1991 Yamaha 200hp 2000-3000 rev limits

I am workin on a 1991 Yamaha 200hp outboard motor. 2 stroke. pbs oil system, The oil tanks were removed and now is being premixed. Always ran fine when motor was transfered from one boat to another no its in safe mode and hit revlimiter at around 2000-3000 rpm. i am stumped been through almost everything. at the bottom of the computer on the left there is a plug that used to go to the oil float assembly on the main oil tank on motor now thats disconnected i know that when the oil is low it sounds alram and reduces rpm but since the tank is gone....? i know also a overheat sensor will cause reduction in rpm how do i properly by pass this oil system to trick computer? how to i rule out the possible bad overheat sensor?

Just a possible thought.. You mentioned it had worked before on other boats. The tank being disconnected should not be causing the problem as it should be reading an open circuit which is consistant with oil levels being full. I believe on the 200 2.6l models the oil control unit is internal to the cdi box, therefore fooling it should have been accomplished by the tank & sensor disconnect. There is also an oil switch operating at the trim sender so when engine is tilted up 30 degrees or more, oil will not run into engine and most likely if run will drop off rpms. Maybe, just maybe this switch is going or gone bad after moving it around so much. If you can find it, disconnect it and retry.
Sorry I don't have any literature in front of me to better direct you, hope this might help. Best of luck// DT

)))))

Sorry goofed on the last message. Forgot one thing, there maybe a pink wire between the CDI and the warning horn somewhere. If cut, any rpm reductions or warning horns should be gone. This wire ties them together. //dt

Hey Dtech, i also check the trim sensor. It is broken when trim downed the tab that sdhould be held down is broken off. If i CUT that pink wire coming out of the middle plug will that be ok and shut off rpm reduction?

Yes. This should be correct. But, final judgment is yours as I am only taking an educated guess as I do not have the exact manual for that motor. I figure it couldn't hurt to try as you seem near wits end with it..
Make sure to cut it in an area that is easily repairable just in case, thats all.
If this does not work the broken switch will need replacement or be put in closed postion somehow. This might also may be achieved by splicing of 2 wires on the switch, I will try and check on that one though..


Keep me posted.. //dt