Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

[eddy2419]

2003 250HPDI, blew #2 cylinder at 503 hours. The price when I bought the boat was low enough to justify another PH in the future, and more. My yard got a rebuilt PH from large well respected company that only sells to dealers. All the oiling upgrades were done before I bought it. I went over board on the break in of the PH.

At 580 hours, clank, clank. Cylinder #5 had 0 PSI and 6 had 35#'s. PH removed and sent to the rebuilder, who I spoke to on the phone. Not covered under warranty as the #5 piston has a hole in the top, indicating, they said, an ignition/timing problem. The #6 issue was debris from #5 getting into it before it all exhausted. They were very helpful and are repairing the PH and shipping it back to the yard for $750. The repair place that put the first one is no longer in business so I am dealing with another yard this time.

My utmost concern at this point is that the issue does not repeat with the new PH. What would cause the burnt piston and what do I need to do to fix it?

Also can you premix oil during break in without clogging the injectors? During last break in the oiler was increased and oil was squirted into each intake every 1 - 2 minutes for the rebuilder. No premix and I left the oiler as it was, never cut it back.

Thanks in advance.

 

[eddy2419]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

bump

 

[eddy2419]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

Bump. Help! Before I blow the new one!

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

my father have a marine workshop and i have learned from him since i was 7 years old now im 18 but im pretty good at this im from mexico and we have repaired 6 vmax 225-300 hpdi 3 for the same problem u have, we?ve changed the oil sistem for a new one i mean the pump and valves and we reccomend to use the lowest octane gasoline
these motors were repaired like 2 1/2 years ago and they are like new

now i am repairing a 300hp vmax but i lost the torque specs of the engine
can u help me plz??

juan carlos

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

ahh btw this model of yamaha have trouble in piston #3 almost all the time when that happens that piston is the first affected
but if u take in mind what i said and u be careful with ur engine it will work for more time.

 

[Faztbullet]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

Injectors should always be cleaned flowed and balanced on a reman powerhead. Sounds like you have injector issues and there are issues with mechanical low pressure pumps leaking into crankcase and washs lube off cylinder causing failures..

 

[boscoe99]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

my father have a marine workshop and i have learned from him since i was 7 years old now im 18 but im pretty good at this im from mexico and we have repaired 6 vmax 225-300 hpdi 3 for the same problem u have, we?ve changed the oil sistem for a new one i mean the pump and valves and we reccomend to use the lowest octane gasoline
these motors were repaired like 2 1/2 years ago and they are like new

now i am repairing a 300hp vmax but i lost the torque specs of the engine
can u help me plz??

juan carlos

Are you sure you are using gasoline with the lowest octane rating?

Did any of your pistons look like this one (from the number two hole of course)?

 

[boscoe99]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

ahh btw this model of yamaha have trouble in piston #3 almost all the time when that happens that piston is the first affected
but if u take in mind what i said and u be careful with ur engine it will work for more time.

Here in the US it is usually the number two piston that goes first.

 

[boscoe99]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

Injectors should always be cleaned flowed and balanced on a reman powerhead. Sounds like you have injector issues and there are issues with mechanical low pressure pumps leaking into crankcase and washs lube off cylinder causing failures..

The engine rebuilder told the OP the damage observed was more than likely ignition/timing related. I see much, much more detonation damage in HPDI's than oil related failures.

But you are absolutely correct about the need to inspect the fuel system before dressing a new block with the used accessories.

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

The engine rebuilder told the OP the damage observed was more than likely ignition/timing related. I see much, much more detonation damage in HPDI's than oil related failures.

But you are absolutely correct about the need to inspect the fuel system before dressing a new block with the used accessories.

yep you are right i was confused actually goes #2 first and then #3 and #2 looks exactly the same and its the most affected

i repaired the engine and i told the owner to premix oil so it will have more lubrication in pistons and it will prevent that again

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

also does someone know what happens with the transmision oil??
first you filll it, then you use your boat normally after 5 or 6 times you use your boat there are like 100-300 ml missing
well at least is what happens here in mexico
pd. the transmision is totally sealed and i send it to check to factory, they send a new one and happens the same.

 

[boscoe99]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

yep you are right i was confused actually goes #2 first and then #3 and #2 looks exactly the same and its the most affected

i repaired the engine and i told the owner to premix oil so it will have more lubrication in pistons and it will prevent that again

Uhhh, with an HPDI you can't run premix. The gasoline is injected directly into the combustion chamber and bypasses all of the parts of the motor that need to be oiled. Oil has to go to the motor via the oil pump.

 

[boscoe99]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

also does someone know what happens with the transmision oil??
first you filll it, then you use your boat normally after 5 or 6 times you use your boat there are like 100-300 ml missing
well at least is what happens here in mexico
pd. the transmision is totally sealed and i send it to check to factory, they send a new one and happens the same.

It is recommended that a gear case be filled slowly until bubble free oil comes out the vent hole. Then take a five minute break. Come back and slowly top off the gear case. Then reinstall the vent plug. As quickly as possible reinstall the fill plug.

Gear oil is relatively thick. It can take some time for oil to make its way into a number of cracks and crevices inside the gear case. If someone pumps oil into a gear case quickly and stops at the first sign of oil coming from the vent hole, it can be under filled.

 

[99yam40]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

i repaired the engine and i told the owner to premix oil so it will have more lubrication in pistons and it will prevent that again

My thoughts are lack of oil will usually get bearings 1st, so premixing will not solve that piston failure
lean on fuel or overheat will get piston like that
lean causes too hot of a burn and the exhaust port side of piston takes a beating

Hole in piston to me means a hole in middle of piston not the side,
Running too hot of a plug or pre ignition due to timing or fuel octane too low due to the ethanol fuel separation and leaving bad gas

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

My thoughts are lack of oil will usually get bearings 1st, so premixing will not solve that piston failure
lean on fuel or overheat will get piston like that
lean causes too hot of a burn and the exhaust port side of piston takes a beating

Hole in piston to me means a hole in middle of piston not the side,
Running too hot of a plug or pre ignition due to timing or fuel octane too low due to the ethanol fuel separation and leaving bad gas

i was thinking on that but the standards of gas here are different
and thats why when u.s. engines come to mexico they have some troubles
well thanks

talking about that yesterday a new costumer bring a ranger with a 300 hp yamaha vmax like the other he was so happy
this morning the engine blew up
the block has a hole in cil. #4

 

[juan carlos estrada]

Re: Yamaha 250 HPDI Rebuilt PH BUrnt Piston Issue

ahh by the way can someone send me a torque spec. table plz for yamaha vmax
i have one but i want another it will be helpful
thanks...