Installing Generator Fuel Lines to Main Tank

Glennman · February 09, 2020, 07:36:56 PM

I'm getting ready to install the fuel lines from the main tank to the Kubota diesel. I removed the approximately 2 1/2" plate off the tank that exposes a 1 1/2" hole in the tank. With having to install the suction and return lines, what fittings have you guys used to get both fittings installed in the plate (about 5/32" thick aluminum plate)? They will need to be installed next to each other taking up no more than 1 1/2". Plus there is the pickup tube.

I'm thinking minimally that rubber gas line hose could be installed with heavy grommets fitted in tightly, with a copper pickup line in the inside. Best case would be a couple of fittings that would mechanically sandwich the original plate with gaskets, and the pick up line would install on the inside, and the suction line from the generator would install on the outside of the fitting that sandwiches the plate, so that it could be disconnected without removing the pickup line from inside the tank.

Any suggestions? Thanks, Glennman

DoubleEagle · February 09, 2020, 08:23:29 PM

Those with MCI's can advise you best with the fuel hookup, on my Eagles there are extra fittings already on the tanks to use. My only advice would be to not forget to have the pickup tube for the generator several inches higher than the engine pickup so that the generator does not use up the fuel, preventing the main engine from going very far (in case you forget to fill up often enough, or the gauge is off).

Paul S · February 10, 2020, 07:49:31 AM

My conversion was done by executive coach, with the gen lines higher then the bus - I don't know if I can get in there to get photos but if I can I will.

richard5933 · February 10, 2020, 08:24:23 AM

Here's how Custom Coach tapped the generator lines from the main tank. They are on the side (end) of the tank, just next to the manufacturer's plaque.(Sorry for the rotated photo)

peterbylt · February 10, 2020, 08:29:21 PM

I just went through this with the 96A3, I assume your MC8 should be similar.

Gumpy Dog did a similar design, I modeled mine after his, see his for more information.

I removed the large vent on the upper left of the tank looking at it through the Fuel fill door.

I bought a roll of 5/16" stainless tubing from amazon, we then fabricated a stainless disk the same diameter as the vent and drilled holes for the pickup, return and vent tubes and the 5 screw holes.

I measured the tank and made the suction tube 5 inches shorter than what I determined was the length of the engine pickup so as not to run the engine out of fuel when running the generator.

Then bent the tubing to fit through the mounting puck, after several test fits my friend the expert welder, welded it all together and I installed it.

Although it is installed, I have yet to use it, Plumbing and wiring the generator is getting closer to the top of the list after the Airbags and radius rod bushings are done.

I was going to use more of the stainless tubing for the fuel lines to the generator, but the guy at the local Goodyear hose and fitting store persuaded me to use some armored flexible fuel line, I have not purchased it yet, but I think that is the way I will go.

Peter

Glennman · February 10, 2020, 09:39:32 PM

Peter, your install looks great (richard5933 looks good too) . I'm a little confused on what the 3rd line is for, but I see you have the shorter pickup tube so as not to run your main tank out of fuel, and the return line. I'll also be looking into the "armored flexible fuel line" as well. It all looks great. Thank you guys for all the great pictures and ideas! Glennman

buswarrior · February 11, 2020, 04:52:42 AM

An outboard motor fuel line priming bulb in the generator line is a mighty thing for ruling out/dealing with prime issues WHEN your generator starts having running problems.

Won't start, squeeze bulb, starts... you know exactly what is wrong, and can focus, or not, on finding where the air is getting in.

Most attempts at generator no-start diagnosis have a large chance of creating further self inflicted disablements in the prime file.

The bulb requires inspection and some periodic replacement, same as on your boat, but oh what a handy thing it is.

Happy coaching!
Buswarrior

peterbylt · February 11, 2020, 06:30:14 AM

Quote from: Glennman on February 10, 2020, 09:39:32 PM
Peter, your install looks great (richard5933 looks good too) . I'm a little confused on what the 3rd line is for, but I see you have the shorter pickup tube so as not to run your main tank out of fuel, and the return line. I'll also be looking into the "armored flexible fuel line" as well. It all looks great. Thank you guys for all the great pictures and ideas! Glennman

Glennman,

The third line is a fuel tank Vent (what this port originally was)

On other vehicles, I have had issue with vacuum lock due to no vent on the fuel tank.

Gumpy Dog told me he did not include a Fuel Tank Vent on his and never experienced an issue.

Peter

luvrbus · February 11, 2020, 06:37:48 AM

Pick and a return line is all you need and most Japan made generator engines have a electric fuel pump since they don't have their own fuel pump per say some have a manual pump on the block,3rd line is usually a bleeder line for system

Jim Blackwood · February 11, 2020, 08:34:05 AM

If you add an electric fuel pump, mounting it low and close to the tank is a good idea. They really aren't good at suction. As most generators do have a pump, it would be an extra and not needed most of the time unless you remove or relocate the built in pump. The squeeze bulb is a plus of course. Great for testing if the built in pump is up to the job.

Jim

luvrbus · February 11, 2020, 10:26:35 AM

I have never installed a new Kubota powered generator that had a pickup fuel pump,some came with electric pump in the kit and some didn.t they do have a injection pump but they will not pickup fuel unless it gravity feed, the electric pumps do a good job picking up fuel from suction that is why they are used as primping pumps.This electric pump pulls fuel from 22 ft away from the tank and the standard mounting place for the Kubota engines in generators

Jim Blackwood · February 11, 2020, 12:06:40 PM

Quote from: luvrbus on February 11, 2020, 10:26:35 AM
... the electric pumps do a good job picking up fuel from suction that is why they are used as primping pumps

I guess it's all relative. Compared to an engine driven fuel pump or a squeeze bulb electrics are poor at lifting fuel, which is why they are almost always placed low and close to the tank. Inside the tank if possible. They really are much better at pushing the fuel than pulling it. Of course, compared to no pump they are great!

Jim