VRO Fuel Pump replacement

[NilsRadtke]

Hy there,
I replaced my VRO fuelpump because it is broken. I (will) run the engine (Evinrude 1987 70HP) with a separate electical fuelpump (it was running once - fine). My question is about the 4 hoses of the original pump. The one on top ist the fuel/oil-output to the carbs. Then there are 2 inputs for oil and fuel each (I know which of them). The last one is the one I am interested in. What is it for? It seems to be connected with the cylinder and a hose coming from the cover of the carburetors. Is it to remove superfluous fuel into the cylinder? With my new pump I just connected the input and output hose, but I don't know whether this one hose is important?!
Thanks a lot.

 

[Silvertip]

Re: VRO Fuel Pump replacement

Please, for your own safety, rethink using an electric fuel pump on your engine. Yes -- EFI/DFI outboards and EFI I/Os run electric pumps. The problem with adding one to a carbureted outboard is that there is no way to shut it off in the event of an emergency. EFI/DFI systems rely on oil pressure or the ECU to kill the pump if the engine quits. On your engine there is not convenient way to do that without some additional mods. Should a float stick you will flood the engine with fuel. Should you have a fuel leak you will flood the engine with fuel and heaven forbid if you have a fire the fuel pump will continue to run and feed the fire. The engine was designed to run without an electric pump. Fix it correctly. You can even install a non-oil injection fuel pump with no other mods. The four lines on a vro pump are oil in, fuel in, oil/fuel out, and pulse from the crankcase.

 

[tx1961whaler]

Re: VRO Fuel Pump replacement

I second Silvertip. It's not safe without a safety shut-off. I have used electrics on inboards, but they always had a shut-off from the oil pressure sensor.

 

[NilsRadtke]

Re: VRO Fuel Pump replacement

@ silvertip: Thanks.
I installed two different security-options to shut down the pump immediately and the pump isn't installed in the motor. There should not be a problem at all.
Thanks for the second part of your answer-but I still have a question. I don't know exactely what the "pulse from the crankcase" means. With other words: is it possible to run the engine in combination with the new fuelpump without regard to the fourth line? Is it okay to "close" this line or do I (the engine) need it definitively?
Thanks

 

[Dhadley]

Re: VRO Fuel Pump replacement

I don't think you're understanig what he's saying. It doesn't matter where the pump is, it can cause a carb to overflow from anywhere. You really should re-think what you're about to do. There's a reason the OE manufacturers didn't do it.

The pulse line is what operated the mechanical pump.

 

[NilsRadtke]

Re: VRO Fuel Pump replacement

@ Dahdley:
Thanks again for a good and fast answer. You are right when you said that I didn't understand silvertip at all. Now I know what might be a problem and I think I allready solved this problem because I was confronted with it. I checked how the pump and the carbs work together while running the engine with the cover opend. Thereby I reduced the power of the pump to some different levels which I can change with a shifter that there is always the right amount of fuel pumped to the carbs.
But with regard to all your answers I will think about it all once.
And thanks to you for the second part which helps me a lot.
Best whishes, Nils

 

[kenmyfam]

Re: VRO Fuel Pump replacement

Personally I would replace it with a tried and trusted solution.
#1. New oil mixing pump
#2. New premix pump and mix the 2 stroke oil with your gas.

#1 is more expensive but a little quicker to install
#2 is way cheaper, a little more trouble to fit and a little more trouble as you have to mix the fuel with the oil.

Sounds like a potential disaster waiting to happen with the electric pump.
I have a thread on changing from VRO to pre-mix in this section. Do a search for "now a pre-mixer" and you should find it.