Weber 32/36 K614 G63b Bogging Issues

[misosoup]

Hi everyone, first time posting. Just installed a new Weber 32/36 DFEV on my 1986 Mighty Max G63b Automatic. Also installed a new Carter electric fuel pump next to the gas tank. Truck will start up okay, but once I gas the throttle, the carb will backfire. Once I put it in gear, truck will bog/ die out when pressing the gas. Max speed uphill is about 5mph. When I pulled the new spark plugs they are covered in soot. First time working on a carb. I've attached a link with pics and vids below. Thanks

https://imgur.com/a/weber-32-36-dfev-bogging-46ytniY











https://imgur.com/t1WUI8a

https://imgur.com/b70319i

[xboxrox]

Hello misosoup

My truck (AFAIK & IMHO) is often experiencing near vapor lock conditions AND/OR in combination with perhaps the mechanical fuel pump is weak I will be installing a new oem fuel pump soon...

Also will be switching to NON Ethanol gas from MCBH Kaneohe marina

Edit: make sure the IN - TANK filter is clean my photo albums have pics about it ~ are you using more than the one fuel filter by the carb ?

Does Oahu now have two white 1986 Dodge Ram50s ?

[SubGothius]

Backfire is odd if the valve and ignition timing were good before and weren't touched. Just read in this other thread that jet valve malfunction can cause backfire and loss of power:

http://www.mightyram50.net/vbulletin...ll=1#post86167

The Weber conversion doesn't engage the jet valves at all, so you can try temporarily disabling them by removing their lash adjustment screws from the rocker arms under the valve cover.

That said, this may not help if any jet valve(s) got damaged. Look up "jet valve eliminator" for a kit of plugs to replace your jet valves; they just unscrew from the head like spark plugs, tho' you need to remove the rocker assembly to get at them. You'll also need a deep 14mm socket.

Been meaning to do that job myself, have read that the easiest way to remove the rocker ass'y is to remove the cam sprocket first. There's a hook provided to hang it on, so you won't lose cam/valve timing or have to mess with the timing chain. Keep track of which cam caps went where, so you can return them to their original positions on reassembly.

[misosoup]

Hello misosoup

My truck (AFAIK & IMHO) is often experiencing near vapor lock conditions AND/OR in combination with perhaps the mechanical fuel pump is weak I will be installing a new oem fuel pump soon...

Also will be switching to NON Ethanol gas from MCBH Kaneohe marina

Edit: make sure the IN - TANK filter is clean my photo albums have pics about it ~ are you using more than the one fuel filter by the carb ?

Does Oahu now have two white 1986 Dodge Ram50s ?

Hey xboxrox,
I have a carter electric pump right outside the gas tank. I haven't replaced the filter inside the tank though. I just picked up this 86 Mighty Max locally a few weeks ago! New to me work truck.

[misosoup]

Backfire is odd if the valve and ignition timing were good before and weren't touched. Just read in this other thread that jet valve malfunction can cause backfire and loss of power:

http://www.mightyram50.net/vbulletin...ll=1#post86167

The Weber conversion doesn't engage the jet valves at all, so you can try temporarily disabling them by removing their lash adjustment screws from the rocker arms under the valve cover.

That said, this may not help if any jet valve(s) got damaged. Look up "jet valve eliminator" for a kit of plugs to replace your jet valves; they just unscrew from the head like spark plugs, tho' you need to remove the rocker assembly to get at them. You'll also need a deep 14mm socket.

Been meaning to do that job myself, have read that the easiest way to remove the rocker ass'y is to remove the cam sprocket first. There's a hook provided to hang it on, so you won't lose cam/valve timing or have to mess with the timing chain. Keep track of which cam caps went where, so you can return them to their original positions on reassembly.

Hey SubGothius,
That will be my next project! I will be ordering those jet valve eliminator kits shortly. We'll see how that goes.

[misosoup]

Post update 04/02/25
Took apart the carb to check my jet sizes
Weber 32/36 DFEV
Primary Air Corrector: 165
Secondary Air Corrector: 160
Primary Main Jet: 137
Secondary Main Jet: 140
Primary Idle Jet: 65
Secondary Idle Jet: 50

[xboxrox]

miso & sub & camoit & ya'll

SUCCESS TRUCK RUNNING MUCH MUCH BETTER (here is what was done today):
1) Installed a new Mitsubishi mechanical fuel pump
2) Modified my new 5 gal gas can into an old style can easy pouring now
3) Put 3.5 gal NON Ethanol gas into the truck (purchased from MCBH Kaneohe Boat Marina)

NOTE: Future plan to cover engine compartment fuel lines & fuel filter with Heat Sheathing ~ maybe when all the (E10) ethanol is eventually burned the gas vapors will stop entering the fuel filter & into the Mikuni carb (the flow is 50/50 gas liquid & gas vapors)

[camoit]

The system should have a vapor separation can. It should have 3 lines off if it. One to the carb. One to the fuel pump and one to the tank. At least the first generation had that. Or you can go electric and run an external bypass regulator that recirculates back to the tank. I used a Tee with an orifice to control pressure.

on the Jet valves. They were designed to swirl the mix as it comes in. But since they are small they will glow hot and cause backfires or they will burn and crack causing low vacuum. Or they will fall off and bang around inside. But the head will crack between the jut and intake.

[xboxrox]

https://www.forbbodiesonly.com/mopar...l-pump.142238/

WIX PART #s and much vapor separator info at the link

[misosoup]

Hey Camoit,
Thanks for the info. Once my valve gasket comes in, I will start on the jet valve eliminator. I deleted the vapor cannister when I installed a Carter electric pump. I'm going to try and install the fuel filter with vapor separator and see how that goes. Also have a jet kit coming in tomorrow as well. Finger's crossed

[SubGothius]

There was a bit of confusion on that thread, conflating vapor separators with return-line provisions. The fuel filter with the third, smaller hose barb would be a return-line solution, tho' I suppose it could kinda work as a separator if the third barb is oriented to the highest point on the filter. Since you already have a quality filter, you could just get a tee with one smaller barb (1/4" IIRC) and connect that to your stock fuel-return pipe.

The idea there is to keep fuel constantly moving thru the lines at all times even when fuel delivery is slow, such as when the carb needle valve is closed or mostly so, which can happen at idle or sometimes at low-RPM cruise. Then fuel is never sitting still in the lines where it can soak up heat and boil into vapor, causing vapor lock.

There's a good wiki article explaining it in detail:

https://en.wikipedia.org/wiki/Vapor_lock

All that said, I'm not sure vapor lock is your issue, as I did the Weber 32/36 conversion and eliminated/capped my return line, and AFAICT have never had an issue with vapor lock even here in Tucson where summer temps get well into the 100s.

[xboxrox]

Check List:
1) carburetor is in good condition, clean & properly ajusted (especially float)
2) Fuel pressure & flow (gph) checked and sat within specs
3) Ignition system checked & sat (no weak coil bad wires etc)
4) Ignition timing initial vacuum cetrifugal all checked sat @ proper idle RPM
5) Cylinder compression tested & sat (these engines have weak cyl heads prone to cracks etc)
6) No air or vacuum leaks of intake or exhaust system
7) Fuel tank drained of old fuel & in tank fuel filter inspected & sat
8) Add good clean FRESH gasoline
9) Engine should run ok

My trucks main problem was EXTRA SUPER ROTTEN YELLOW COLORED CRAP BAD ANCIENT OLD WATER & GUNK CONTAMINATED FUEL & WEAK FUEL PUMP it ran bad until those two items got fixed... I don't experience actual vapor lock but I notice the carb is receiving about 50/50 gas vapor bubbles & liquid gas...

Good Luck Fixing misosoup

[xboxrox]

There was a bit of confusion on that thread, conflating vapor separators with return-line provisions. The fuel filter with the third, smaller hose barb would be a return-line solution, tho' I suppose it could kinda work as a separator if the third barb is oriented to the highest point on the filter. Since you already have a quality filter, you could just get a tee with one smaller barb (1/4" IIRC) and connect that to your stock fuel-return pipe.

The idea there is to keep fuel constantly moving thru the lines at all times even when fuel delivery is slow, such as when the carb needle valve is closed or mostly so, which can happen at idle or sometimes at low-RPM cruise. Then fuel is never sitting still in the lines where it can soak up heat and boil into vapor, causing vapor lock.

There's a good wiki article explaining it in detail:

https://en.wikipedia.org/wiki/Vapor_lock

All that said, I'm not sure vapor lock is your issue, as I did the Weber 32/36 conversion and eliminated/capped my return line, and AFAICT have never had an issue with vapor lock even here in Tucson where summer temps get well into the 100s.

SubGothius you're right about confusion regarding those three connector fuel filters; they are intended to connect to the fuel return line and/or provide a way to install & use a return fuel line... A fuel return line prevents fuel from just staying under the hood in high temps during idle 'n slow moving traffic... I noticed the OEM fuel pump has two outlets one to carb & one (with a small orifice) to fuel return line via nipples on the carbs accelerator pump cover...

Long but interesting YouTube videos about vapor lock & Weber carb mentioned:
https://youtu.be/Gqwb6U8vQfA?feature=shared
https://youtu.be/Zo24KUDYzCs?feature=shared