Opti Max: violent shaking at higher rpm

[ddiwik]

i have a 1999 200 hp Mercury Opti-max. the engine starts and idles fine. it takes me about 20 minutes to get out of the marina area and once i hit the throttle and exceed 3500 rpm the warning light goes off and the engine begins to shake violently. when i pull the throttle back to below +/- 3000rpm the warning light goes out and the shaking ceases. After repeating this two to three times, the engine will run fine at higher RPMs. for the rest of the day. the next day i will have to repeat this process all over again. Thoughts?

 

[racerone]

Dealer can hook it up and check what may be happening.----Has compressor been maintained ?

 

[ddiwik]

this problem began last summer where we hooked up to computer and changed, plugs, impeller, O ring and air compressor. Took it out in mid May for a quick run with no problems...came back two weeks ago and same old problems...because after a few "false starts" (e.g. alarm and shaking) she then runs fine i am thinking it has to be something that for whatever reason corrects itself. Love to hear any thoughts one might have

 

[ddiwik]

also, i am wondering if water and/or air is somehow getting into the system in trace amounts that its only noticeable at higher RPMs and somehow after a few "false starts" the air/water is removed from the system until she sits for some time...i know that i am grasping at straws but its been a very costly exercise in trying to figure out the problem(s)

 

[ajgraz]

I think that a small amount of water in your fuel is a definite possibility. (If it was A LOT of water the motor would just plain shut down).

Do you have a water separating filter?

 

[ddiwik]

i do have a water separating filter but have yet to check it this season