Fuel problem

jbsiv

Cadet
Joined
Aug 25, 2009
Messages
21
I have a 1976 40hp Johnson and I am wondering how you increase the flow of fuel to the engine. Is the only way to adjust the float or is there a way to adjust it without taking apart the carburator? I fit is the float, how do you do it?
 

gazza2007au

Chief Petty Officer
Joined
Mar 9, 2007
Messages
429
Re: Fuel problem

a float just maintains the fuel level in your carby it doesnt control how much fuel your engine gets it controls how much fuel your carby gets as u open up the throttle the float lowers allowing more fuel to come into the carby refilling it than it rises and stops the fuel flow untill its needed again
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: Fuel problem

An odd question. Why do you want to increase the fuel flow. What problems are you having.

The float since you ask about it controls the fuel in the carb to the correct level. Generally the float closes the needle valve when it is horizontal . It is checked by turning the carb upside down but you need to refer to the workshop manual for details and to confirm that "horizontal " is correct.

If you are not getting adequate fuel flow the likely reasons are restricted tank vent, restricted fuel pick up (filter in tank??) air ingress into fuel line esp at connector, choked fuel filter on the fuel pump, a defective fuel pump or blocked or sticking needle valve
Several of those will be overcome by gentle pumping of the bulb.
Are your troubles symptoms of a carb in need of cleaning. That can often be diagnosed by operating the choke or primer. If it runs partially choked it almost ceratinly means the carb needs cleaning.
 

jbsiv

Cadet
Joined
Aug 25, 2009
Messages
21
Re: Fuel problem

My problem is I cannot get the motor up to full speed. i had it running great but now it will not get enough speed to even plane out. It starts up great and I can run a low speeds but when I try to throddle it up the boat seems bogged down and seems loke it is trying but will not set up to speed.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,398
Re: Fuel problem

Check fuel pump functionality and clean the carb's
Go from there.
 
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