aluminum on plugs

[DAN M VAGOS]

hi all new to boating just got a free 16' glastron with a nice merc (1987) 70ph on it runs great. just put it in the water ran great 2 hours then ran out of fuel so i just puted back to dock maybe 15 min. so now today i brout it out and it ran like crap so i puled the cover off and found the #3 plug had some aluminum on it so i put one of the old plugs in bc i just put these new ones in and it ran great agen no problems at all ran 3 hours. then when i got it home i pulled that plug and not a thing on it plug looks real good so do you think thers a mager problem i allso looked in that cyl and the piston looks good and the cyl walls look real good please help.

 

[Chris1956]

Re: aluminum on plugs

Aluminum on the spark plug means the piston is melting. I recommend you check your link and sync, and if that is set properly, check the carbs for clogged jets. Normally your condition is caused by over spark advance or lean mixture.