hi,im new here,and have a mystery problem.

[lunatic]

hi everyone.
ive got what seems to be a mystery problem with my 20hp 1990 johnson pull start.
i bought the motor used,heard it run,it was a cold start and it sounded good. bought it in the winter so it sat until i went on vacation in the summer. when i got up there i launched the boat,and it started on the 3rd pull and i drove it to my dock and tied it up. about 2 hours later took it for a quick rip (15 min) ran great.next morning wont start. not even a slight catch. it was getting fuel so i figured spark. used the trolling motor and the batt died. i must have pulled that chord 100 times, no joke and once it sputtered slightly,but never again. when i got home,i cleaned the plugs,and tried again. no spark. tested the kill switch with ohm meter. works. replaced the charge coil,it has spark.pulled it 4 or 5 times and all time its sparked,cool. a few days later a day before a trip i try,no spark.replaced power pack. no spark. check all the wires. all are good.the charge coil and power pack are new and OEM. whats left? very frustrated! any ideas?

 

[lunatic]

Allways go back to the beginning check the compression first allways. How are you checking for spark you must use a spark gap tester it must jump a gap of at least 3/8 inch brite blue snap. Get back to us with the results of those two tests and we can go from there.

i did it the way ive tested cars for years. screw driver in the plug wire up against metal. it showed i had spark a few times when the charge coil was replaced but when i went back to make sure before heading out days later there was no spark. also pulling the spark plug out and leaving it in the plug wire is another way ive tested when i was alone.
as for compression,im trying to remember if i did a test or not. it was months ago, im pretty sure i did and all was good. even with poor compression it should at least sputter. the ONLY thing not replaced are the 2 coils. i just cant see 2 coils going at once,that would be just crazy.

 

[joereeves]

Compression gauges are cheap as are spark testers.... any automotive parts store.

Poor mans spark tester... #2 philips screwdriver inserted into the spring connector (inside the rubber boot) that normally connects to the spark plug, then hold it 7/16" away from the block for the spark to jump... just takes a steady hand of an accomplice.

If you have compression, spark, and fuel... it's got to run, UNLESS the flywheel nut wasn't torqued to factor specifications and has ressulted in a sheared flywheel key. Even a slightly sheared key will throw the engine out of time... you'll still have spark BUT at the wrong time!

Another problem you may have encountered is that debris has broke loose (debris due to sitting) and clogged the carburetor jets/passages... best to clean the carburetor and manually clean the high speed jet.

 

[lunatic]

thanks for the suggestions. "poor mans spark tester" is exactly how i was doing it. the flywheel nut was tourqed to factory specs.
because of a bad cold snap here, it will be a few days/weeks before i can get back to it.ill have to re-check all grounds and wires. i have a compression gauge.ill re-check as well incase i didnt in the first place. i have another motor but its a 56 evinrude id rather not use lol and that might be the motor i did the compression check on.
the timing suggestion doesnt make much sense to me,as the motor ran like a champ and started on 3rd pull after sitting for close to a year. ran a few hours after that great. next morning nothing. not even a slight hint or sputter. its pulling the chord and over n over and not getting anything.zero spark.