Corrosion problems in cylinderwalls with Yamaha F300 2017- common?

[Hasse_231]

Hi there

I have a question for you guys. Im looking to buy a boat with Yamahas F300 2017-. And due to bigger issues since before i bought an inspection camera (teslong) to verify the condition on every engine im intrested in.
So i have checked 3 engines who do have between 100-200 hours on them and service is made by authorized workshops. All of them have corrosion on the cylinder walls, some more some less. But are those engines only wrongly winter preserved with no oil in the cylinders or do Yamaha have a corrosion issue with those engines?

Im not intrested in any of those engines at all but am i wrong? Is this normal? Pictures from 2 engines. Do i need to buy a new boat? I usally keeps my boat round about 7-8 years, so i dont want to rebuild an engine that have a few hours on it?

Kind regards Hasse

[robert graham]

Maybe motors stored near salt water….maybe motors not fogged with oil before lay-up…..that said, the corrosion in the photos don’t look like they would effect compression much if any…

[panasonic]

Age old problem with Outboard motors...not used enough. Sitting around for long periods of time in between using them. If I were interested in buying one of those engines I would run it and bore scope it again. If there was no noticable pitting on the cylinder walls then I would consider buying it.

I done my fair share of borescoping jet engines and other hard to see areas on the aircraft. When you first do it and find something that makes you go... that's not good. Then you take it apart and find out it isn't what it seems to be. The scope generally makes things look worse then they really are because the lens is really close to and focuses in on the defects. We are using $50,000 scopes and they can fool you. It takes a while to get used too doing.

If you had the head off that engine and seen that rust it may be just a few swipes with a bit of scotch brite on it would be gone..or maybe not.

I am going to assume that these engines have cast iron cylinder sleeves.You can almost watch cast iron rust when it becomes dry of oil. A good example of this is the cast iron rotors on your car, they can develop surface rust overnight or over several days. You drive the car and on the first application of the brakes it sounds terrible but the rust is gone. No harm done.

Good on you for taking the time and effort to look as 99% of buyers would not.

[boscoe99]

Yamaha 4.2 liter models have flame sprayed cylinder wall liners. I suspect that is what the OP is seeing.

[panasonic]

Yamaha 4.2 liter models have flame sprayed cylinder wall liners. I suspect that is what the OP is seeing.

See...that's what I get for assuming.

[panasonic]

Yamaha 4.2 liter models have flame sprayed cylinder wall liners. I suspect that is what the OP is seeing.

Any idea what material is being used?

I remember back in the 80's many snowmobile manufacturers got rid of cylinder liners all together. The aluminum bores were coated with a hard layer of "chromal"or something like that. Worked very well but no repair for damaged cylinders as coatings were very thin. If you scored a bore then the cylinder was junk.

[boscoe99]

Any idea what material is being used?

I remember back in the 80's many snowmobile manufacturers got rid of cylinder liners all together. The aluminum bores were coated with a hard layer of "chromal"or something like that. Worked very well but no repair for damaged cylinders as coatings were very thin. If you scored a bore then the cylinder was junk.

Don't know what the material is.

I have read on the innerweb about shops that can strip and respray the liners. Not sure if they know exactly what Yamaha uses or if they just use what they know that works.

Cracks me up when some call it plasma spray. As if plasma is the material being sprayed. Some folks at Yamaha called it plasma peel if and when the liner got scrubbed off.

https://autocraftsg.com/solutions/en...mbly/ptwa-rsw/