60 hp mercury miss

shadetree1

Cadet
Joined
May 16, 2010
Messages
6
i am running a 1999 60 hp mercury when i get to wot i get a real bad miss can back it off just a little and this clears up.. the motor also starts to over heat at a high rpm, any suggestions??
i have cleaned the carbs, replaced the fuel pump, and just had to replace the water pump and housing, still with no luck

any help would be greatly appreciated!
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
Re: 60 hp mercury miss

Check to see if:(a) water pump is working correctly (b) it has the correct plugs/heat range installed (c) max timing is correct. Anyof the above can cause the problem you describe do to preignition.
 

shadetree1

Cadet
Joined
May 16, 2010
Messages
6
Re: 60 hp mercury miss

i have checked the water pump, will try the plugs and timing tomorrow.. and will repost the results

thanks!
 

shadetree1

Cadet
Joined
May 16, 2010
Messages
6
Re: 60 hp mercury miss

checked the timing today and it was advanced about 6 deg too much but since its raining here have not had time to get it back in the water as of yet. thanks for the input!
 

Jacket4life

Petty Officer 1st Class
Joined
Apr 22, 2010
Messages
382
Re: 60 hp mercury miss

Hey shade-
I could be wrong, but doesn't that motor have t-stats too?
 

shadetree1

Cadet
Joined
May 16, 2010
Messages
6
Re: 60 hp mercury miss

Jacket, yes it does but that was also replaced. It only overheats and skips when at wot can drop it down about 1/8 on the throttle and it cools right back down and runs perfect!
 

shadetree1

Cadet
Joined
May 16, 2010
Messages
6
Re: 60 hp mercury miss

Worked on this motor yesterday and I think I have it figured out! Timing adjusment seams to have cured the overheat problem and ended up replacing the rev limiter put it back in the water and she never skiped a beat! Thanks everyone for the help!
 
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