Running Rough. Misfiring and Running Rich

[Gabe]

Recently fixed a stuck valve problem. Now have consistent compression across all 4 cylinders ~80. Engine runs very rough. It sounds like it is misfiring. Plugs are very dark and sooty and it starts with little to no choke indicating running rich. Not sure if the rough running is a result of running rich, or if it seems like its running rich because of the misfiring.

I have cleaned the carb thoroughly, replaced the points and condenser, new spark plugs, adjusted timing by rotating distributor. Condition improved a little, but is still bad. I am all out of ideas now. I was assuming fixing the stuck valve would have solved the problem, but apparently not. Thanks.

[Marian Claire]

Do you have the adjustable main jet? Are you sure the plug wires are in the correct order and in good condition? Good strong spark at the plug end of each wire. Are all the plugs sooty? Even new plugs can be bad. What plug and gap do you have? Dan S/V Marian Claire

[Gabe]

Fixed jet. Plugs gapped per manual. Plugs are sooty after running.

[Dave Neptune]

Double check

Paul, if all is fresh and even close to correct the engine should run fine. I would take a good look at the plug wires to be ABSOLUTELY sure the firing order is correct.

When you adjusted the distributor did you have a load on the engine or not?

How long has the engine been running since the valve issue? The valve could still be acting up a bit but if the compression is CONSISTENT I seriously doubt it is the valve.

Is there any fuel leaking out of the throat of the carb? Also be absolutely sure the choke is opening after you get it started.

Dave Neptune

[hanleyclifford]

What gap are you set at on the points? Do you have a dwell meter?

[Marian Claire]

Was the engine showing these signs, sooty plugs, before you unstuck the valve?
Is this after running at idle speed? If so try adjusting the idle mixture screw out a bit to lean out the mixture.
Check each plug wire for good strong spark.
Did you use TDC #1 to position the rotor and the wiring order?
Dan S/V Marian Claire

[Gabe]

Points were gapped according to manual. Put new distributor cap and plug wires on. Verified firing order by checking rotor position with TDC. I didn't adjust distributor under load I will try that. There is a lot of valve tapping sounds coming form head while it runs.

[Sony2000]

Carbon is the killer of those valves. Go more aggressive on leaning the mixture. Up to 4 turns (like me) if it doesn't run worse. Add a carbon cleaner in the oil, and in the gas, and run the engine. It will get better.

[Gabe]

Tried to take the boat out yesterday. No power in gear. Limped back to the dock and inspected the prop...covered in barnacles. Cleaned the prop and the engine is running much better. Still sounds like it misses occasionally and am still hearing the valve tapping. I will run it as much as I can to try burn off any carbon build up. I have noticed that my engine runs cool....around 120. My understanding is that this will contribute to the carbon build up on the valves correct? I guess that will be my next problem to tackle. Thanks.