Omc 115 Turbojet Doesn't Cranck

[Thunderwave]

Hi all , I have an OMC 115 Turbojet out of 1994 , after driving the boat for 10 min. the rpm came not above 4000rpm , cause , 1 spark had a malfunction on the lower cilinder left side. After changing this with new sparks he run at 5000 rpm and plane but after 10 min,. he automatically drops the rpm to 2000 and after taht he stops. after restarting te engine , he run with a very vibration and a havy sound. We went up tu run the boat and he runs again 5000 rpm , but not the max reaching rpm of 5800. after 3 minutes the bout rpm going down untill he stopped , after restarting he would cranck anymore untill he cooled down for 5 minutes . than he starts wih a heavy noice and stops and will not crancking before colling down.
What could be the damage , Any suggestions ???

 

[tashasdaddy]

Re: Omc 115 Turbojet Doesn't Cranck

sounds like it's running hot. and ceasing. other word sound like you burnt it up.

 

[ezeke]

Re: Omc 115 Turbojet Doesn't Cranck

Tashadaddy is rght. Do that a few more times and you will have some not-too-valuable scrap metal.

You are not getting water through the cooling system. You will need a service manual to work on the motor. Except for the Boston Whaler and Four Winns, there are not that many of the OMC 115 inboard crossflows around, and this forum is mostly for outboards.