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Mariner 3-cyl 90hp idle

F

FiveStar

Contributing Member
Hi guys,

What do you think of the idle here? This engine is circa 1988 I think. I reckon it's rough, but this is the first time owning one of these. It has brand new plugs in it. Comps are all even at 100 +/- 2.

Sorry for the angle: https://youtu.be/hq5XbMuSdJM
 
Seems to have a little "hitch" in it - seen worse.

Maybe pick up a can of Power Tune from a Merc dealer - costs under 10 bucks - just follow the instructions on the can.

If that don't help then the carbs may have to be stripped down and cleaned. If it's been sitting for a bit they may have "cooties".

All in all, if it was laid up, it's not sounding all that bad - certainly nothing immediately apparent that would be an issue.
 
28 year old motor...I would check the spark and make sure all plugs will fire good at 7/16 inch....change the water pump...change lower unit oil...try the power tune as Graham suggested but if it misses at higher rpm then rebuild the carbs....and I would not run it excessively before I did it...with the good compression you have a good engine in all probability so why take a chance on damaging it?..carbs are a good winter time project..
 
Yep, thanks guys. Can't say the Power Tune helped too much but damn did it smoke like a mother. It's still shaking quit a bit.
I live in Aus so we a in the midst of summer here.

I did the water pump, thermostat (which was missing) and the mechanic (a Merc spe******t) is coming to check the carbs. I'm not going to attempt to mess with those. I'm not confident I can successfully reset everything after pulling them apart and reinstallation. Lets see how we go. Will update you all.
 
My mechanic adjusted the carburetors and now she is purring like a sweet kitten. He said they were seriously out of whack.
 
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