WOT no go!

[Nate3172]

Re: WOT no go!

It is this one.

 

[bjhc100]

Re: WOT no go!

Nate, did you do away with the original pump, disconnect and/or leave it in place and add the elecric pump up-stream. I ask this because I wonder if the engine could be pull started with a dead battery without having the original pump and squeeze bulb in place to aid the starting. Thanks Harley

 

[Nate3172]

Re: WOT no go!

I by-passed the mechanical and just left it in place on the engine. I left the primer bulb in the system though for a back-up just in case. I have not had to use it as of yet, but just a little insurance. The electric "pusher" pumps are not designed to really "suck" fuel, but rather "push" fuel. So, with that said, if you lose too much of the prime to the pump from the tank, it can have a hard time drawing that fuel up from the tank. That was one of the main reasons I left the primer bulb in the system so that just in case that happened I would be able to prime the fuel up to the pump. Like I said though, I haven't had to use it yet. Well, except when I initially installed it.

 

[MercFan]

Re: WOT no go!

I use one of these pumps on my 1970 IL6 Merc. They really don't deliver any pressure. Made specifically for carb applications. Mine is a diaphram pump. It's simply a diaphram with a spring and a solinoid on the one side. The solinoid pulls the diaphram and thus sucks fuel from the tank. The spring then pushes the diaphram in the opposite direction and that gives the fuel delivery. When the floats bowls are full and the needle and seat are closed the pressure is equal to the tiny spring under the diaphram. It really isn't a lot. So the pump can only pump if there is a need for it to pump. Else it just sits mid stroke, doesn't use any power or anything.

It charges up my fuel line faster than I could do it with the primer bulb. I also don't have to worry about air leaks in the fuel pipe, since everything is under positive pressure. So I can simple see fuel dripping if I have a leak instead of trying to find a vacuum air leak.

I wired my pump to the ignition as someone asked. It only pumps when the key is swithed "on". I saw in the specs that the pump draws something like 0.1 amps or something. So very little, and only for half it's cycle.

On a side not. Just to confirm the pressure was the same as the mechanical pumps on the engine I did check the fuel levels in the floats bowls bot before and after installation of the pump.

I installed the pump only a couple of inches from my tank because these pumps arn't great suckers. And the further you move the pump from the tank the less you have the "no vacuum" advantage.

Here's my pump, the 133010 or 133000, can't remember which
http://www.gowerlee.dircon.co.uk/HUCO.html

 

[CharlieB]

Re: WOT no go!

If you install an electric pump, ALWAYS bypass the OEM pump.

Outboards used the vacuum operated pump for 2 reasons, cost savings, and when it fails the fuel loss is sucked inside the engine, no fuel spill to the outside, no fire risks. This has the added benefit of adding fuel to a cyl, fouling the plug and the operator should notice the power loss, get it repair before damage occurs.

An electric pump pressurizing the original system has the potential of flooding the cyl providing vacuum to the pump, washing down the rings and damaging the cyl.

I only advocate the electric pump for testing and diagnosing fuel problems.

 

[Nate3172]

Re: WOT no go!

It only has that potential if you leave the mechanical hooked up in the system. Why would you, though? It would serve no purpose. Fuel delivery is not rocket science. If you choose the correct fuel pump for the type of system that you are delivering fuel to, than there will not be a problem. If you want to simplify the fuel delivery system and delete the procedure of having to pump the primer bulb, than by all means, install an electric pump. If not, than don't. I have done numerous engines and have never had a problem.