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25mercelectricstart89 does not idle and low power

V

van123

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"My 1989 merc electric start s

"My 1989 merc electric start seems to idle really rough and hard to keep running at idle out of gear. Also, the motor seems to me to be running on one cylinder. Is this possible. Any thoughts....Also does not seem to have much power to me compared to my previous 20 hp motor that I used to use on the same boat. Any quick and easy check to make sure it is firing on both plugs? I noticed that one plug shows no carbon and the other shows plenty of carbon. Maybe I've answered my one question but am really really engine dumb! Thanks for any comments. Van, Medford, ORegon"
 
"Van, we can guess all day, so

"Van, we can guess all day, so you need to start with some basic troubleshooting.

Check the compression and then check for spark at both cylinders.

You are looking for about 100 psi at both cylinders with neither reading more than about 10% different than each other (ie, 98 and 104 would be acceptable).

If you have strong blue spark at both cylinders, then you know the ignition is working properly (or obviously not working).

If compression and spark is ok, then it's off to troubleshooting the fuel system...."
 
Thanks Graham. Although I am

Thanks Graham. Although I am not a motor king of guy I took your advice and pulled the connections off on the electronics module and cleaned them all up nice and shinny and also cleaned the interior of the spark plug connections. The engine started immediatly and ran smoothly. Took it out to the bay today here on the Oregon coast and had lots of power. Sure appreciate your comments which supplied me the encouragement to take a swing at the motor. Best regards. Van
 
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