New Motor Runs Rough Below 2000 RPM

[stolzeraj]

I installed a new 90 HP Mercury 2-stroke on a fish and ski, and it starts easily and runs well above 2000 rpm. Below 2000 rpm, it runs very rough. I doesn't want to die, but it shakes everything in sight. Does anyone have any suggestions for smoothing this thing out?<br />Thanks,<br />Biplane

 

[Barnacle_Bill]

Re: New Motor Runs Rough Below 2000 RPM

If you are sure you are using fresh gas, take it back to the dealer. You don't want to screw up your warranty.

 

[stolzeraj]

Re: New Motor Runs Rough Below 2000 RPM

Actually, it does not have a warranty (long story). But it's a good motor and I installed it properly. Could it be the mixture adjustments below 2000?

 

[Bob H.]

Re: New Motor Runs Rough Below 2000 RPM

Could be just some crud in the low speed jets. Try some carb cleaner like Chemtrol B-12 in the fuel.