Intermittent power loss, water leaking out between upper and lower unit casing

[yktim]

I have a 1993 Yamaha 225 hp 4 stroke 6cyl. While running the boat yesterday, I would loose <br />power then it would run fine, loose power, run fine etc. I then noticed water comming out through the joint in the casings between the upper and lower units. Any Ideas?

 

[rodbolt]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

can we get a model number. in 93 they made no yamaha 6 cyl 4 strokes or at least none for the US market.

 

[yktim]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Sorry, Wrong Information. Corrections as Follows<br />Yamaha 1993 250 HP model 250 TXRR V-X 76<br />Removed cover while running motor. First air and then water is comming out from one top spark plug. Motor starts on 1st try.

 

[rodbolt]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

now I am confused<br /> you removed the hood. I am with ya. how did ya get air then water from a plug ?<br /> if you removed the plug and cranked it and had water coming out of the actaul spark plug hole its most likly a blown head gasket. if its leaking just beside the plug with the plug still in its most likly a failure of the water cover gasket or cover or head.

 

[yktim]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Thanks Rodbolt, you hit it on the "head". Air then water was comming out next to the port side top plug while it was still in. Removed head cover and head to find small corrosion hole in head next to spark plug. Removed other head just to check it out. Minor corrosion evident, will be replacing both heads and covers. Any advice on procedure ?

 

[yktim]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Can anyone advise on procedure to replace heads, covers and gaskets<br /><br />Thanks

 

[rodbolt]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

carefully clean all surfaces, use perfect seal on the gaskets and the correct torque on the bolts. check the block and head pencil zincs while your in there.

 

[yktim]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Thanks Rodbolt,<br />Pencil zincs were a little corroded, will replace all.

 

[yktim]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Hey Rodbolt,<br />Thanks for your help. Replaced both heads, covers and all four zincs. It took my buddy and I about 6 hrs to complete. Good thing we don't get paid by the job. Motor is running great.

 

[rodbolt]

Re: Intermittent power loss, water leaking out between upper and lower unit casi

Re: Intermittent power loss, water leaking out between upper and lower unit casi

see how much fun it is <br />and I actually get paid for doing it