Warm up/breakin

[getfished]

OK I'm waiting on a new 250 Pro XS 4 stroke. I'm sure I'll get some instructions from the installing dealer along with an owner's manual. Here's my situation that I don't understand. In an earlier thread I believe it was reccommended to run the motor through 2 temp cycles in the first 2 hours. Does this mean bring the temp up to 120 like we do with a two stroke , cooling down and then repeat, or bring up the temp to the point the thermostats cycle , cool down and repeat ? If either of these is the suggestion IMO that can be done at the ramp without ever launching from the trailer. Methinks there is more to it . Is there ?

Second thing I would like to understand better is the breakin process itself. I won't be deviating from the proper method but why does a V8 4 stroke outboard require a breakin period and specific process where as a new automobile with say a V8 4.6 motor does not ? What is the difference ? I realize the rpm range is quite different and somehow I think that is a clue but I don't understand the rest of the story for breakin.

[5keepers2]

Here is my take. The new marine 4 strokes run cooler than autos. You need to load them and get them up to temperature to set rings. A couple of max heat to cool cycles are good. Suggest you leave trim all the way down/in and plow your way around lake for a couple of hours constanly varying rpm's and not going above 4500.. Go to full throttle (trim down) for a minute or so twice during the 2 hours. Think of it as working hard!

[EuropeanAM]

Up to temp, Up on Plane, go run following break-in instructions, return to idle, shut down, and allow engine to return to ambient air temperature.

That is a heat cycle.

[deepweer]

The manual doesn’t say anything about the heat cycle but it seems like something that could potentially help and should not hurt, so I did it. The manual describes running at WOT for short periods, but doesn’t say anything about load or RPMs. I ran mine around neutral trim and got into 5k range, and hope this worked. Have not had enough time to tell.

[OldTimer57]

Have not run a new v8 for break-in myself, but the 2-strokes would tell you if you were making progress on break-in if you had smart craft instruments. If the motor wasn't properly loaded, you would just be running around burning double oil and making no progress on the break-in count down... I had a friend a few years ago that bought a new boat, took it out for several weekends running it around. Went with him down to the river to help him address chine walking and discovered the count-down timer was still almost at two hours. Asked him about running it loaded and he said he had carried an extra 25 pounds of something. Explained that was not exactly what the manual meant. :)

Did tell him that if he finds a bottle of something that says "shake well" that it means "shake the BOTTLE." :)

[mikesxpress]

Don't get drug into the weeds on this with heat cycles. Just follow the break-in instructions Mercury has in the manual.

[EuropeanAM]

Don't get drug into the weeds on this with heat cycles. Just follow the break-in instructions Mercury has in the manual.

[12many]

don can break in be accomplished adequately just after ice out in 37 deg water? I will be breaking in my new v8 soon as rivers open up.
I will have vessel view mobile? any thoughts on this

[EuropeanAM]

In theory, it could be accomplished under those circumstances. Personally... I would prefer warmer, but I'm very certain that is not even close to the "coldest" they've been run (new).

[dawg08]

Up to temp, Up on Plane, go run following break-in instructions, return to idle, shut down, and allow engine to return to ambient air temperature.

That is a heat cycle.

What in your opinion and experience would be a good estimated time frame for the engine to return to ambient temp after shutting down?

[getfished]

That would probably be dependant on the air temp. My guess is minimum 1 hour maybe 2 to be sure.

[dawg08]

Yeah, my thinking was a 60 degree or cooler day it would cool to ambient temp much sooner than a 70 degree or above day. I was thinking a 1-1/2 to 2 hour period would cover either or myself. Just looking for an experts opinion.

[BCLII]

I think your right in the time frame. Coming from the frozen tundra, it’s going to be weighed on the air and water temperature!

[getfished]

Hopefully you will a comment from an expert. It certailnly isn't me. LOL

[Triton19x2]

Of course I would think the two heat cycles don't have to be on the same day but as long as they are in the first 2 hours.....

[dawg08]

Hopefully you will a comment from an expert. It certailnly isn't me. LOL

Not that I don’t trust your info. I haven’t really had a reason to post on BBC in quite some time. I just know by reading a lot lately Don is a multi service award winner and is a master tech. Not sure about anyone else.

[EuropeanAM]

Yeah, my thinking was a 60 degree or cooler day it would cool to ambient temp much sooner than a 70 degree or above day. I was thinking a 1-1/2 to 2 hour period would cover either or myself. Just looking for an experts opinion.

Normally about right. Going to vary based on air/water temps on the particular day in question.