melted piston!

jeff9501

Cadet
Joined
Jul 23, 2010
Messages
13
here is the background on my boat and motor.

Hi I have just purchased a 1973 glastron boat with a 1973 115 mercury outboard engine . The person who I bought it from has owned it for a number of years . He said he started it this spring and it ran great I just bought it a week ago . He started it when I was there and I heard it run sounded ok . I had it in the water a few days later at first it didnt want to start I saw some fuel dripping out the engine cover I put the engine all the way in the water and it started it worked great that day ! I had it out the other day I squeezed the primer ball a bit tried to start the engine cranks over good but no start . I saw fuel again dripping out of the cover I thought it was just flooded and if it sat for a bit it would probably start right up. No such luck after a about an hour and still no start I towed it home depressed ! The next morning I tried again with a garden hose attached at home .. still nothing after a bit of investigation it seems that I hAve NO SPARK . So this is the point I am at the repair shops are all 4 weeks behind so I need to take care of this somehow my self .. this is an older engine with a disributor cap so any Ideas or suggestions that might get me out fishing would be greatly appreciated ......................Jeff


Any ways I got the boat running again all was good so I thought . The last time I used my b oat it wasnt running very well bogging out and not reving to WOT . A while later I was going from boat to boat and I hurt myself very bad my knee is a mess ! I have recovered a bit now and thought I might go fishing tomorrow. long story short I bought some new spark plugs for my motor uponb removing the old ones I noticed melted aluminum (i think ) stuck to the plug.... again fcuk any ways i have a melted piston in my 115 merc 1973 vintage i...
now my question
I am very mechanical how hard is the piston replacement and any thing I need to watch out for??
ny where |I can get online repair manuals??


any one have any help for me thasnks in advance Jeff:cool:
 
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Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,081
Re: melted piston Fcuk!

Re: melted piston Fcuk!

Do a compression test.
 

chum1

Petty Officer 1st Class
Joined
Apr 15, 2010
Messages
359
Re: melted piston Fcuk!

Re: melted piston Fcuk!

go to the stickies at the top of the forum, you should be able to find a manual there sorry to hear your problem :(, something was probably plugged or mis adjusted and running lean and/or the timing was off.
 

jeff9501

Cadet
Joined
Jul 23, 2010
Messages
13
Re: melted piston!

Thanks everyone .
I found a person who has some nos parts he has a piston for my engine now is 75 a good price for the piston ,pin and rings ??
thanks
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,089
Re: melted piston!

Jeff, a new piston and ring set is about $100. Make sure the piston is oversize, as you will likely need to bore out the cylinder to clean up the scratches.
 

joed

Lieutenant Junior Grade
Joined
Sep 28, 2002
Messages
1,135
Re: melted piston!

Did you figure out why the piston burned up(not enough oil, mixture too lean,etc.)? If not then your new one might burn up as well.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,089
Re: melted piston!

Jeff, Joed is correct, except where he says "might". if you do not determine why the piston was damaged, and fix the issue, it "will" happen again.
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: melted piston!

I think most of time you will have a lean fuel/air condition to hole a piston.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,089
Re: melted piston!

Pistons will melt due to lean fuel/air mix, overadvanced ignition timing, poor cooling or some combination of all three. On the inline sixes, #3 usually melts first, followed by #1.
 
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