Yanmar 3GM Break-In Procedure ?

[riptide]

Hi all - just finished rebuild on my Yanmar 3gm.New pistons,rings,liners,main and rod bearings.Anyone know recommened oil and break-in procedure?Thanks

[GordMay]

Until our mechanics chime in:

Yanmar Break-In Procedure:

Prolonged idling of diesel engines is not good for them.

For the first 30 minutes, maintain idle to about 1500 RPM, until the engine temperature has stabilized, then advance to Maximum Loaded RPM, in 200 RPM increments, over about 15 -20 minutes.

If the engine can't reach its correct maximum RPM then slow down, return to the dock, and have it fixed or explained*.

For the next 5 hours running don't operate the engine at more than 85% RPM (nor less than 2000 RPM) and every 20 minutes change the RPM up or down by 200 RPM. When the 5 hours are up, you’re good to go cruising.

* I’ve never been able to take a sailboat’s diesel auxiliary to Max Rated RPM.

[Solitude]

Change the oil and filter after 50 hrs.

[never monday]

run the we-we out of it.

Tie off good in the slip.
Initial start, hold the compression release open and turn it over a few time to get oil pressure.
Drop the lever and let'er rip. engage forward or reverse. Depending on what way your pointed in the slip. Run the RPM's up to the point of smoke production and back off until it goes away or 3400 whichever occurs first. Let it run for a few(2-3) min, honest min with a clock. Then start varying the rpm's all over from 1200 to 3600 in 5 min intervals, for the first 30 min.

[motion30]

Originally Posted by never monday

run the we-we out of it.

Tie off good in the slip.
Initial start, hold the compression release open and turn it over a few time to get oil pressure.
Drop the lever and let'er rip. engage forward or reverse. Depending on what way your pointed in the slip. Run the RPM's up to the point of smoke production and back off until it goes away or 3400 whichever occurs first. Let it run for a few(2-3) min, honest min with a clock. Then start varying the rpm's all over from 1200 to 3600 in 5 min intervals, for the first 30 min.

yea do that

[riptide]

Thanks for the replies. It seems the major thing is to vary the rpm,s so that's what I'll do thanks again.