Break-in for new motor

[walleyewizard]

I just bought a new Yamaha 150 4-stroke. The dealer recommended going through 2 tanks of gas at varied speeds before I run it at full speed. The owners manual says that by the end of 10 hours of varied speeds it should be ready to go. I figure that with the good fuel economy of this motor, if I have to go through 2 full tanks of gas, I may not have it broke-in for 2 years!! Any opinions out there?

[196thDLR]

WW: In 2003 I bought a new 75HP, 4-stroke Yamaha. I purchased it in July of 2003 and did not have 10 hours on the motor until June of 2004! I made sure that I had the required amount of hours on the motor before I opened it to full throttle. I think that time was 4 hours. My manuel is out in the boat, and it is raining here and I have a detached garage. Good Luck.

[Fish02Tour]

I broke in a new Yamaha F115 2 years ago, did it by the manual which was what the dealer said to do. Depending on the size of your tank I'm not sure how many gallons it will take, just follow the manual. Ten hours is a lot of running but you can do it in a day or two.

Great motors!

[MLaker2]

I bought new 150 Yam 4 stroke last fall. Dealer sells lots of bigger boat/motor rigs. He highlighted the section in the manual. One hour at 2000 rpm, 1 hr at 3000 rpm, then only short periods at wot. Tilt motor all the way down so it has to work some. You want your motor to get warm enoough to seat the rings. Spend a good 2 1/2 - 3 hrs in your boat getting your first break-in period done right. There has been a history with Yam powerheads adding gas to the oil if rings not seated properly.

My .02.

[kjgmh]

On a 4 stroke make sure motor is warm and run it like you stole it. I have been told this by tech reps from both Yamaha and Mercury. If you blow a powerhead on a Mercury(Yamaha) 4 stroke Mercury will pay the dealer to run the snot out of the new powerhead for 2 hours to help the break in.

[waskawood]

Does anyone know why Evinrude is saying no break in required on the new E-techs?

[gilby]

There might be more to it than this, but, I think most of is due to the oversized internal engine parts.

[Leader]

it's mainly so the piston rings seat(conform to shape of cylinders)throughout the complete RPM range. after an hour of constant throttle varying you can spool it up to wide open for a very short distance to seat rings at wide open also or it may be a pooch. that hour of varying the throttle will take the sharp edges off the rings and they wont snag on the fresh crosshatching from the final cylinder honing.

just a case of manufacturers covering their hinders from facory defects, if something goes wrong at WFO(wide frickin open)the results tends to be very ugly inside the motor, but if it happens at lower RPM'S they can get by with fewer parts to replace or repair.

although to be "safe". after running at varing throttle positions for 1 hour, shut down motor and let it completely cool down, then restart varying throttle for 10 minutes more before the short burst of WFO so the piston also conforms to the shape of the cylinders. then you'll get the most potential out of the motor you can at this time.

after running it for 10-15 hours you will gain another 1-3 hp from everything loosening up.

Good luck with the new mill.

[united jigsticker]

So....

I have about 13-15 hours on my 2004 yamaha 2 stroke...

I imagine the same principles apply for seating the rings.

In the total estimated engine run time I have on my motor, I'll take a ventures guess that it has been at wide open throttle for a total of 3 minutes.

I rarely go over 3/4 throttle..

Why?

I'm paranoid.

I blew one up at WOT 4th of July weekend a few years ago. That whiny slow dog sound and then the ensuing "tink" that followed, and the awful feeling of trying to free it up via turning the flywheel by hand....

Well lets say I can still hear that sad "motor freezing up" sound in my head, and somehow my brains manufactures the sound anytime I have my motor running in the upper RPM range.

The motor I blew up was a 96' 50 HP Johnson...3 cylinder.

They made them in both a twin and a triple. We opted for the triple.

After I blow the motor up, the dealer tells me it is very common...For the center cylinder to go on these engines.

We tear this bad boy down...and the center cylinder is toast!

Man. If they knew about this issue being so common, you'd think maybe a recall, or some kind of reimbursment or something would be in my favor...But nothing of the sort.

So I bought a 50HP 2 stroke Yamaha to replace it. Ran that thing hard after the intial 3 hours. And it ran great!

Now I have a 70hp 2 stroke on my new boat...and I baby the thing...And I don't baby anything.

I run everything like I stole it...Except this motor.

3 minutes of WOT in 13-15 hours of operation.

Sad!

I have a 2005 Silverado with 900 miles on it. Yesterday as I was returning from my outing, I was doing 90 mph pulling the boat in 3rd gear down I-35. What do ya' think of that?

I drove it today, and it seems to have a bit more "pep" to it. Maybe I did it some good by "gettin er' done!"

Do ya think with 13 hours and change on my outboard, I should take her out and open her up for a good 3-4 minutes at a time with a 3/4 throttle break for cooldown?

Thats what the manual says to do 5 hours of operation ago.

Have I done it?

No.

Will I?

Maybe.

Why haven't I?

I'm scared.

[walleyewizard]

Mission accomplished. Spent 3 1/2 hours on the Mighty Miss. Man, is that a sweet motor! Just wondering what other guys get for top-end and bottom-end with their 150's?