Mercury 4HP/4Stroke Runs rough at speed

T

twosailin

Recruit
Joined
Jul 17, 2009
Messages
3
I have a 2002 Merc 4HP/4 Stroke. It starts fine, idles great. In nuetral engine seems to run fine. When put in gear it still idles and runs OK at low RPMs. When given more throttle in gear it seems to bog down/miss. Pulling the choke out just a 1/8-1/4 inch it runs great. The fuel is new. What causes this?
 
W

whyboats?

Cadet
Joined
Jul 17, 2009
Messages
14
Re: Mercury 4HP/4Stroke Runs rough at speed

sounds like it's not getting enough fuel. when you pull the choke out, you are richening the fuel mixture. I assume it has a carb? if so, it sounds like it's got some dirt in it. probably a blocked or partially blocked jet. You can try a fuel system cleaner but I would tear it apart and clean it.
 
T

twosailin

Recruit
Joined
Jul 17, 2009
Messages
3
Re: Mercury 4HP/4Stroke Runs rough at speed

I did take it apart and have found some junk in it. I guess I will tear it apart again. Could the float not be adjusted properly and not allow enough fuel under load? Thanx to all..............john
 
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