120 Mercruiser

B

Brandonbaha

Cadet
Joined
Jun 19, 2009
Messages
12
I have a 1979 120 Mercruiser i/o. Just bought it,it was sitting for appromixately 2 years. I tried to start it today after I just rebuilt the carb and it fired up right away but then it died right after. I tried again and it did the same thing. Then sometimes it will idol for about 2-3 minutes with occasional backfiring. When at idol I spray gas into the carb and it runs good as long as its at a steady pace. Then i took the sparkplugs out and they were black. Also when I go to give it gas in neutral it would bog out. Could it be the fuel pump. If you know it would be muchly appreciated! Thanks
 
J

jkgregg

Cadet
Joined
Jul 20, 2009
Messages
23
Re: 120 Mercruiser

i just recently bought a boat that sat for 2 years. i just went ahead and drained tank, rebuilt carb, changed fuel filters, and replaced fuel pump. it now runs and idles on its own and when i rev it up it sounds good. i would just suggest doing what i did. it really didnt cost that much. the most expensive part was the pump and which that only cost me 80.

i have been reading on other threads and it seems that everyone is suggesting to check timing before you do anything else. i just wanted to clean it all up. good thing i did because there was about 7 gallons of sludge in the tank.

Good luck.
 
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