1971 Mercury Won't Start

[mcconnell63]

My 1971 65hp Mercury won't start. About 1 1/2 yrs ago maybe more I bought the boat and the motor fired right up. There was a leak in a fuel line so I replaced all the hoses. I haven't tried starting it again until last week. Could there be a build up of varnish in the carb preventing it from starting. I asked my boat machanic about this problem and he thinks the carb is gummed up. My question, if I use fresh gas and a new battery, is the anything I can put in the gas that would clean out the carb when I pump the fresh gas into it without starting it.Say let the gas sit in the carb for a couple of hrs. before trying to start it. Thanks in Advance for any help. Al

 

[Chris1956]

Re: 1971 Mercury Won't Start

If you let it sit with gas in the carbs (versus running it dry), you may have some gunk in the carbs. The only way to clean it is to take 'em apart and spray the passages with carb cleaner.

Let's start with the basics, pull the spark plugs and clean 'em up. Put a wire on one of them and hold it on the block and crank the motor to see if you have spark. If so, reinstall the plugs and choke the daylights out of the motor and try to start it. Spray some 50::1 fuel mix into the carb intakes. After she fires up let her warm up and see how she runs. If it is rough, then the carbs likely need cleaning.

 

[tmcalavy]

Re: 1971 Mercury Won't Start

Sat for 1.5 years with gas in the carbs...any idea how old the gas was then? Priime candidate for pulling, hand cleaning the carbs...not a hard job, just work on a clean surface and go slowly and keep your eye on how the parts come off. After you get them clean, re-installed, synch the carbs to the timing and run some Sea Foam in your gas to keep the system clean. Fog it for storage before you put it away for awhile.

 

[mcconnell63]

Re: 1971 Mercury Won't Start

THANKS FOR THE HELP GUYS, Al