating freely and that seafoam or marvel oil may free it up?

I assume I would put this in directly from the spark plug hole.

Also, does cylinder #4 have anything to possibly to do with it? I.e. does #4 in the Hurricane get any less oil for some reason?

Thanks for your input!

 

No, but I have access to one.

 

Possibly a head gasket leak on #4.

 

Carbon can build up in the ring grooves. When a vehicle sits for long periods of time the carbon can harden up causing the rings to stick and not seal properly. The idea of marvel mystery oil or seafoam is that it helps soften the carbon up so the rings can free up. Yes, put it in the spark plug hole and let it sit. The. Crank engine over with spark plug out and ignition disabled. This blows out the excess fluid so you don't cause damage. Put a rag over the spark plug hole or you wl have stuff blown all over. Then put in spark plug, enable ignition, and start up. Be prepared for a bunch of smoke at first out the exhaust. Should clear up.


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Stuttering at high RPMs is typically a valve or ignition timing issue. A vacuum gauge like blevisay suggested could help pinpoint the problem. You do have a ring issue for sure but it may be coincidental and not causing the problem.

 

Let seafoam sit for 3 days, didnt appear to change anything. I am going to drain about a quart of oil and replace it with a quart of transimission fluid to see if hitting it from the bottom of the cyl does anything, I will run it for 10 minutes or so, then change the oil.

I am out of ideas other than that, if this doesnt do anything, I am guess I am back to my main question, anyone know of a place or person that can fix it.