1972 40 hp Johnson fuel question.

[mikietoo]

Just got this boat. Doesn't start under normal condition. Will start with some priming (squirt a little gas into the carb throat). In checking fuel, when I pump the primer bulb, I can get fuel to the hose on the input side of the filter/pump but no fuel comes out of the pump/filter. To me, this means that I am not getting any fuel to the carb. Am I diagnosing this right? If so, is it much trouble to repair the pump? Filter/screen is clean.

 

[Joe Reeves]

Re: 1972 40 hp Johnson fuel question.

Proper check...... Remove fuel hose from fuel pump that connects to carburetor. Pump primer bulb. Fuel should flow out of carburetor side of fuel pump. Is this what you're doing?

 

[F_R]

Re: 1972 40 hp Johnson fuel question.

Just got this boat. Doesn't start under normal condition. Will start with some priming (squirt a little gas into the carb throat). In checking fuel, when I pump the primer bulb, I can get fuel to the hose on the input side of the filter/pump but no fuel comes out of the pump/filter. To me, this means that I am not getting any fuel to the carb. Am I diagnosing this right? If so, is it much trouble to repair the pump? Filter/screen is clean.

"Fuel will not come OUT of the pump/filter" you say? Sounds to me like you got the hoses swapped. Fuel is supposed to go IN the plastic filter cap, and out the other fitting, then to the carburetor.

 

[mikietoo]

Re: 1972 40 hp Johnson fuel question.

yes. When I pump the primer bulb, I get fuel to the hose from the tank where it connects to the fuel pump. I do not get any fuel from the fuel pump nipple where the hose that goes to the carb connects. The primer bulb does not get tight. It continues to squish.

 

[Joe Reeves]

Re: 1972 40 hp Johnson fuel question.

As F_R states..... The incoming hose connects to the plastic filter cap fitting. Are your fuel hoses reversed?

 

[boobie]

Re: 1972 40 hp Johnson fuel question.

Is the diaphram in the fuel pump ruptured and all the fuel is going into the c/c ??

 

[mikietoo]

Re: 1972 40 hp Johnson fuel question.

NICE CATCH!! The hoses were reversed. The guy I got it from said it would not run. Now we know why. Next problem. I only ran it for a few seconds because I did not see water coming out anywhere (i have in in a trash can). I don't know where the water comes out on this engine.

 

[F_R]

Re: 1972 40 hp Johnson fuel question.

See the big hole in the rear of the midsection about half way down? The one where exhaust blows out of. Water should be blowing out there too, in big healthy spray, being blown by the exhaust.

How deep in the water do you have it? See that bulge about 4" above the flat anti-cavitation plate? That is where the water pump is located, and must be at least a couple inches below the water before starting the motor.

 

[mikietoo]

Re: 1972 40 hp Johnson fuel question.

I'm starting a new thread. this is a different question.

 

[Tim Frank]

Re: 1972 40 hp Johnson fuel question.

You may want to verify that the fuel pump is working OK.
With the hoses reversed you MAY (not for certain, but maybe) have damaged the pump when you kept squeezing the primer bulb.