moisture on plug

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eric m

Cadet
Joined
Jul 13, 2010
Messages
7
My problem began with a hesitation that i had when i was trying to get my boat to plane off. I first thought it was water in the gas , but i eliminated that hunch. now after a couple of plug changes ,i decided it was the headgasket , so last night i pulled the head off cleaned the head and block and inspected everything. sure enough there was moisture in the bottom two cylinders. the old headgasket looked pretty good where it seals the cylinder to the head. It was shiney and smooth like the new gasket . I figured it would have been obviously defective looking . I decided to take a shot in the dark and put the new gasket on and hope it would work. Well it didn't! I torqued it to spec , put in new plugs , and still moisture on the plugs. now it also weaps around the head too. I'm thinking that now it's time to pull the head again and have it surfaced and put on another headgasket.Does this sound like the next logical thing to do? the motor is a 1994 yamaha c75tlrs 3 cylinder 2 stroke.
 
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birdseye418

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Joined
Jul 3, 2008
Messages
22
Re: moisture on plug

man I feel your pain! Going through the same problem w/my90 yamaha
bottom plug gets wet
I first thought gasket and changed it, then when I still got water on the plug I used a portable tank withfresh fuel hooked directly to the motor and ran 5 gallons with same results. My head gasket also looked tightly sealed when I removed it. you said yours leakes after replacement, did you pinch the ground wires on the bottom?
I'd really like to know what's going on. I'm 99.9% sure I didnot over heat my motor. I'm supposed to go scalloping in two weeks, looks like I'm not going to make it.
 
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eric m

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Jul 13, 2010
Messages
7
Re: moisture on plug

It turns out that i did pinch a coil wire next to the middle cylinder (thats what i get for doing the job at night ).I have to wait a couple of days for a new gasket , so i decided to to try again with the same gasket. Took it on about a 3 mile run this morning and it did great. The hesitation that was my beginning issue went away .the only problem it had was that It did keep wanting to stall when i tryed to push it all the way up on the trailer with the motor ( it's never done that before). When i got home i checked the plugs and the bottom one has moisture on it again :mad: I'll go run it again in a couple of days to check the hesitation and moisture again!
 
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99yam40

Fleet Admiral
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Sep 7, 2008
Messages
9,116
Re: moisture on plug

and let the moisture rust the internals of the motor while you wait?
 
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birdseye418

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Jul 3, 2008
Messages
22
Re: moisture on plug

At this point I'm going to have to let a TECH figure out what's going on with my 90. I'll post the results when I get them. i'm afraid I have a crack in my cylinder wall.
 
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eric m

Cadet
Joined
Jul 13, 2010
Messages
7
Re: moisture on plug

I ran it today and the hesitation is back.
this is what a local yamaha tech told me
"there are other sources of water, could have some seeping through a water jacket into the exhaust cover, ive seen more issues here than heads,,,"

I'm going to take exhaust cover off in the next couple of days . He said there could be a small hole in the baffle inside the cover and that it is probably the culprit. I'll let you know how it goes.
 
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fish46

Seaman Apprentice
Joined
Jul 13, 2009
Messages
31
Re: moisture on plug

hey eric m did you get you problem fixed i have a 90hp Yamaha 1986 with a similar problem. it started to stall on take off or feels like not the same power like before. last time i went out it over heated. when i got home checked plugs and found water in bottom cylinder. took head off and gasket doesn't look like problem. i was thinking of changing the head and exhaust gasket to see if it takes care of problem. i cant think from anywhere else the water can come from.
 
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eric m

Cadet
Joined
Jul 13, 2010
Messages
7
Re: moisture on plug

The exhaust plate completly fixed my problem! No more hesitation. The whole repair cost less than $50.
 
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birdseye418

Cadet
Joined
Jul 3, 2008
Messages
22
Re: moisture on plug

eric m said:
The exhaust plate completly fixed my problem! No more hesitation. The whole repair cost less than $50.
Click to expand...

just got mine out of the shop $275.00 later.
I wish I had the confidence in my mechanical skills I'd rather have paid $50 and done it my self. I got tired of throwing crap (gas, head gasket) against the wall hoping somthing would stick.
Atleast we're back on the water!
 
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