Braking in a new motor

[Doug H.]

What do most of you guys do on braking in a NEW jet boat motor.
1. put in engine and run a water hose to it for 20minutes at 2000rpm's while on trailer ?....
2. put boat in lake and idle at 2000rpm's for 20minutes ?
or is there another way that im missing ? give me your pro and cons or do's and dont's .......................thanks, Doug.

[Tom Brown]

A stern drive?

[Cas]

I've always broke them in on the trailer in front of my house to make the neighbors happy.

[Doug H.]

Tom didn't you read the above caption ? (jet boat) hellooo.

[Rexone]

It doesn't matter where. Just make sure you don't idle it for the break in period. I always stretch the time a bit too just to make sure. Seen too many flat cams.

[JetBoatRich]

New Motor Doug:mad: what did I miss:confused:
Vary the RPM's for sure, with the new pump to go with it:eek: you may want to hit the lake and just cruise around.

[Tom Brown]

Originally posted by Doug H.
Tom didn't you read the above caption ? (jet boat) hellooo.
I guess not, sorry. In that case, I'd go with a good quality mineral oil based TC-W3 oil for the first 20 hours before switching to synthetic. Don't forget to double oil during breakin too.

[78Eliminator]

Assumptions, assumptions. Is it a flat or roller valve train? What kind of rings? Were the bores finish honed?
Depending on the machine work and parts used, there might be ZERO break in time. Regardless, be sure and change the oil after the first run on the lake.

[Doug H.]

The cam is hyd. and everything is new.
I was wondering which way is best to do my 20 minute run in at 2000 rpm's.
on the water ?
or on the trailer ?

[BADBLOWN572]

I was always told that the boat needs to run at various RPM during the break in period. Don't want to run any distance at one RPM. When we had out jetboat, the builder said that the best thing to do was to go water skiing. A lot of various RPM's.

[Hal]

You need the 2000 rpm and above for the frist 20 mins to break in the valve train. If you can't uncouple your pump I would put the boat in the water for the break in.

[Doug H.]

Thanks guys for the info.............any more ?

[Drunk tank]

Originally posted by Doug H.
The cam is hyd. and everything is new.
I was wondering which way is best to do my 20 minute run in at 2000 rpm's.
on the water ?
or on the trailer ?
I'd say on the trailer... that way if ya kill it you arnt sittin in the middle of a lake like a jackass (I am often in that position... though my engine is well broken in):D

[CrazyHippy]

Flat out, just like the NHRA guys do, and they make loads of power.
BJH:rolleyes:

[JetBoatRich]

Originally posted by Doug H.
Thanks guys for the info.............any more ?
Doug what is your plan, B.V. in the schedule real soon?

[Jetdriver]

Hey Doug just disconnect your pump then run it on the trailer!

[Danhercules]

Originally posted by Jetdriver
Hey Doug just disconnect your pump then run it on the trailer!
Thats what I just got done doin.

[Dr. Eagle]

My understanding of what it takes to break in a new motor is that as others have said, you vary the throttle settings constantly. When you first start it up you should not exceed a fairly low rpm level (say half throttle or so) for the first hour or so. Then progressively more throttle can be given.
But the other thing I have been told is that it is best to do it under load. You can't simulate that w/o hooking up a dyno...:D