Yamaha 250 Block Corrosion

[fordfisherman]

Looking at a boat with twin 05 250s. One midsection was replaced and some corrosion was noted on the powerhead. What’s the expected life of the motor moving forward?

 

[Billv]

Not intending to be funny but short. Once the corrosion starts the engine will fail eventually. I learned the hard way

 

[fordfisherman]

Looking for anyone who’s been thru this and an estimated timeframe to expect failure. Has anyone welded the powerhead with success?

 

[seasick]

The funny thing is that one motor can have corrosion but the other has none. I mention that because you didn't specifically mention the other motor.

It is hard to sat what life is left without knowing the extent of the corrosion and the corrosion if any in the second engine.
If the lower oil pan has corrosion, failure mode is near and often catastrophic. What tools or procedures were used to inspect the motors?
Personally I would pass on the boat unless it was priced like it had no engines, Even then, a repower may be not in your budget.

 

[DennisG01]

Looking at a boat with twin 05 250s. One midsection was replaced and some corrosion was noted on the powerhead. What’s the expected life of the motor moving forward?

There's really no way to give an accurate estimate. But we can at least offer better ideas if you provide much more detail and multiple pictures about what "some corrosion" means. Plus, the way you make it sound, it seems like the corrosion is on the outside of the powerhead... so... clean it off

 

[Ekea]

like dennis said, you need to provide more info for anyone to be able to provide a guess.

 

[fordfisherman]

The exhaust was replaced and there was corrosion on the block near the mating surface. Only have a pic of the upper leg: