why

[wireman]

I have a 1984 johnson 90hp 4 cylinder outboard,I put a new fuel line in when i bought the boat, had problem no power, worked okay last year, these last couple of outings this year i noticed lack of power again swithed to full tank worked okay till about 1/2 a tank I have to keep squeezing priming bulb to keep power up WHY.Nothing done to carb or fuel pump very green at this.HELP

 

[Bluefish]

Re: why

You didn't say if you had a built in fuel tank on board if so you my have a cracked pickup tube in the tank, when the fuel gets low you start sucking in some air.

 

[JB]

Re: why

Happy Monday, Wireman. Check out Bluefish's idea. Also check for good venting of your fuel tanks. If you have any doubts, loosen the cap.<br /><br />You might need an overhaul kit in your fuel pump, but it is more likely that your problem is related to fuel feed to the pump.<br /><br />Good luck and let us know what you find.<br /><br />Red sky at night. . . . <br />JB

 

[wireman]

Re: why

Thanks guys for your prompt replies,have 3 on board 5 gal tanks,one new plastic,other 2 are the 5 gal metal,both the plastic & one of the metal tanks had same problem,I will try the 3rd tank,but seems highly unlikely both tanks good have a problem,I will dismantel all tanks and check them out.By the way where is the fuel pump,once found just install new diaframs.Thanks Let you know what happens

 

[12Footer]

Re: why

The caps on your tanks have a small screw in the center. After hooking the fuel line, unscrew this screw a bit. It will allow the tank to vent. These tanks must be able to get air to replace the fuel as the engine burns it. If the tanks can't breathe, the vacumm inside will cause the fuel to stop flowing to the pump. The bulb will flatten-out,or go soft.

 

[adrian bick]

Re: why

Your fuel pump runs on crankcase compression, so if you were to have piston ring problems (not uncommon) you would not get strong pulses and hence not enough fuel in the carburetors. Good luck

 

[wireman]

Re: why

Well Guy's,found the problem, tried a new fuel pump for a mirror $435.00,no kit available,it's a combo fuel & oil injection.<br />Still have to install the wiring harness,to sound off alarm if oil flow stops to pump.There's been a change up from original they added these fricken wires, according to install instructions:<br />-Connect the tan wires in series with the temperature sending unit circuit,<br />-On V4 and V6 cross models, use starboard temperature sending unit<br />-On V4,V6,and V8 loop models,use port temperature sending unit.<br />Where are the temperature sending units,& cross , loop ????????.<br />I'm in Saskatchewan,Canada, so our prices for <br />luxury are high, THANKS for the info