1984 johnson 115

[culpster]

I have125 lbs of compresion on each piston. I had the carbs rebuilt and the spark checked. Spark is great , comp. great, carbs great, but the bottom two pistons wont fire. Does anyone have a suggestion. Mechanic also said valves look good visually. Help

 

[plywoody]

Re: 1984 johnson 115

If I were you, I would go back to all those things you checked and check them again.<br /><br />If the problem is with two cylinders not firing, something among the spark/fuel/compression combination is not "great"<br /><br />Perhaps your engine simply defies the laws of physics and chemistry somehow, and even though it gets fuel, compression, and ignition, it just doesn't ignite--but somehow I doubt it and something somewhere is not "great"

 

[Solittle]

Re: 1984 johnson 115

When you said you had this stuff checked - I assume that you had a mechanic or friend do it - did you watch to verify? Does not really matter as your next troubleshooting steps are the same no matter who did what. You need to find out if those two cylinders are getting both spark and fuel. Check for fuel by looking at the plugs. If they are drenched with fuel get a spark plug tester and check for spark.

 

[Joe Reeves]

Re: 1984 johnson 115

Culpster.... You say that you had the carburetors rebuilt, but having both bottom cylinders dead would indicate that since they are both fed fuel via the bottom carburetor, the fixed brass high speed jets (2) in that bottom carb are clogged, or the bottom carb is not being supplied fuel for some reason.<br /><br />Fuel, if within the bottom carb, must flow through the high speed jet(s) before it can flow to any of the other passageways.

 

[BKool68]

Re: 1984 johnson 115

Joe is right in what he says. Check the bottom carb.