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Kohler 7.5KW Marine genset with L654 engine, convert to electric fuel pump

stevegnh

Registered
My generator is a 1989 7.5R marine generator with the L654 engine. Spec is 106275-A and the serial number is 223353. The previous owner added an electric fuel pump onto it, but I don't believe it was done correctly.

First, I believe the pump used may be putting out too high of a pressure. I'm reading that this engine and carb likes around 1.5psi. The Facet PosiFlo pump used is for 1.5-4psi, so not sure how it regulates itself to be on the lower end. I'm thinking it doesn't.

Second, while I find this pump is solid state, I don't believe it is ignition protected for use in a boat's engine compartment.

And third, for wiring it up, the installer spliced into the auto choke wire, so I'm not sure if the pump is even getting 12v. I'll have to check that. It must though, as the generator will run, but I'm told by someone the positive of the fuel pump should be hooked to pin 70 in the control panel.

This has all been done, with original mechanical fuel pump still in place. The problem is the carb leaks gas. I'm not sure if it's a carb issue (bad bowl, gasket), torn diaphragm in the old pump, or too much pressure, or a combination of all of them. I also was told the fuel line to the carb should be no more than 1/4 to reduce chances of overfilling. I'm pretty sure the hose used is 5/16" ID.

So my plan is to remove the carb, clean it and rebuild it. I also want to completely remove the old mechanical fuel pump. I still, even with the electric fuel pump, have to use the prime level to fill the mechanical pump with gas, so what's the point of the electric pump??

So my questions are what really needs to be done to delete the mechanical pump, is the fuel hose size ok, and what would the recommended electrical fuel pump be for a boat, with the right pressure, and how should it be wired.

Thanks for any help and tips.

Here's a pic of the setup, so you can see the wiring splice and how the electric pump gas line just goes into the old pump's body.
 

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stevegnh

Registered
To add too, the reason why I don't want the mechanical pump in there at all is so I don't need to have to prime it with the lever. To do this I have to remove the engine hatch and climb down there to prime it, then climb out and start it up.
 

SalmonBoy

Subscriber
Last Subscription Date
06/16/2020
Have you seen the actual Kohler GM75606 I think it is, electric conversion? I’m actually headed to my boat now to install it on my L654 now. I attached the instructions here. Notice it says to remove the brass line from the collection tank and plug that hole on the collection tank. I think I see yours still connected which may be causing your prime issue. This kit actually came with a gasket and bracket to close off where the mechanical was and mount the electric pump. My question to you would be that this kit tells me to splice into the fuel valve wires..if that becomes an issue, where is this pin 70 located. I’ll let you know how it works.
 

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stevegnh

Registered
Have you seen the actual Kohler GM75606 I think it is, electric conversion? I’m actually headed to my boat now to install it on my L654 now. I attached the instructions here. Notice it says to remove the brass line from the collection tank and plug that hole on the collection tank. I think I see yours still connected which may be causing your prime issue. This kit actually came with a gasket and bracket to close off where the mechanical was and mount the electric pump. My question to you would be that this kit tells me to splice into the fuel valve wires..if that becomes an issue, where is this pin 70 located. I’ll let you know how it works.
I installed this on my genset, this exact kit. I did remove the collection tank line and plugged it (where the mechanical fuel pump connected).

As for fuel valve splicing for the power for the fuel pump, not all variations of this genset have the fuel valve. Mine does not. I connected it to pin 70 in the control panel on the end of the genset. I have a relay model, and pin 70 was clearly labelled when I opened it up, both on the circuit board as well as a lable on the wire. My genset starts very easy. I crank it for about 3 seconds to get fuel flowing to carb, then off and on, and it fires right up, every time. It just hunts for the first 45 seconds or so. And then the issues I'm trying to solve in this thread when I put a load on it.

---------- Post added at 11:33:28 AM ---------- Previous post was at 11:30:19 AM ----------

My last sentence of my last post likely confused things too. I have another thread going where I'm trying to solve the genset hunting under load. I mixed up threads, thinking your reply was in that thread, vs this one. I did already finish the conversion, and the pic above was before I did the install, which is why you don't see the plug. I will post a few pictures to help you too, showing the wiring and my completed job.
 

stevegnh

Registered
Ok, here's some pics of the wiring, and the finished product. Again, my genset is a relay model, not solid state, so yours may vary. But in the pics, the brown wire you can see connected to pin 70, then in the second wiring pic, the heavy red wire you see is the positive to the fuel pump, just connected on the same terminal as pin 70.

Good luck.
 

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