Anybody ever seen anything like this?

Are those areas burned?

Remove the valve and look at the seat.

It looks like little pieces were breaking off, not burning. I'll be tearing the heads down later this week and updating with seat pics if I find anything.

Try to see who makes that valve, I have seen pitting on valves from water on mostly the stem side, thats really strange! Looks like the valve rotates to one spot then begins to remove material, I take it the engine would back-fire through the intake.

As far as I know, the valves are factory but I'll check today. The engine actually ran fine with no backfire. I'm tearing it down due to a bit of oil consumption and found this by surprise.

Are you the original owner of the boat?

Are all the valves this way, or just a few?


There is a lot on info out there that would help, like what kind of engine is this? How, old, how many hours, salt/fresh water?

It might be just me also, but it looks a little lean hot in that chamber also. Are these factory engines?

What I find unusual with this, is that the intake valve appears to have gotten hot, not the exhaust??? Weird.

It is only one valve that has done this. The engine is a 9.0:1 454 with fact rectangles (088's). The valve are original from merc and have approx 100 hours on a valve job. I don't know the total number of hours. The cam is stock with 1.8 rockers and the exhaust is stock as well. It is used in fresh water only. The engine was tuned with a LM-1 and ran approx 12.5:1 at wot.