So long story short, engine was sticking, seizing, think it was water intrusion because of slight water droplets on plugs. It’s been freed for about 2 months now and runs( yes I’m replacing water pump since it was started dry) I’m assuming since it hasn’t been run in water or on hose, no water to cause it to stick. So I pulled the head off. Here is the head. Looks like lower cylinder has been sort of steam cleaned. Some carbon build up in middle cylinder, been using yamaha combustion chamber cleaner to get loose. Hoping to clean gaskets off, replace, and new water pump. I don’t see or feel any scoring on walls. Any thoughts? Yamaha 90 TLRZ
FIRST THOUGHT !!! * HEAD GASKET BLOWN BETWEEN WATERJACKET AND CYLINDER *
CLEAN ALL SURFACES AND PASSAGES , INSTALL NEW GASKETS AND DO A COMPRESSION TEST…ALSO NEVER,NEVER,NEVER RUN WITH NO WATER FLOW ;; GOOD WAY TO DESTROY IT !!! JUST MY 2CTS WORTH !!!
George McDonald
US Navy Seabees,Retired,
MAD, Charleston Chapter
[http://www.militaryappreciationday.org
When you see “Old Glory” waving in the breeze, know that it is the dying breaths of our fallen hero’s that makes it wave.
author unknown
gail, I only ran it for seconds and turned off. Compression was 110 on all cylinders before taking off. your suggestions are what I was leaning towards. I was actually surprised how clean the water passages were. Religiously flushed, but figured some salt would stick behind.
im not to sure, but im pretty sure…
THAT SOUNDS REASONABLE ESPECIALLY SINCE COMPRESSION IS CLOSE ON ALL CYLINDERS… A GOOD CLEANING AND NEW GASKETS HOPEFULLY IS ALL YA NEED …AFTER NEW GASKETS RE CHECK COMPRESSION FOR EQUAL PRESSURE AND FOR HOW LONG IT WILL HOLD THE PRESSURE ON EACH CYL… YOU’LL NEED TO FIND OUT FROM MOTOR MANUAL THE NEEDED CORRECT PRESSURE AND TIME IT SHOULD HOLD IT,GOOD LUCK ; HOPE THERE IS NO OTHER PROBLEMS…
GEORGE
George McDonald
US Navy Seabees,Retired,
MAD, Charleston Chapter
[http://www.militaryappreciationday.org
When you see “Old Glory” waving in the breeze, know that it is the dying breaths of our fallen hero’s that makes it wave.
author unknown
Head gasket. Pull gasket off head and clean passages. Take the water jacket cover off and do the same.
Tall Sail Marine
Looper, I always hear those are the bolts that usually snap, can I just run vinegar through those passages? I guess if im going through all this I might as well replace that gasket as well. Some friends recommend taking to simons balancing to get them to clean the parts and make sure it is a flat matting surface. Or do yall think a plastic scrapper should be sufficient? any sort of cleaning products I can use on the block surface?
im not to sure, but im pretty sure…
ERIC , IF YOU DECIDE TO PULL WATER JACKET PUT A FEW DROPS OF BREAK AWAY PENETRATING OIL ON EACH BOLT OVER THE COURSE OF SEVERAL HOURS AND EACH TIME GIVE EACK BOLT HEAD A LIGHT TAP OR TWO JUST HARD ENOUGH</font id=“red”> TO JAR IT TO ALLOW OIL TO SOAK INTO THREADS. THIS MIGHT BE A BETTER JOB LEFT TO A GOOD REPAIR FACILITY… YA MIGHT WANT TO GIVE CHRIS V A CALL…
George McDonald
US Navy Seabees,Retired,
MAD, Charleston Chapter
[http://www.militaryappreciationday.org
When you see “Old Glory” waving in the breeze, know that it is the dying breaths of our fallen hero’s that makes it wave.
author unknown
i would not start with removing the waterjacket.
Those bolts are notorious for breaking off.
To my knowledge there isnt a “time” to hold compression on these motors.
you could always do a leakdown test, but its kind of pointless on a 2 stroke that shows good compression.
the key question is…
where was the water coming from?
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IF I RESPOND IN ALL CAPS, ITS NOT ON PURPOSE, AND I AM NOT YELLING
I scrape them. then wire brush them, then emery cloth on a smooth surface. I also decarb the pistons with decarb and wire brush. Do it when piston is tdc.
Tall Sail Marine
based on what I see, it looks like the very bottom of the bottom cylinder is where the water intrusion is coming from. I have tested my fuel going into the motor and there isn’t any water bubbles in the fuel. the gasket sort of has a bump in it that seems like it was pushing itself away from the surface of the block. I have noticed a few water droplets inside the cowl underneath that area, always thought it was from spraying motor down… that’s my guess. (last photo for reference)
im not to sure, but im pretty sure…