1979 Mercury oil injected 150

[Barnicle Bill the Sailor]

I am new to boating and now have a problem with my boat. The motor is a 1979 150 Mercury oil injected type. It was running fine and I was stopped with the motor running. After I went back on power something happened. Here is what I have going on. When the prop is not engaged the motor runs up to 5500 rpm just like normal. When I engage the prop, the motor runs up to about 1000 rpm and the boat goes very slow. I have looked at the prop and there is nothing rapped around it or anything I can see that would drag down the motor. I was thinking that I may have spun a prop hub but I would think that the rpm would still rise and the prop would just not spin. If anyone has an idea, I would appreciate it.

 

[LubeDude]

Re: 1979 Mercury oil injected 150

First off, Welcome to the forums.<br /><br />Second, NEVER rev the engine like you are doing without the prop ingaged, You can have a run on where the engine will take off and you cannot stop it from over reving without choking it out or it runs out of fuel, turning the ignition off will not stop it as it goes into a dieseling cycle.<br />Third, It sounds like there may b some linkage problems, check to see if you are getting full throtle movment.

 

[Barnicle Bill the Sailor]

Re: 1979 Mercury oil injected 150

I checked the throttle linkage and it was good. The only other thing is that the fuel was and still very low right now and I was just thinking that It may be that the motor is buring more oil than gas. Could that be the problem.

 

[jimmbo]

Re: 1979 Mercury oil injected 150

Just for the record, Mercury didn't add oil injection until 1984 or 85.

 

[KCLOST]

Re: 1979 Mercury oil injected 150

Is it a V6, and what is your serial #?