1989 Merc 70 ELPT cranks then dies.

[whopperstopper]

I pump up the primer bulb and can see gas in the gas filter but it drains back to the tank in a few seconds. As long as I pump the bulb, the engine will run. <br /><br />There are no gas leaks anywhere. I have not replaced the end fitting on the hose but it does not leak. The primer ball is new (Mercury brand) as is the gas line. <br /><br />I removed the VRO tank and have oil in the gas tank.(new gas tank) The oil line to the fuel pump is not plugged but it does not run any better when I hold my finger over the hole. Gas still runs out of the filter(on the motor)just as fast.<br /><br />What am I missing? Do I need a new fuel pump?<br /><br />Engine has 14 hours. Hasn't been in the water since 1990. I've re-built Carbs, changed water pump impellor, and changed oil in foot.

 

[achris]

Re: 1989 Merc 70 ELPT cranks then dies.

KKen,<br /><br />Did you change the diaphrams in the fuel pump? Also look at the 'o'rings in the fuel fittings. At that age they could be leaking air into the system. But the pump would be the first thing I'd do.<br /><br />Chris............

 

[whopperstopper]

Re: 1989 Merc 70 ELPT cranks then dies.

Nope, I haven't pulled the pump. Is it a big job?

 

[achris]

Re: 1989 Merc 70 ELPT cranks then dies.

Nope! dead easy.<br /><br />Follow this thread, I explain how it's done.... <br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=29;t=012957;p=1#000012 <br /><br /><br />And you have the 4 hose system, even though you'll only have 3 hoses running into the pump.<br /><br /><br />Chris..........

 

[Elmer Fudge]

Re: 1989 Merc 70 ELPT cranks then dies.

it could also be a bad check valve in the bulb.

 

[achris]

Re: 1989 Merc 70 ELPT cranks then dies.

Nope! Bad check valve would cause one of two faults, neither of which have been described.<br /><br />Fault 1. A check valve closes completely. Symptom. No fuel gets to engine at all.<br />Fault 2. A check valve fails to seal. Symptom. Primer fails to pump fuel. Engine can suck fuel, primer can't push fuel.<br /><br />Sorry, got strip that pump.<br /><br />Chris...........

 

[whopperstopper]

Re: 1989 Merc 70 ELPT cranks then dies.

Thanks. I'll get a kit ASAP. Kinda neat to get the answer from the other end of the world.