Proper Break In Procedure

[jpuryear]

Hi guys,
The dealer is close to done with my boat (190 DCX), which included a rebuild on the motor. 1995 200 Mariner Magnum EFI. It ate the rings in 1 cylinder. My problem is the different stories I'm getting about how to break in the "new" powerhead. It has new rings and 1 new oversized piston. Mechanic's description is to "vary the RPMs for a while" ???? Service manual is alot more specific with max RPMs vs hrs on a schedule. There's also a disagreement on "double" oil. What are your thoughts on the right way to break in this engine on my 1st Champ?

Thanks!

[pmgoffjr]

Here's my *right* way...

Double oil...most certianly the first two full tanks.

The first twenty minutes is the whole key. It's pretty well done after that.

So...what I've learned is, you keep the motor trimmed all the way down, and for twenty minutes, it's hard on the gas, hard off, hard on...up to about 5 grand or so. After twenty minutes of this, I'll start to give it some trim, continuing the hard on/off scenario, until I have an hour on it. Then let it eat for short runs, less than ten minutes at a time, until you've got two hours, and then that's it, you're done.

The newer motors won't let you do that, the computer is under "break in" for eight full run time hours, but the hard acceleration when new is what firmly sets the rings, and that motor will live much longer than those that are babyied the first hour.

I ran into the guy who bought my '87 the other day, still using it frequently, still runs like a top. Never turned a wrench on the powerhead.

I was taught this by some master motor builders long ago, and have yet to see any reason to change my thinking.

[jpuryear]

Pat,
Thanks a million. I was hoping to get your reply. Also hope I get to meet you some day

jeff

[JohnM]

actually the book for a new Opti is not far off from what Pat describes. I had Sherm take me out the first trip with my new Merc. Idle only long enough to warm up, full trim down get on plane and vary throttle. I was varying 600 RPM's or so, he advised same as Pat. Wot full trim down on my boat before messing with Jp was 4500 RPM's and he would vary from just on plane to there. It took right at 3 hours to get my ECM out of "breakin" mode

Gotta run wife busted me laying in bed playing on BBC on my phone while we have company.