Powerhead break-in

[kengriff]

I just replaced the power-head on my 1987 Yamaha, 3 Cylinder, 50hp. I running a 25:1 mix with the oil injection as recommend by the SELOC manual. I gone through the tuning and timing/synchronizing procedures but still doesn’t idle smooth; is the because of the new power-head being tight and the heavy oil mixture? Also the manual doesn’t say if the breaking run should be in a test tank or with the boat in the water. I only have a 45 min. on it so far, just long enough to make sure it run and to synchronize every thing out.

 

[Jack Shellac]

Re: Powerhead break-in

The break-in procedure should be the same as for a new engine: 10 min at idle, 0ne hour at about half speed changing speed every 15 minutes, one hour at 3/4 throttle with full power for 1-2 minutes at intervals changing speeds every 15 minutes. For hours 3-10, avoid continuous full throttle for extended periods and continue to change speeds every 15 minutes. After it's run in for a couple of hours, readjust your idle with the engine in gear and under load. All of this is with the boat in the water, of course.

 

[Dhadley]

Re: Powerhead break-in

Why did you have to rebuild it?<br /><br />Did you clean the carbs?<br /><br />Good luck!