77 Evinrude 70hp fuel pump question

[nosfedgta]

Hey.. so I noticed a strong fuel odor the other day. Upon inspection I found my fuel pump housing was cracked. I ordered a new fuel pump and when I got it I noticed that it had the 3 nipples and a vacuum port on the back, but mine had the 3 nipples and no vacuum port on the back. Can I just block that vacuum port on the back of the pump off ?

Drew

 

[racerone]

Fuel pumps operate on a PRESSURE pulse not vacuum as such.-----So what part # pump did you get ?----And have you checked that the port on the back actually goes to the diaphragm ?

 

[nosfedgta]

Ordered from a company called carbstar 392721685775 is the number it said was for my engine

 

[racerone]

Does the port at the back go to the diaphragm , yes or no ?-------Or test it this way.----Blow into the nipples.----Does any air come out the back , yes or no ?

 

[nosfedgta]

Yes air comes out of the back.

 

[racerone]

You would need to mount that pump with a gasket to block that hole.------I am just not sure on all these " fits everything " deals found on line.

 

[nosfedgta]

Well now I'm really confused. I just had my carbs rebuilt. All new fuel lines, new fuel pump "I blocked the hole" and now it wont hardly run at all.. it ran 10xs better with the leaky fuel pump..lol.. wth.. when I go to full throttle it just bugs down and shuts off... dang this thing!

 

[racerone]

You paid somebody to have carburetors rebuilt ??-------So what was the motor doing before the carburetors were rebuilt ?----Who decided that the carburetors were at fault ?------You are sure that hoses are routed correctly.---What other trouble shooting was done ?-----Note----I am not there to see , feel or hear your motor

 

[nosfedgta]

Carbs were leaking, boat would be going and then would bog down, and then all of a sudden pick back up again. Like a piece of trash was in the fuel line or carbs.

Fuel pump housing was cracked

Now all of that has been rebuilt, replaced, and all new fuel lines and primer bulb and it worse.. now it wont even accelerate. As soon as I hit the throttle it bogs and shuts off....

Just tired of spending money on parts for a problem to just get worse.

On a side note it only does this under load. It does not do it while idling or while have the rabbit ears on them with water flowing and in gear or pressing the throttle down.

 

[racerone]

On rabbit ears the propeller might be spinning but really it is still neutral as the is no water to provide a load.-----I say you need to test compression on the motor.----And see if spark will jump a gap of 3/8" or more on each lead.----Sounds like motor is running on 2 of 3 cylinders.