What would cause piston to look like this????

[Bassfishing1221]

I have a 2001 Yamaha vmax 225 and yesterday I was running wide open and it started bogging and shut off. Went to restart and engine was locked up. What causes to piston to look like this. Only two pistons are bad( center piston on both sides)

 

[Scott Danforth]

Detonation from running lean

Fix your fuel system

 

[racerone]

Oil injection issues.----Wrong prop for the boat.------Wrong timing.------Overheating.-----High RPM / over the maximum range.----Partially plugged carburetor.

 

[Bassfishing1221]

I was leaning toward faulty oil pump but wasn’t sure if it would just effect the two middle cylinders. Is there away to test oil pump

 

[jerryjerry05]

There shouldn't be a carb on a 01 225.
You should always include the model, serial# off the little stickers on the motor.

Water, sludge in the oil tank, bad oil pump, clogged injector?

 

[Scott Danforth]

I was leaning toward faulty oil pump but wasn’t sure if it would just effect the two middle cylinders. Is there away to test oil pump

oil pump would affect all the pistons.

only fuel system would affect a single piston.

 

[Bassfishing1221]

Is there a way to test oil pump?

 

[Bassfishing1221]

And what’s the odds that two injectors went out.. especially both middle injectors. I’m sure the other pistons are burnt a little but they aren’t crumbling to pieces like the two centers are. I figured middle to are worse because they are the hottest cylinders

 

[racerone]

Scott.----Oil is NOT mixed with the gas on this motor.----Oil is injected after the carburetor at the intake manifold.----Six hoses come off the pump.

 

[Scott Danforth]

I wasnt even looking at oiling. the piston looks like it was running about 25:1 on the air/fuel ratio - extremely lean, causing extreme high temp and detonation damage.

 

[racerone]

If 2 oil hoses were damaged / pinched / disconnected it would affect 2 pistons