Johnson 140TL79R top two cylinders not firing

I have a Johnson 140TL79R on which the top two cylinders are not firing but have spark. I know very little and have no manual, it has been suggested to me that the starter solinoid might be cactus is this correct? and or what else should i be looking for?

Re: Johnson 140TL79R top two cylinders not firing

Welcome Jim!<br /><br />A question or two....when you say the cylinders are not firing but have spark, does this mean that when the engine is running the spark quits or it seems that they are not getting fuel? What do the spark plugs look like after running and kind are they?<br /><br />Is this a new engine to you or did this problem just occur? If this engine is new to you, has it been setting for a long time?<br /><br />Have you taken compression readings on all cylinders yet? Would be a good place to start. Will give you an idea as to what shape the cylinders are in. And check the spark again to each cylinder. The sparks should be able to jump at least a 7/16" gap with a hot lighting like spark.<br /><br />I know....lots of questions. But knowing the above will help. A service manual would help you a lot.

Re: Johnson 140TL79R top two cylinders not firing

OBJ,<br /> Thanks for your response no the engine is not new to me but it has been sitting for 8 months to a year i have replace the plugs with the same ones that came out of it which were DENSO K20PR-U 11. I checked the compression a few weeks back from memory one was little low maybe 20 psi.<br />When the engine is running if i pull the leads from both of these cylinders there is no apparant change in RPM but when i check spark with screwdriver on the block there is still spark.<br />I have also pulled the top carby and blown it all out is there a better or alternative way to clean it?

Re: Johnson 140TL79R top two cylinders not firing

First thing is to get the correct plug for the engine which is a Champion UL77V. <br /><br />You may not be getting fuel to the two top cylinders. The upper carb is common to both cylinders. Just blowing them out after setting for so long don't always do the job. What you want to do is soak the carbs in carb cleaner and follow up with choke and carb cleaner in a can blowing thru all the passages. Then follow up with compressed air. I would install new kits also.....OEM prefered.<br /><br />Here's something to try, put some fresh premix fuel in a spray bottle. Take the carb cover off and start the engine. While she is idling, spray some premix in the top carb throat and see if the engine idle smooths out and rpm picks up.<br /><br />Is it idling smoothly and at what rpm? Throttle plates closed all the way?

Re: Johnson 140TL79R top two cylinders not firing

OBJ<br /> Cheers i will try then get back to you on RPM etc