Time to stop the flood!

[Rambini50Ra]

My '89 4x4 SB with G54B has had a carb from JT outfitters kit #61434 on it since '06 202K, now has 235K miles. Always has flooded after shutdown. Has fuel psi reg set to 3psi ? Started looking for carb and emailed Red line and another legit supplier but lost all mail in a hack.
I welcome all help and advice.
Thanks everyone, Lunny

[geezer101]

Hi. My money is on the regulator being faulty or it doing something like retaining fuel pressure after shutdown and bleeding the remaining fuel pressure into the carb. It is a bad idea to try to run a regulator on the factory mechanical fuel pump anyway. I would take the regulator out, disconnect the lines to the mechanical fuel pump and run an electric HVLP fuel pump instead. You'll need a fuel pump, a 4/5 pin relay and a fuse to protect the system. MY budget pick is a Carbole 42S fuel pump - can pick them up on ebay and is about half the price of the Mr Gasket 42S pump (identical pump - different sticker...) I have used a Carter rotary vane pump and it sucked. It was expensive, noisy and it chewed it's insides out in a relatively short time.

[Rambini50Ra]

Geezer101, you don't suspect my Weber knock-off may have any other internal issues? If I put in an electric pump can it be in engine compartment or better in-line back by tank?

[geezer101]

One problem with the Weber clones are the internal metering galleries. They can't be altered to run the same way a legit Weber does so they suffer from lean/rich running issues. Some of the knock offs have roasted the tops off pistons. The ideal way to set up a Weber is having the fuel pump as close to the fuel tank as possible as these pumps won't like trying to prime a carb when the fuel pick up is 5 feet away (it makes the pumps work really hard) Have a filter between the pump and tank to protect the pump. Make sure the pump is in a location where it's not going to get hammered by road debris. Check the Weber install threads on the site as a guide and you can't go wrong.

[Rambini50Ra]

Thank you Geezer. So I think my return line on mech. pump is plugged off. I read a thread that said something similar and said the return should've been hooked up to the replacement weber. True or false?
My pump has two barbs on the output side, one is blocked off, I assume that was to the return maybe through original carb...now I gotta look at it again. Memory is thrashed.

[SubGothius]

Webers don't care about a return fuel line; they should work fine with or without, tho' having a return line can help prevent vapor lock and stirs up fuel in the tank to help prevent debris from clogging the fuel pickup. You'd add a tee for the return line before any fuel pressure regulator you may have.

Some stock Mikuni carbs had two fuel inlets, so that's what the two outlet barbs on the stock mech pump are for, effectively a built-in tee. Webers only need one fuel supply, so you can either cap off the second outlet barb on the pump or just use it as a tee to the return line.

[Rambini50Ra]

So, the original Mikuni carb had a return outlet that was ported to the tank? A idea if I will gain anything if I connect my extra pump outlet to the return line to tank? That would ensure I wouldn't have trapped pressure against my float needle. I much appreciate the advice and suggestions.
Thank you all.

[geezer101]

The updated fuel pumps have 2 outlet barbs - one goes to the main inlet to the fuel bowl on the Mikuni (primary) and the second goes to the accelerator enrichment pump that then passes back out to the return fuel line. The early ones had line in and one out - they were rebuildable and required a recirculation cannister to split fuel delivery. There is also the vapour return line as SubG has stated - this line can NOT be blocked off. Capping this line off will cause vapour lock and the condition magnifies in hot weather conditions (enough to starve the engine out of fuel - releasing the fuel cap relieves the pressure build up) I can't guarantee that hooking up the secondary fuel line to the tank return will relieve fuel pressure but give it a try. The other option is find a fuel filter with 2 outlets and connect the return to it. I found the fuel filters and left a link a while back but I have no idea where...

[Rambini50Ra]

The updated fuel pumps have 2 outlet barbs - one goes to the main inlet to the fuel bowl on the Mikuni (primary) and the second goes to the accelerator enrichment pump that then passes back out to the return fuel line. The early ones had line in and one out - they were rebuildable and required a recirculation cannister to split fuel delivery. There is also the vapour return line as SubG has stated - this line can NOT be blocked off. Capping this line off will cause vapour lock and the condition magnifies in hot weather conditions (enough to starve the engine out of fuel - releasing the fuel cap relieves the pressure build up) I can't guarantee that hooking up the secondary fuel line to the tank return will relieve fuel pressure but give it a try. The other option is find a fuel filter with 2 outlets and connect the return to it. I found the fuel filters and left a link a while back but I have no idea where...

Geezer101, reattached the return line to my 2nd output Barb and Ta-Da!
Presto no flood-O! At least it appears to have removed the pedal down, black smoke routine for now. I feel foolish not learning this years ago but hadn't asked the question to the right people. Thanks everybody for the knowledge. It's greatly appreciated.

[Rambini50Ra]

Webers don't care about a return fuel line; they should work fine with or without, tho' having a return line can help prevent vapor lock and stirs up fuel in the tank to help prevent debris from clogging the fuel pickup. You'd add a tee for the return line before any fuel pressure regulator you may have.

Some stock Mikuni carbs had two fuel inlets, so that's what the two outlet barbs on the stock mech pump are for, effectively a built-in tee. Webers only need one fuel supply, so you can either cap off the second outlet barb on the pump or just use it as a tee to the return line.

Thank you SubGothius. I appreciate the help.
It's good to know people in the know!

[geezer101]

Most excellent result :beavisbutthead: