Why is there a break in required for Marine engines?

[NCFatBoy]

Are the machining tolerances for auto engines that much better than marine engines?

Break in on auto engines is really not that critical.

Is this just the result of high performance?

[falcooon]

My thoughts...

Automobiles and marine engines work in entirely different rpm, horse power, load and temperature ranges. Full power for hole shot, cruising on plane at 3000 and 4000 rpms, WOT runs at 6000 at various water temperatures for cooling...no coasting or down hill runs. Then, add the differences in lubrication systems of 2 stroke, and 4 stroke operation.

I think that all of these variables contribute to an effort to standardize the initial operation by the mfg for break in so we all start on the same page.

[NCFatBoy]

Yes. but even the four strokes have break in.

[microsalmo]

my thoughts:

all modern liquid cooled engines are built pretty damn tight but its give and take on how tight. i believe there are two things working against the SHO when it comes to this blow by issue.

the first being temperature - they designed this motor to run flat out and last! that means the internal parts wont expand enough to seal the bore until the motor sees alot of temperature. its during this heat up time that we get our blow by. its just like a race engine, in that tolerances wont be right unless you are running the snot out of it.

run it to easy or cold and the rings/pistons just wont get hot enough to fit tight enough to seal her up. the other way to build them is to run tighter tolerances with less load and less heat. problem with this is that when you do run it hard, things expand so much from heat that the oil cant get in where it needs to and boom. any engine builder will tell you its give and take and experimentation.

i think we are also dealing wih some very very hard metallurgy in the SHO that just takes time to seat. if you want it to last 1000 hours, it needs to be hard and will take some time to polish in.

once it does get run in though they seem to do well and quit with the blow by. i have had some lengthly discussions about this with yamaha customer care. they say the same stuff that we hear from our local dealers... break it in by the book.... then run it hard.... load it up good... get it hot.. ect. they know it takes some load to get those rings to cut in on that cross hatch.

...must be some hard metals they are using.

my .02 cents

[SkeetRJ]

Read the owners manual of your automobile.
When I bought my 2001 super duty, it had break in instructions in the owners manual. I assume it's the same for other automobiles also.
I think most people don't read the owners manual for cars and trucks, like they do for outboards.

[falcooon]

You are so right!

This is from my 2011 Tundra:

"Breaking in your new Toyota
To extend the life of the vehicle, the following precautions are recommended
to observe:
l For the first 200 miles (300 km):
Avoid sudden stops.
l For the first 500 miles (800 km):
Do not tow a trailer.
l For the first 1000 miles (1600 km):
• Do not drive at extremely high speeds.
• Avoid sudden acceleration.
• Do not drive continuously in the low gears.
• Do not drive at a constant speed for extended periods."

In spirit...not too different than a SHO or any other engine.

[Meleagris1]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by SkeetRJ &raquo;</td></tr><tr><td class="quote"> I think most people don't read the owners manual for cars and trucks, like they do for outboards.
</td></tr></table>

Exactly

[Altro Cat]

Every new engine has a break in procedure. My papaw is a diesel mechanic and even those things have break in, although they are usually done by the dealer before they are delivered to the customer. I have bought ATV's Side by Sides, and lawnmowers new and they all have break in periods also.

The last Stihl weedeater I bought even had a break in procedure.

[NCFatBoy]

I didn't say there was not a break in procedure, I said it wasn't critical.

If you're old enough, you'll remember when engine break in was important and if you had a good salesman, he'd tell you the break in, remind you of the break in as you left... Kinda like your boat dealer does for your outboard.

[NCFatBoy]

Thanks, good info....

[201pro]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by falcooon &raquo;</td></tr><tr><td class="quote">You are so right!

For the first 500 miles (800 km):
Do not tow a trailer.

• Do not drive at a constant speed for extended periods."

</td></tr></table>

When I picked up my truck from the dealer, I had my boat hooked up to my old truck and just swapped over and towed about 600 miles in the first 2 days of owning it. They knew what I was doing and never even said anything to me. Maybe that is why I am about 1 qt low at the oil change interval now.

[HAWKHPDI]

Yeah, I broke my '10 F 150 in just as much as you would any outboard. Motors are motors, I am a diesel mechanic and an in framed Cat, Cummins, or Detroit definitely runs better and lasts longer if we run it on the dyno under light load for a while.