Get MH with leak above tank home..

[fasteddie313]

What I have to figure out now is how to get it home, 40 miles.. The fuel tank is pouring gas out the top and down the sides when the pump runs so it's not that simple and I don't want to drop the tank there..

It's an 81 rambler with 454..

I figure I can bring an alternative fuel cell to put by the passengers feet to get it home with and stop power to the rear fuel pump while I'm at it to get it home.. And also bring a spare wheel/tire with me and a lug wrench, jack, stuff to change a tire if one blows on the way..

What do you think I should do about the fuel? What size and shape line goes to the front pump? It has an electric fuel pump up by the engine, sounds like a diaphragm pump, and a professionally looking installed switch "installed by the original owner" on the dash, looks nice, it runs this diaphragm sounding pump up by the engine..

Any ideas on the tank pump as far as witch relay or fuse to pull to stop it?
What does the fuel return line circuit on the thing look like? Can I get in front of the return circuit and just direct feed the carb somehow?

What should I do here? Any fuel circuit diagrams out there?

[Rickf1985]

The first thing you should do is become a full time member so you have access to all of the manuals in the members area. That would help you out a lot. You say it also has an electric pump up front? What about the stock mechanical pump on the motor? That is where the return line comes off of. You could pull the wires off of the oil pressure safety switch which is next to the regular oil pressure gauge sending unit bottom left of the engine. This "should" keep the pump from running since the relay will not get an oil pressure signal and will not close. This is assuming the PO did not wire around the safety switch. It sounds like he did a LOT of questionable things and a lot of the standard advice may not pertain. The relay on my Winnebago is on the left of the inside of the dogbox. I have no idea on a HR. If you can shut off the in tank pump you may be able to get it to run on the mechanical pump IF it is not pulling too much air through the leak. I doubt the electric pump front will do much. The intank pump is a rotary vane pump so you cam pull gas through it even if it is not running but if the leak is bad enough all you are going to pull is air. I was able to drive mine at 60 mph without the in tank pump and a blown out regulator, just shut off the pump to keep it from pressurizing the regulator.

[DaveVA78Chieftain]

1. Join the site and download the GM motorhome chassis book we have.  Has a complete section on the fuel circuit from 79 to 90.
2.  GM did not start installing an in-tank fuel pump until 1985 1/2.  A 1981 chassis (you said 81 rambler) would not have an in-tank electric pump (stock that is).  If you have an electric pump up front then it was added.  Who knows how it is wired.     Should have a regulator also.  What I suspect is happening is the electric pump is to big and excess fuel is being forced back to the tank via the return line on the original mechanical pump.   The return hose at the tank is old and cracked resulting in the fuel loss.  You may not even need the electric pump to run this to get it home.
Dave

[TripleJ]

Likely as posted above, the return line above the tank is leaking.

You will literally need to follow thte lines as best you can get to try and understand how your particular unit is set up, or how a PO messed it up while 'fixing' it.

This is another reason i preach against multiple fuel pumps.  N:( theres always a better way

[fasteddie313]

Ok I didn't know that there was no rear/in tank pump, the leak at the top of the tank made me think there was. The return line theory sounds good..

I was told the electric fuel pump was installed by the original owner to help it start after long periods of sitting. It is a nice switch on the dash that is even labeled nicely and looks well done/OEM..

He flipped the switch before starting, started right up, auto choke, shut the FP switch off, and it ran for 10 minutes or so very well and quiet except an exhaust leak. After that I was looking under it again and it had fuel down the side of the tank on the drivers side, wet about a foot wide all the way down, not a small leak..

I got the membership too..

[fasteddie313]

Here is the FP switch, just under to the right of the key with the red labeling under it..




I didn't mention how nice of shape the dash is in along with the rest of the same vinyl covered parts are great..

[Rickf1985]

Unless there is a pump in the tank then it would have to be coming from the return line since the main feed line would be in suction from a pump in the front and hence it would pull air in and not let gas out while running. It should not really be bypassing that much gas unless the line is broken off altogether. You could plug the return line at the pump and see if that stops the leak. That would get you home. The return line is there to return vapor to the tank and also to keep gas moving fast enough to try to prevent it from boiling in the lines. If it is not too hot you should be alright with the return blocked off.

[DaveVA78Chieftain]

Once Mark provides you with the access codes to the member area, select Chevy/GMC P30 section, then download the '79-'94 Chevy/GMC P-30 Chassis Service and Maintenance Manual manual.  Fuel info is pdf pages 134 through 154.
Then scroll down to 1981 and download Service, Component Overhaul, and Wiring manuals.

[M & J]

Congrats on being a member. Best decision you'll make next to getting an RV.

[lemortede]

Congrats on being a member. Best decision you'll make next to getting an RV.

THIS.

[TripleJ]

I do have to crank mine for 5-10 seconds, sometimes twice, after sitting for a week or more.  I like to think of it as priming the oil galleys so my cold starts aren't dry.  Some people pay big $$$ for oil priming setups, mine is automatic!

And I will take that ANY day over multiple pumps and all the new possible failure modes they bring.

[fasteddie313]

Thanks guys, as you said, and I went and had a chat with the OGs at the junkyard, I think the plan is to NOT use the electric pump and to block off the fuel return line where it comes off of the fuel pump. That combination should get it home safely, I hope..
They are also giving me a spare tire to take with me if I want but also say I won't need it..

[fasteddie313]

Clamping the return line just off the block pump with some small vice grips and cardboard jaw cushions did the trick nicely..