seahorse 4 hp fuel pump. I have a question!

[favre04]

Can anyone tell me if a fuel pump can work just at 50% or it's impossible? The way I see it is that either it works or not, but it can't work just a 'little'. AM I right?
The pump is on a seahorse 1974 4 hp . IT's a kind of diaphragm. I opened it, it looked clean and when I pushed on the diaphragm it squirt and seems to suck in at the other end. Thanks for your answers Iboaters!

 

[bktheking]

Re: seahorse 4 hp fuel pump. I have a question!

Sure they can, pin hole or small tear in the diaphram and it will still pump but will also fill the crankcase with fuel.

 

[F_R]

Re: seahorse 4 hp fuel pump. I have a question!

ANY, and I mean ANY leakage between the fuel pump and the level of the gas in the tank will admit air bubbles that will really zonk the fuel pump efficiency.

The pump must be right side up.

What kind of check valves were in the pump? The rubber flapper kind were garbage and did not pump well.

Finally, how low below the motor is the gas tank? It can't lift gas more than a couple of feet.

 

[favre04]

Re: seahorse 4 hp fuel pump. I have a question!

The pump must be right side up.

What kind of check valves were in the pump?

Finally, how low below the motor is the gas tank? It can't lift gas more than a couple of feet.

Ok I'm pretty sure the pump is right side up, I found the part diagram on crowleymarine.com

What is the check valves? I have probably seen them but what do they look like?

The tank was 2 feet below the engine and it ran well at low RPM but kinda slow at high rpm.

Any idea?

 

[F_R]

Re: seahorse 4 hp fuel pump. I have a question!

The good valves are the little metal discs. The rubber flappers are just that--rubber tabs of diaphragm material.

Can you raise that tank as a test? Will it run better if you "help" the fuel pump by squeezing the primer bulb?

 

[favre04]

Re: seahorse 4 hp fuel pump. I have a question!

Can you raise that tank as a test? Will it run better if you "help" the fuel pump by squeezing the primer bulb?

Great idea! I.ll try tonight! That forum is great because of guys like you! I hope they pay you or give you something in return! Good job

 

[favre04]

Re: seahorse 4 hp fuel pump. I have a question!

Ok! I checked the gas tank level and other things to find that when I got out the low and high speed needles there were dirty and something was stck on them. So, I checked on the diagram part ( http://www.crowleymarine.com/johnson-evinrude/parts/31455.cfm )
and realised that the black **** was probably 2 o-rings or rubber washers dried and they turned to some ****. So I ordered 4 of them today. I also noticed that a washer was missing. Now my question is from what I've seen from the plan, there's one washer and 2 o-rings for the high speed needle and 2o-rings and NO washer for the low speed needle. Is that normal or do the plan is innacurate? Because on the order form below the plan the washers are sold in pack of 2. Any ideas?