2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

how that EFI system oils is by mixing the oil with the gas in the VST. I would guess you have a partially clogged injector that ran a cyl lean.
you have at least 1 cyl that must be bored oversize now.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

dsdfgsdfg
 
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rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

doesnt look like an oil related failure.
looks like a lean out due to a defective O2 sensor or an injector screen.
remember the oiling on the OX66 is via the fuel injectors.
if the bearings and journals are not discolored or pitted then typically they are good.
ALWAYS replace the bottom main.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

I have a Yamaha manual but I cannot find a compression spec in psi. Do you know what it is for that motor?

Thanks
 

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

there isnt a spec. its a 10 PSI maximum variation from bank to bank.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

Ok, now I'm really stumped... I removed the powerhead, replaced the piston and reinstalled on the boat. I have hooked all the wiring harnesses up and now it seems like Im not getting any spark. The motor turns over great and seems like its getting fuel. I have double and triple checked all the connectors and ground wires and it seems like I have everything connected right but the boat wont start. I used an automotive in-line spark checker and I do not get anything. I have researched and found other comments on "homemade spark checkers" but I would assume this would work like it does on a car. Any ideas? How would I check for power to the CDI unit? I have also checked the lanyard and as soon as I remove the buzzer goes off so it seems to be working. The boat ran perfect other than the knock sound before I started this adventure so I dont think there was any preexisting ignition or fuel issues?
Any ideas? Thanks for the help.
 

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

check the pulser coil and the ECU grounds. they can be easily overlooked.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

No dice. I checked both and cannot find any open grounds.
How would I check for power at the cdi?
 

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

if you lose the pulser coil ground you lose all 6 pulsers.
that means no spark and no fuel injection.
if you lose power to the ecu you lose the ECU but it will still inject fuel and spark although it will be in bypass mode.
if you lose the ECU ground you may or may not lose spark but you will lose fuel injection and the HP pump will not run at key on power.
myself I would check stator charge coil outputs and pulser coil outputs first.
does the fuel pump turn on and whine for 3-5 seconds at key on power?
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

Yes. The fuel pump comes on with the key for a few seconds. I tested the voltage across the two terminals on the hp (in vst) pump and I have 12 volts until it times out. From your previous post that would lead me to believe that I have good ECU power/ground. How do I test a stator charge coil outputs. Are you referring to the coils for each cylinder connected to the plug wire. Where and how should I test.

Is there any way I could have installed the pulser coil assembly wrong? I thought the bolt holes would only line up one way. Possibly upside down? I remove and figure out myself if the flywheel wasnt as difficult to remove.


Thanks for the help.
 

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

pulser coil assy when installed correctly will have the leads coming down the port side of the block just aft of the VST.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

If this was orientated wrong would it cause no spark? I thought it was just 3 or 4 equally spaced bolts. I'm going to re-pull the flywheel to check everything underneath one more time when I get home from work.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

I removed the flywheel and reorientated to the port side. I didn't see anything else out of place. All connections tight and no open grounds. Any other suggestions?
 

rodbolt

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

yes, like before.
test charge coil and pulser coil inputs to the CDI.
 

Todd UNF

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Re: 2004 Yamaha 200 HP Knock & Piston Damage (Pics Attached)

Just an update to this thread and a thank you to Rodbolt for the help. My motor has been back in operation and running fine for the last few weeks.
As hard as it is to admit I had a wiring harness switched. I checked every harness twice to make sure no pins were bent and all were completely connected. It appeared that every harness on the engine was unique and there was no way to connect backwards. There is one harness that is almost an extension of another harness that I had backwards. If you are having the same type of issues you may want to do a harness rundown. All Yamaha wire colors are the same of each side of a connector. I hope posting my screwup helps someone else.

Thanks again Rodbolt for the advice.
 
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