I have an 87' 30 horse yamaha that has been giving me problems. the warning light turns on when ever i run at half throttle or less. if I run wide open it runs great, smooth and strong but as soon as I slow down or let it warm up that light turns on. I had a friend say it may not be getting oil any thoughts on this. I saw in another post people saying to bypass the oil injection and premix is this a good idea and what would the mixture be.

thanks

Bypassing the mixing system and adding the oil directly to the gas is exactly what I do on my older Merc.

Sounds more like a water pump problem than oil.

i replaced the impellar is there more i can do. the motor "pee's" but its not a very strong stream. the water isn't hot coming out.