Exhaust valve hit piston

[B3njammin89]

2010 Yamaha F115 four stroke exhaust valve hit piston. Has slight marks from the valve hitting the piston in the grooves that looks like that lines up with the valves. Will this affect my new valve when I install. I am not sure if the valves actually seat into those grooves when the piston comes up .

[robert graham]

Need to find the cause....timing belt jumped timing, bad wrist pin bearing?...did the motor stop running when this happened?....

[B3njammin89]

Need to find the cause....timing belt jumped timing, bad wrist pin bearing?...did the motor stop running when this happened?....

Motor did not stop running. Developed a knock sound so I turned motor off. Timing appears to be in sync according to manual

[99yam40]

as he said the cause needs to be found.
something caused that valve to not close when the piston came up.
if out of time I would think more that one piston/valve would show that damage


I take it the valve is bent , how does the valve stem look?
did it bind and seize due to carbon,or lack of oil(lubrication),
was the hit bad enough to possible do some damage to the piston or rod that could cause major problems later on?

[TownsendsFJR1300]

I take it it happened after the knocking with the fuel pump replacement?

http://www.yamahaoutboardparts.com/f...lr-motor-knock


Did the fuel pump knocking have anything to do with the valve and what was the knocking sound with the FUEL PUMP ISSUE?

Seems their likely both related...

The engine has 4 valves, 2 intake and 2 exhaust / each cylinder.. ( https://www.boats.net/catalog/yamaha...txr-0410/valve )

Just one valve got bent??? If so, as noted above, why? Valve retainer come off?



Re the piston, it's probably a relief cut out on the top of the piston. If the valve just touched, and took the brunt of the impact, the pistons likely ok.

I'd be checking play of the new valve with the valve guide(s) while it's apart and within spec.





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[99yam40]

I am sure the knocking he heard was from the valve and piston impact

[B3njammin89]

as he said the cause needs to be found.
something caused that valve to not close when the piston came up.
if out of time I would think more that one piston/valve would show that damage


I take it the valve is bent , how does the valve stem look?
did it bind and seize due to carbon,or lack of oil(lubrication),
was the hit bad enough to possible do some damage to the piston or rod that could cause major problems later on?

The valve to piston damage looked very minimal. You had to look real close to notice. I know any damages to the piston is is not good regardless. Yes the valve is bent in the head. I didn’t want to do more damage so I am taking it to machine shop Monday to have them check it out. All the other valves appear to be good. They all look seated in the closed position after I pulled head off.

[B3njammin89]

I take it it happened after the knocking with the fuel pump replacement?

http://www.yamahaoutboardparts.com/f...lr-motor-knock


Did the fuel pump knocking have anything to do with the valve and what was the knocking sound with the FUEL PUMP ISSUE?

Seems their likely both related...

The engine has 4 valves, 2 intake and 2 exhaust / each cylinder.. ( https://www.boats.net/catalog/yamaha...txr-0410/valve )

Just one valve got bent??? If so, as noted above, why? Valve retainer come off?



Re the piston, it's probably a relief cut out on the top of the piston. If the valve just touched, and took the brunt of the impact, the pistons likely ok.

I'd be checking play of the new valve with the valve guide(s) while it's apart and within spec.





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TownsendsFJR1300 Honestly I think I got the short end of the straw with this boat when I purchased it. It ran good til after starting it up with the new fuel pump. I’m thinking the valve to piston contact was the noise I was hearing from the low pressure pump with stethoscope. I didn’t feel any play in the pistons. The timing appeared to be in specs with the manual. I’m not sure if the original owner ever replaced the timing belt. Can a belt be stretched from age and alignment marks still line up?

[B3njammin89]

as he said the cause needs to be found.
something caused that valve to not close when the piston came up.
if out of time I would think more that one piston/valve would show that damage


I take it the valve is bent , how does the valve stem look?
did it bind and seize due to carbon,or lack of oil(lubrication),
was the hit bad enough to possible do some damage to the piston or rod that could cause major problems later on?

@99yam40 the small oil passage to cylinder 4 in the head looked clogged. I don’t know what it was but when I ran my finger over it a small piece of crud fell out and all of a sudden started pushing oil out of the hole. Could it be the lack of lubrication to the valve stem causing it to jam up?

[99yam40]

was it a drain hole that was plugged?
oil pressure would have pushed oil up into the head,but gravity drain back down to oil sump

[TownsendsFJR1300]

It's only one valve correct?

If so, if the timing was off both valves-adjacent (and likely others) would have been damaged...

Sludge found is obviously not good (and not really heard of in Yamaha OB's). Of course, no oil changes, proper service will cause it.. That seems to be the issue in your case.

The machine shop should be able to give you some insight into the oil passages and the reason for the failure while working on the head. If he can clean all passages would be good or yourself...

Sounds like the piston should be fine,

[B3njammin89]

was it a drain hole that was plugged?
oil pressure would have pushed oil up into the head,but gravity drain back down to oil sump

99yam40 the hole was very small like maybe a 1/16th if an inch.

[B3njammin89]

It's only one valve correct?

If so, if the timing was off both valves-adjacent (and likely others) would have been damaged...

Sludge found is obviously not good (and not really heard of in Yamaha OB's). Of course, no oil changes, proper service will cause it.. That seems to be the issue in your case.

The machine shop should be able to give you some insight into the oil passages and the reason for the failure while working on the head. If he can clean all passages would be good or yourself...

Sounds like the piston should be fine,

TownsendsFJR1300
Yes, just one valve visible to me. All the other valves look seated to me. Once I hear back from machine shop I will let you guys know what they say.

[zenoahphobic]

Sounds like a sticking valve. It didn't get back in time before the piston finally hit it causing more damage. (Note there is a difference in describing it this way, the valve did not open on the piston, as would be said if timing was out).
The simplest reason being lack of lubricantion or carbon build up.
You could have weak or broken valve springs, faulty collet system, or simply the valve guide has worn too much.

[TownsendsFJR1300]

99yam40 the hole was very small like maybe a 1/16th if an inch.

Too small for a drain, I'd bet that crap you found in the system caused no oil to the valve(stem/guide) and following failure-valve not closing / seizing up in the guide, then getting nailed..

Did you drain the oil yet and see if any clumps/crap comes out? Much if any sludge on the head (where the oil would be)?



*Now, IDK the answer but to prevent later failure, should that gunk be in the pan/oil system, how to clean the oil system W/O a full, engine break down??
Many oil changes, oil additives, ?





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