Yamaha 80 4stroke, 2002. HELP

[Shipway]

I have a 2002 yamaha 80 4stroke and am having some issues. If you have any insight, it would be greatly appreciated.

first. compression is perfect on all cylinders, never sunk, around 700 hours, change oil more than regular, and winterize every year.

I seam to be getting water in my bottom cylinder and a bit in the oil. It happens after i go for a run and then stop. it sputters and isnt firing on the bottom cylinder, but then burns water out and runs fine. I thought it might be some backwash negative vacuum from stopping to abruptly, but I have tried slowing down every which way. with no change.

any ideas?

[seabob4]

Could this be possibly related to the infamous Yam 225 exhaust corrosion issue, where the water jackets get corroded through?


Just a thought...

[Shipway]

thanks for the reply
what would that mean.
Ive also heard that it could be the oil pan gasket, which of course means serious disassemble..

[seabob4]

Are you familiar with THT?

[Shipway]

no?

[seabob4]

http://www.thehulltruth.com/search.php?searchid=6543335

Take your pick.  Not saying your little 80 has the same issue, but...it does come from the same family...

[futch13]

Have you done a leakdown test?  Sounds like a head gasket.

[Georgie]

Sounds like a head gasket.

That was my initial thought as well, as water in the cylinder is a classic symptom of head gasket failure, but please let me qualify this by saying I know Jack Diddly about 4-strokes.  

[futch13]

Sounds like a head gasket.

That was my initial thought as well, as water in the cylinder is a classic symptom of head gasket failure, but please let me qualify this by saying I know Jack Diddly about 4-strokes.  

Everyone preaches compression test but on a 4stk unless there is "major" failure, the compression can be within the 10% rule and have a problem.  I have almost thrown my compression gauge away when it comes to 4stks.  It takes just a little longer to do a leakdown and the results give you a lot more info on the internal conditions of the motor.

[GoneFission]

90% probability of head gasket.  And don't wait too long to fix it or you will have cylinder issues that will require reboring or worse.  Head gasket on this motor is not a real big deal.  How confident are you with basic tools, torque wrenches, timing settings, etc.?  Get a manual and see if you want to take it on - otherwise, find a good tech and get it fixed.  One thing for sure - it is not going to get better on its own...

[Shipway]

Thank you all for your insight.
Ya head gasket was my immediate thought, but the compression is bang on.
I haven't heard the term "leak down test"..I'm not a mechanic, but owning motors has forced me to learn lol.
I hope it's the head gasket..that's a quick fix.
And she has been flushed and winterized right after the problem showed up. Summer boat.
Thanks again I'll you tube leak down test