2000 Mercury Optimax 200 hp - loses rpm's

[rptm4353]

I have a 2000 Mercury Optimax 200 that loses approximately 400-500 rpm while running at 4400.
This occurs infrequently after running steadily for 30 minutes or so. It will pick up rpm's on its own then drop about 400-500 on its own. Increasing the throttle to full will not increase the rpm's. I do not have a full filter in line and see no water in the fuel. Could this be a coil or powerpack issue? is their anyway to check the coils or powerpack?
Any suggestions or comments on what the issue may be and what to do?

 

[joshlee1973]

Re: 2000 Mercury Optimax 200 hp - loses rpm's

Did you ever figure out what was wrong with your Opti? My 2009 250 has the same symptom you are having. Please help.

Josh

 

[rptm4353]

Re: 2000 Mercury Optimax 200 hp - loses rpm's

Did you ever figure out what was wrong with your Opti? My 2009 250 has the same symptom you are having. Please help.

Josh

I followed the advice of a Mercury mechanic. I removed the thermostats and cleaned them and replaced the spark plugs.
He listened to the fact I had been in very low water and ran through sand and mud the day this occurred. Noted that the cooling water flow was probably restricted and may have heated up enough to foul the plugs.
This solved the problem! Good luck!

 

[rptm4353]

The problem was a bad injector.