1985 90hp johnson fuel pump problem?

schang

Cadet
Joined
Oct 26, 2009
Messages
12
Hey everyone,

The boat is running almost perfect, except another problem.

When I am in gear and going forward, in about 10 seconds the fuel cuts off. I would have to choke the motor to start it again. Starts up fine. In gear and going forward, the problem happens again the fuel would cut off again. My brother would pump the inline hand fuel pump connecting to the motor and the motor will run all day but we would have to pump every ten or so seconds ( we would take turns pumping). My question is could it be the fuel pump not working right and sending fuel into the engine? Or could it be a clogged inline hand fuel pump? Or other problems, any suggestions or ideas will be very helpful. I am thinking about installing a fuel pump over the hand pump to see if it will solve my problem.

Thank You in advance,
S.Chang
 

bktheking

Vice Admiral
Joined
Jul 29, 2008
Messages
5,057
Re: 1985 90hp johnson fuel pump problem?

Pretty good chance the fuel pump needs replacing.
 

psteurer

Petty Officer 1st Class
Joined
Nov 10, 2008
Messages
366
Re: 1985 90hp johnson fuel pump problem?

Could definitely be the fuel pump. Do some simple things first: check to make sure you have the vent open on your fuel tank. Remove the big screw on the fuel pump and clean the filter screen.

Are you running okay at idle? If so, you could have a clog in the high speed jet on one of the carburetors.
 

Johnsonfan14

Recruit
Joined
Nov 20, 2009
Messages
4
Re: 1985 90hp johnson fuel pump problem?

Its definitly your fuel pump.i had that problem with my 115 johnson but once i changed it that was the problem hope this helps.
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: 1985 90hp johnson fuel pump problem?

Its definitly your fuel pump.i had that problem with my 115 johnson but once i changed it that was the problem hope this helps.

Likely, not definately until the other possible causes are eliminated.
A clogged tank vent will produce the identical symptom.

If you read these pages regular you'll see, more than once, people who were advised to change the pump, $460 later they find out the pump was good , they just had some dirt in the tank vent.;)
 

cougar1985

Lieutenant Junior Grade
Joined
Oct 7, 2005
Messages
1,023
Re: 1985 90hp johnson fuel pump problem?

Likely, not definately until the other possible causes are eliminated.
A clogged tank vent will produce the identical symptom.

If you read these pages regular you'll see, more than once, people who were advised to change the pump, $460 later they find out the pump was good , they just had some dirt in the tank vent.;)
ive also run into faulty aftermarket primerbulbs that will give you fits!
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: 1985 90hp johnson fuel pump problem?

Air leak in the lines, bad venting could well be part of it. My guess is most likely the fuel pump failing though.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1985 90hp johnson fuel pump problem?

Are you running an original type combination oil/fuel pump, or has it been converted to a standard pump where you premix the oil in the fuel?
 
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