Classic 45 Merc wont pump fuel consistantly FIXED!

[imported_bowfisher]

Heres the facts.... Mercury 4cylinder, 2 carb, fuel pump on the side of the carbs, 50 hp outboard

New fuel tank, new fuel line and bulb, new connector, rebuilt carbs and fuel pumps, all new fuel lines on motor except for one.

Motor starts easily, runs in the tank even at higher RPM. Put it on the water, pop in gear and get on the gas, motor bogs after a few seconds until the bulb is squeezed.

Could the new diaghrams been weak or at least one of them anyway? Appears to be NO restrictions anywhere to the carbs and the tank is vented, connection tight with no fuel leaks anywhere.

*Scratching my head*

Thanks!!

 

[Faztbullet]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

If the one of the carb base gaskets is installed improperly it will cause that carb not to pump as gasket has a hole in it to allow crankcase pulses to diaphragm....
Google Image Result for http://cdn.boatersplus.com/images/product/87/18-2800.jpg

 

[imported_bowfisher]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Sorry, I forgot to mention, yes the carb gaskets are installed properly. Thanks!!

 

[bgc]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

What year is she?

 

[imported_bowfisher]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

I would guess late 80's to early 90's without checking

 

[BatDaddy1887]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Maybe replace the fuel filter near the engine (if it has one) or replace the water separator filter (if it has one). Always put half-a-can of Seafoam in every other tankful or so to keep all parts clean as a whistle. I heard that Mercury outboard fuel line and bulbs are the best to get as the bulb has a flange on both ends instead of just one side.....

 

[on_ice]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

How do the fuel pumps work? I have the same motor and I took the carbs apart today and it doesnt exactly seem like there is a fuel pump on the side of each carb. The manual states it does but I'm not convinced they are talking about the same motor.

 

[on_ice]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Are you setting the idle with it in gear and in a bucket of water? You need that resistance or else the engine will die once the extra resistance is there from the water.

 

[BatDaddy1887]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Here is where my fuel pump is located.

 

[on_ice]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Same with mine. Is that the 115 in your signature? I see you have the "A" carbs they have in the manual. Mine are no where to be found in the manual but somewhat resemble the "B" carbs.

 

[imported_bowfisher]

Re: Classic 45 Merc wont pump fuel consistantly

Re: Classic 45 Merc wont pump fuel consistantly

Here is what I found...... previous owner had the motor worked on at a marina, they replaced one of the carbs (why I have no idea) the carb that was replaced was not identical to the original. The replacement carb had a .05" main jet, the original had a .056. I removed the (replacement) and attached a carb with a .055 jet. Also replaced all fuel lines again just in case there was something I over looked. Boat now runs properly. Still not sure which fixed it but am pretty sure it was the jet size.