1977 20HP Mercury Merc 200 - wont start

[cguz0146]

Hopefully someone can help me out, I have a 1977 20HP Mercury Merc 200 with a thunderbolt ignition(serial #4582276) that has ran great about two years ago, I winterized it and dewinterized it at start of season last year. It ran great for about a month and then began giving me problems. I would have trouble getting it started having to pull many times for about 20-30 mins until it would get going until one day it finally gave out. Tried several things including replacing the old fuel tank and hose, changing the oil, plugs & taking apart and cleaning the carb. It still has good compression and spark n think it might be a carb issue. I can get it to turn over & run momentarily if I spray a little starter fluid in it but the outboard just dies after the fluid burns away. I stored it once again over winter and am giving it another try now. I just purchased a carb rebuild kit yesterday that im gonna try. Does anyone have any advice for me? I would much appreciate it.

 

[achris]

Re: 1977 20HP Mercury Merc 200 - wont start

..... if I spray a little starter fluid in it ....

Never use that stuff in an outboard!!!

OK... Sounds like you've narrowed it down to fuel issues. You've used the shotgun and replaced a few things and it didn't fix the problem... So now we'll use the surgeon's method.

If it is having trouble running even after being primed, I would suspect a blockage (or dirt/gum/muck) in the carb. Remove the carb, strip it, and soak it in carb cleaner overnight. The blow out all the passages with dry compressed air. Re-assemble and test.

Chris.......

 

[cguz0146]

Re: 1977 20HP Mercury Merc 200 - wont start

Thanks for your help, I'll give that a try today.

 

[cguz0146]

Re: 1977 20HP Mercury Merc 200 - wont start

OK, the carb has been rebuilt and all parts cleaned, and we have been able to get it started, but it only remains on for a few seconds and dies out. WE have confirmed that fuel is getting thru the fuel pump and into the bowl and now suspect a problem with the inlet needle & spring or float that need to be adjusted. Once we start it we can keep the motor at idle if we spray quick mists of fuel/oil mix into the carbs intake so we know that somehow the fuel is not getting sprayed by the jet.

 

[achris]

Re: 1977 20HP Mercury Merc 200 - wont start

Did you try squeezing the fuel primer to see if that would keep it running?

 

[cguz0146]

Re: 1977 20HP Mercury Merc 200 - wont start

Looks like the problem was the float that needed to be adjusted. As soon as we adjusted it back to the manufacturer's specs & reinstalled it. It started right up with one pull . After some minor tuning, the motor is running smoother than its ever run since I've owned it.

Thanks for all your help