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Any suggestions? Johnson 15 issues

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bruisedreed

New member
I found a little Johnson 15 (J15rcrm) last season that was too good of a deal to pass on. I never managed to get it running well enough to use more than a time or two last season. I am quickly getting frustrated with it and am a bit perplexed with the way it behaves. I believe the main issue has to be a sync/linkage thing. I have good compression, a freshly rebuilt carb that delivers fuel well and an otherwise proven fuel system, Good compression even on both cylinders and good fire. I can start the engine pretty easily when it's cold by choking and advancing the throttle plate past the mark to open the throttle a little. Once started it runs, idles and works fine. Once shut down it will NOT start again warm. I have tried to sync the carb per instructions aligning the throttle plate mark and tuning the cam follower but it won't start and run in that scenario. It will quickly fire but dies immediately. I am open to suggestions at this point.
 
Answering questions may help you.----Does spark jump a gap of 3/8" ( 1 cm ) on both leads ?-------What are the actual compression numbers ?-------Tried opening low speed mixture screw ?----Checked flywheel key ?-----Checked fuel pump diaphragm ?----Test run on another tank and hose ?----Water pump service done ?----Thermostat checked ?
 
racerone said:
Answering questions may help you.----Does spark jump a gap of 3/8" ( 1 cm ) on both leads ?-------What are the actual compression numbers ?-------Tried opening low speed mixture screw ?----Checked flywheel key ?-----Checked fuel pump diaphragm ?----Test run on another tank and hose ?----Water pump service done ?----Thermostat checked ?
Click to expand...

Should have mentioned...rebuilt carb and replaced fuel pump. 123 psi compression on both cylinders. Water pump and impeller are new and pump well. Thermostat is new, I have played with low idle but can't start the motor without the idle being set pretty high. Flywheel key is a great Idea. I will pull the flywheel and check that.
 
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