20 hp merc,idle and take off problems

jacksok1

Recruit
Joined
Apr 18, 2007
Messages
3
idles rough and when you start to take off it boggs down and dies,acts like it's running out of gas.If you ever get took off runs like a charm,but when you let it idle for a couple of minutes and try to take off same thing.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 20 hp merc,idle and take off problems

clean and rebuild the carbs.
 

stompie

Cadet
Joined
Apr 11, 2007
Messages
21
Re: 20 hp merc,idle and take off problems

I had a similar problem. If it idles rough and dies under load....check your compression. My motor compression was down on two cylinders and eventually required a rebuild. Do carbs first as this may help but check compression while you are at it. Mine used to start and idle no problem... just a bit rough. As soon as it was in gear and started accelerating it cut out. Once you managed to get it going it ran like a scalded cat.

Good luck
 

Jugfisher

Petty Officer 3rd Class
Joined
Apr 19, 2007
Messages
83
Re: 20 hp merc,idle and take off problems

I agree with Stompie. Check compression. I spent alot of money thinking that it was a fuel or fire problem on my 70 hp merc but turns ou that the #1 cylinder was in pieces. If you ever have a problem always good to check compression first. A compression tester can be inexpensive but you get what you pay for. If you can I would atleast get a mid-grade compression tester wich would be about 30-50 dollars.
 

Windykid

Lieutenant Junior Grade
Joined
Apr 17, 2007
Messages
1,177
Re: 20 hp merc,idle and take off problems

How about the basics, Try pumping your fuel bulb first while takeing off. Check the color of your spark plugs. Check compression. Rebuild carbs. Decarb.
 
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