Help for a 1991 50HP Merc ?

elfrod

Recruit
Joined
Aug 20, 2011
Messages
4
1991 Merc 50hp is stalling at low (trolling or idling) rpms. I think the fuel/oil mixture is too rich... seems to be burning a lot of oil. Motor used mostly for trolling, and used to do well at 1.5 mph, but now have to go 3mph to avoid stalling. Anyone have any advice; know how to adjust mix ??? Or does it sound like an idle adjustment issue? :facepalm:
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: Help for a 1991 50HP Merc ?

If you troll a lot, the combustion chamber could be gungied up. Get a can or two of Sea Foam at your local auto parts store. I'd double up or triple up on the recommended dosage on the can for the first couple of tanks of gas. Then you can drop down to the 1 oz per gallon or just keep it where you are. I keep in in my tank and have stellar results.

Also, being hot weather, you may need to up your idle set screw a tad. I had to do mine. I run ethanol (all you can get) and It might be fuel type related.....never had to do this before.

Mark
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: Help for a 1991 50HP Merc ?

again, i would do a decarb on your motor

if that does not solve your problems then you might have to go and readjust your idle jets and readjust idle to compensate for the weather changes. cold to hot, hot to cold.
 
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