2001 Suzuki DF40 4 stroke coughing

MichaelP

Lieutenant Junior Grade
Joined
Apr 26, 2010
Messages
1,190
Ran into a bit of trouble this weekend. At first start it wouln't go above 4000 rpm but it finally worked out of it then started what sounds like a miss fire every 5-10 seconds and the rpms bounce 100rpm and will eventually stall at trolling speed. The fuel has been sitting for almost 3 months but it's heavily treated with marine Stabil. I swapped tanks and ran fresh fuel @ 2000rpm in the yard for about 15 minutes and no change. Then ran seafoam at the rate of 2 oz /gal at 2000 rpm for an hour and saw a small improvement. So small I'm thinking it may be just wishfull thinking. This motor has always run well and the primer bulb was always soft and still is so I kept a hand on it while running and made sure it stayed hard and it had no effect. Even disconnected the fuel line from the engine while running an again no effect. Now I'm thinking it may not be a fuel issue. No manual yet so I can use some help before I take her in. Not much has been done besides oil changes.
 

MichaelP

Lieutenant Junior Grade
Joined
Apr 26, 2010
Messages
1,190
Re: 2001 Suzuki DF40 4 stroke coughing

Changed the plugs and she is back to normal. Not sure if it was the sea foam or plugs.
 
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