What do you think wrench

[aarchdale@coresleep.com]

Buddy had his 95 EFI quit on him. I took a couple pics. Only this one piston and cylinder looks beat up all the others look fine.  It was the bottom hole starboard side. Maybe a reed broke?  

[fishinwrench]

Detonation on the exhaust port side of the cylinder indicates a combustion chamber overheat.   And the "coking" (heavy carbon deposit buildup) on the piston above it indicates over-oiling (probably from an oil injection pump not being synced properly.....or too much oil being added to the fuel IF the O/I had been deleted). 

Too much oil can cause an overheat, as excess oil slows the burn....which equals more time that FIRE is in the cylinder.   

You can tell that it has been going on for awhile......It just didn't completely loose power until the piston rig broke into pieces. 

 

If it was a typical overheat (like from a bad water pump)  then the detonated piston would be gray and dry looking.... but you can clearly see the wet & black deposits of over-oiling even on the damaged piston.   

When that powerhead is disassembled there will likely be baked-on (black) deposits ("coking") on the UNDERSIDE of those pistons as well.   And that confirms 100% that too much oil has been injected into the crankcase......Either from improper sync of the injection pump, or a oil injection pump that has failed and just fed oil unmetered, by gravity.    

[fishinwrench]

Here is what a typical overheat detonation looks like.   Notice how dry & gray the piston is?  And piston damage mostly confined to the exhaust port area.

[aarchdale@coresleep.com]

He wont admit it but i think it had been down on power for a while, Last time i was with him it wouldnt get on plane unless i sat on the front deck which didnt used to be the case. It still has the oiling system in it for sure.  He has found a used 98' EFI that has everything on it he is getting this weekend, hopfully that powerhead will bolt on to his 95 mid section

[fishinwrench]

5 minutes ago, aarchdale@coresleep.com said:

He wont admit it but i think it had been down on power for a while, Last time i was with him it wouldnt get on plane unless i sat on the front deck which didnt used to be the case. It still has the oiling system in it for sure.  He has found a used 98' EFI that has everything on it he is getting this weekend, hopfully that powerhead will bolt on to his 95 mid section

Just be sure to realize that REPLACING THE POWERHEAD is not FIXING the problem.  He's gonna just blow another one if the over-oiling issue isn't rectified.   👍

Good luck. 

[aarchdale@coresleep.com]

1 minute ago, fishinwrench said:

Just be sure to realize that REPLACING THE POWERHEAD is not FIXING the problem.  He's gonna just blow another one if the over-oiling issue isn't rectified.   👍

Good luck. 

That what I told him.  Apparently the powerhead he is complete with everything still on it.  It was an insurance claim that the guy hit somthing and ruined a lower and mid section so the whole engine was replaced and it has just been sitting at some marine place in Monett for years.

[fishinwrench]

[aarchdale@coresleep.com]

Hopefully it is what the guy says and it comes with all the electrical and all the components and he only has to put the new one on his mid section and get rid of everything else from the blown one

[fishinwrench]

3 minutes ago, aarchdale@coresleep.com said:

Hopefully it is what the guy says and it comes with all the electrical and all the components and he only has to put the new one on his mid section and get rid of everything else from the blown one

Fat chance....but ok. 😅

[dblades]

I have faith in Bill's grandson.