1990 50hp Evinrude Problems?

[oldgradywhite]

I have a 1990 50hp johnson with a running problem. I rebuilt the carbs and it was still running poor it has to be at high idle to run at all. when I was running it I pulled the top plug off and it ran the same is with it on. so I pulled the bottem plug and it died. It is not firing on the top cylinder. well only once in a while with a misfire. I checked the resistance the top coil was at 4.2 the bottem 3.5 meter set on resisatance x10. Is there something beside the coil that can cause a misfire on cylinder one? I know my motor has S.L.O.W but I don't know how that works? could it be a stator? My clymer manual isn't very helpful? Is there other tests? thanks

 

[SparkieBoat]

Re: 1990 50hp Evinrude Problems?

check engine compression, the do a spark check on each coil with a spark gap tester set at 7/16 gap..to test stator you will need a DVA adapter and a multi meter.

 

[oldgradywhite]

Re: 1990 50hp Evinrude Problems?

enigne compression is 138 top 132 bottem I have check spark but its with a spark tester but the top spark is not consistant. Jest a random spark here and there. I have a muti meter but no dva meter

 

[SparkieBoat]

Re: 1990 50hp Evinrude Problems?

cannot trouble shoot electrical on an outboard without a DVA adapter..they about $30..google it. yu will never regret having on..or you could just start replacing parts starting with the cheapest one first..probably start with coil. also check and make sure your coil ground is clean.

 

[oldgradywhite]

Re: 1990 50hp Evinrude Problems?

I believe that to check coils all you can do is a resistance test which you can do with a muti meter?

 

[SparkieBoat]

Re: 1990 50hp Evinrude Problems?

you can do OHM test but they are mostly unreliable..but they will work sometimes. bets way is to check voltage going in with a DVA adapter. they are cheap enough and very useful once you get the hang of how to use them.