Michael B Smith
New member
I have a very erratic issue with my Optimax 150 (2 stroke, fuel injection). Overall runs perfect with one exception. Probably on average of once a day, when I shift from forward back to neutral, rather than returning to the normal idle of 650 rpm, the motor accelerates to what I will call a "high idle" of around 1100 rpm. The motor will not return to the normal 650 rpm once it does this. The only solution I have found is turn the engine off and restart it. Then it returns to the normal 650 rpm. This happens maybe once very 50 to 100 shifts. We have replaced the throttle positioning sensor and this did not correct the problem. We have also checked the hot foot for a bad spring but the issue does not appear to be related to the hot foot. I have had a very reputable Mercury mechanic look at it and of course he couldn't get it to do anything out of the ordinary in his shop out of the water. He also ran various scans with Mercury software and everything showed to be normal. Anybody have any thoughts?
