4.3 Mercruiser Motor lost power

F

feely21

Recruit
Joined
Aug 19, 2009
Messages
1
I am having issues with my 1986 mercruiser 4.3 If it sits in my driveway, iput the muffs on it will fire right up, but yet if i trailer it 10 blocks to the lake it fights me to start, I changed the filter screen that is in the carb the other day and found sediment in there and now i cannot seem to get over 2200 RPM's out of it and yet it will still start right up in the driveway but yet again when i take it to the lake it fights me, I think my tach is bad cuz it seems like i am getting more than 2200 but i know its not anywhere near the 4400 to 5300 that is com mon for the boat any help greatly appreciated.
 
G

grahamh

Petty Officer 2nd Class
Joined
Aug 10, 2009
Messages
192
Re: 4.3 Mercruiser Motor lost power

Admittedly I'm not familiar with the boat, but if you're getting sediment at the carb, you AT LEAST need to change your fuel filter, it's probably really dirty. Maybe driving is stirring up sediment in the the bottom of the tanks?

Just a guess.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,459
Re: 4.3 Mercruiser Motor lost power

Ayuh,... When was it's last Tune Up,+ Service,..??
 
R

ramster

Petty Officer 2nd Class
Joined
Jun 19, 2005
Messages
150
Re: 4.3 Mercruiser Motor lost power

My guess is the main jets are dirty, when your in the driveway running it there is no load on the motor so it needs little fuel to run, but when your on the water turning the prop and putting a load on the motor, it can't get enough fuel. Take the carb off and give it a good cleaning.
 
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