Engine Break-In

[kaydano]

I'm pretty sure engine break in has been discussed here a few times, but I searched and didn't find it, plus if I recall, the question on how aggressive you should be wasn't answered....

For example, according to Mercury, for the first X hours you are supposed to vary the engine RPMs but don't exceed XXXX rpms. So, the question is, should you slowly work the throttle up and down that rpm range, or should you do it aggressively (as in flooring it, then stopping when it hits the high end of the range and back off quickly back down to idle)?

Thanks!

 

[cwag911]

No slamming the throttle until the break-in period is over. But don't be a wuss with it either. B)

 

[Ecoman]

I drove it like stole it. It didn't hurt anything for me. Engines are made pretty good today and I believe they can take it but if your manual said not to then do what it says.

 

[mtudb24]

Dano. I did the break on on all my outboards slow and steady. I've never had a problem, but as stated, today's outboards are rock solid and somewhat bullet proof.

 

[Bamaman]

Sorry guys, but I disagree about durability of all modern outboards. Yamaha is having terrible troubles with their new generation SHO motors "making oil". They've had too many engines blow up (especially on bass boats), and the Yamaha's replaced powerheads right and left.

Unfortunately, Yamaha has understated the problems to customers and the dealers are simply keeping their mouths shut. Many SHO's are just coming out of their initial 3 year warranty period, and customers are trading out of them. A used SHO engine might be a good one to avoid on the used market unless it comes with a good, long factory backed warranty.

The problem is that gasoline is bypassing the rings and going into the oil sump--thus the raising of oil levels. The rings never seated properly in the bore during their rather lengthy initial break in period. The SHO engines run very, very cool, and higher engine temperatures might better seat the rings better during break in.

Yamaha's cure is to change the oil anytime an engine's "making oil," warm the engine up carefully and run the hell out of the engine. Many engines that previously "made oil" have quit doing it. But many engines have continued to "make oil."

It's unclear if the more recent SHO engines have lower incidences of problems But I understand that any 4 stroke engine has a chance of this happening to it. I bought a F150 Yamaha that's been around 7 years, and they seem to be more durable.

But when SHO's run right, they're very popular with fishermen and even owners with problems continue to trade for another SHO. Many customers intend to trade again before they engines are out of warranty.

The jury is still out on these engines. Since Yamaha has been so close mouthed about their SHO powerhead problems, it's not clear if they've solved their problems.

Bennington is the largest buyer of Yamaha engines and many toons have SHO's on them. Everyone really needs to know about the problems, and they can read on other places on the internet about SHO's. BBCBoards.net is a huge bass boat website, and it has a forum section on Yamaha engines with this problem discussed in detail.