1981 Pickup 4 X 4 New Owner (1 Viewer)

[t6dpilot]

Thought I would bump this to the top to get the opinions from the participants of this thread. I did start one on this subject separately, so a bit redundant. I spent the summer driving the truck and doing a few things like fully buffing the paint and changing the gear oil in the front and rear differentials. Just wanted to put some miles on it post suspension and brake work. Ran great all summer and brought it home one of the last times before putting it to bed for the season. Went to take it back to the hanger and it would not start. That's odd... Tried again with a bit more pumping, no go. Really odd... On the fourth try after numerous cranks, she fired up and I thought well, maybe I just flooded it. Ran great on the 20 minute run to the hanger and parked it.

Weather was good a couple weeks later, so I decided to drive it. No start. No matter how I tried, it would not fire. OK time to go through the typical things - electric, fuel, air.

1. Check spark at plug 1, yes,
2. Check fuel filter, looks unobstructed and full of fuel,
3. Tried starting fluid into carb and the truck fires right up,
4. Change fuel pump to Kyosan,
5. Check choke diaphragm, feels pliable, pull hose, press mechanism in, attach hose. Holds position, so no leaks there,
6. Check fuel cut solenoid and it clicks when 12V is applied,
7. Check fuel flow at carb, it has good flow,
8. Check float bowl level, looks empty. Hmmm,
9. Removed the banjo fitting at float bowl and it is clear,
10. Blow compressed air in open passage leading to needle seat and valve.

Tried fuel again and it is getting to the carb, but not into the float bowl. I looked at the needle seat and the screen looks clean and unobstructed from the inlet. I am at a loss and do not want to disassemble the carb. What is weird is that the truck ran beautiful before the hard start issue and after. Now nothing. Very strange. Any ideas? Wish I could get to the float bowl without having to disassemble the accelerator linkage. That appears to really complicate getting the top off instead of the 5 screws and a few lines.

 

[aztoyman]

So if you disconnect the fuel line AT the carb and cranked the engine over, will fuel come out of the open line?

You should get pulses of fuel from your mechanical pump. If the needle is stuck, it will prevent a low pressure mechanical pump's flow into the fuel bowl on most carbs. Are you sure the fuel passage to the needle and seat is open?

Sorry, I don't know anything about your particular carb so I'm having trouble visualizing this. I'll try to look one up.

 

[aztoyman]

I looked at some pics online. I see the banjo fitting and I'm guessing there is a screen behind that in the casting which you said is clear. The small holes on the banjo bolt are open I'm assuming? And then it looks like it would flow to the needle and seat?

I see on the pics that there is what looks like a drain plug for the fuel bowl. Below the sight glass? Any way to pull that plug and shoot some carb cleaner in the bowl? Assuming I'm looking at a carb like you have anyway. Is there a bowl vent that could be plugged?

Definitely looks like a complicated carburetor so I see why you don't want to pull it apart when it runs well intermittently.

 

[gnob]

pretty sure the diagonal tube coming into the venturi area is the bowl vent/overflow. you could potentially put fuel in that hole and see if you can fill the bowl.
like i mentioned before, if you have fuel to the carb and nothing in the bowl, there's basically only one thing it can be.
it's really not that big of deal to pull the top off to inspect the float and jet.

 

[thetoyotaman]

Some of these 22r carbs at this age are not holding fuel in the bowl before leaking out into the intake manifold. So, your engine is flooded before you try to start it. You can try holding accelerator down on first crank to clear it out but ultimately this problem can fuel wash your rings and cause engine damage. Carb needs repair.

 

[t6dpilot]

Guys, thanks for taking the time to respond and the brain power.

@aztoyman Yes, I get fuel to the area where the needle seat and screen are. The banjo fitting and bolt are all clear. I assume that the screen is attached to the needle seat by looking at the Asian carb diagram. Screen looks clean and I am baffled that if the float is hanging down, why would the needle be stuck to the seat? The float should pull the needle away from the seat and let fuel in. Unless it got stuck and pulled off the float arm. Figured a couple shots of compressed air would free it if it was. Also, as a reminder from earlier in the thread, I do have an electric fuel pump in the system (not sure why) that provides good consistent pressure.

@gnob thanks for checking in here and your help on my other thread. Totally agree with your previous suggestions. That is what prompted me to watch a bunch of stuff on carb troubleshooting and the float bowl situation in particular. Which prompted me to attempt to take the top of the carb off. Was super stoked to get inside and pulled all the lines and the 5 screws holding the top on and DOH!, the accelerator linkage needs to be removed. Looks complicated and didn't want to go down that rabbit hole yet, so put it back together. Do you have a way to get the linkage off the top of the carb so I can easily pull that off?

Thanks @thetoyotaman. By saying the carb needs repair are you recommending a rebuild kit and pulling the carb for a full rebuild? Probably a good idea, but darn it the truck ran great. Who sells the best rebuild kit?

What baffles me is this is a "digital" failure meaning that truck ran great and then nothing. Smacks of an electrical issue, but that is not it. Or a failed fuel pump, but that isn't it either. I appreciate all the suggestions. I would think a fuel issue would manifest itself gradually. I have experienced that before - partially blocked filter, fouled jets, low pressure.

 

[gnob]

the last carb i dicked with was years ago and I don't think i full disassembled the linkage to access the float and jet.
it seems like i was able to only partially disassemble the linkage to free it up enough to get the cover off

 

[thetoyotaman]

Sometimes the carb works perfectly fine but the fuel bowl leaks down. I haven't had a chance to work on this project yet but I'd like to learn why this becomes common on the 22r carb as it ages. Most likely the power valve is leaking. So, a carb rebuild may not actually fix this particular problem.

Have you made sure the electric fuel pump is not overpowering the carb with too high of pressure? IIRC, Webers need a about 1.5-3 psi and Aisin about 4-5 or slightly more???

The USA made carb kits like Walker seem to be pretty decent quality and have more flexible diaphragms than OE.

 

[t6dpilot]

I don't think the fuel pump is overpowering the carb, but I only state that because the little Facet pump looks to have been on the truck for years. And I drove it all summer without issue. I think I have a fuel pressure gauge that I can install to check it. Or I can just try to bypass it.

There appears to be a blockage with respect to fuel entering the carb/float bowl. I watched a couple more videos on pulling it apart and removing the top half may not be as bad as I initially thought. I'll give it another look see and decide what to do from there. I may try taking the window off and putting a little fuel in the bowl to see what happens to it and if I can start it.

 

[thetoyotaman]

If you take the float glass off, the oring will not be reusable as it's already compressed and it's a square cut o-ring. A traditional ring won't tighten correctly and break the glass.

The air horn (top part of the carb) is removable on vehicle and typically the gasket is reusable if cleaned with brake clean prior to reinstall. The screws just need to be snug, not overtightened. There's some linkages on the backside of the carb that have tiny clips holding that are easy to lose upon removal. When you pull it up following that you'll see the long needle that goes into the power valve. Make sure that goes back in the correct hole to avoid damage upon reassembly. Also make sure the pin that holds the float doesn't fall out upon reassembly.

If yours still has the screen on the needle valve seat when you unscrew it from the air horn, be really careful with it as it has a plastic ring holding it on potentially and most rebuilders seem to just throw those away. I like to keep it stock and reuse.

 

[t6dpilot]

Thanks for the tips. I will not remove the glass cover based on your information. I might try applying suction from a vacuum to the inlet port on the carb to see if any debris comes out. Then try some carb cleaner through the same port. I studied the linkage mechanism on the back of the carb to see how to remove it. Looks very complex and ripe for screw ups. I do not want to nor do I think it is necessary to remove the whole carb. I am about done with this and give it to a professional. Damn, I'm frustrated and baffled.

 

[aztoyman]

We're all baffled as well and looking forward to the answer. Unfortunately you get the frustration. Definitely a weird one.

 

[thetoyotaman]

Sometimes you can see the float position inside the glass whether it's up or down. If it was me, I'd start with removing the fuel inlet hose when it's sat overnight and see if you can fill the bowl with brake or carburetor cleaner. Won't hurt anything.

The problem with a professional is finding someone in today's EFI world that has ever worked on a carburetor....

 

[t6dpilot]

OK guys, success! The truck runs great again. Starts quick and runs smooth. The solution turned out to be very simple as I suspected. I looked and looked at it today and talked through everything I have done. It did not make sense that the float bowl was not getting fuel. So I rigged up the Shop Vac with a small hose and gently applied a vacuum to the fuel inlet area. Thinking I might remove debris blocking the inlet. Still wasn't convinced that did anything, so I tapped on the top of the needle seat chamber with a plastic hammer. I don't know, did that do anything? Not sure, so I fired up the air compressor and rigged the same vacuum hose (small diameter) to see if I could better pressurize the chamber. It worked great, but I could feel blow back from the carb inlet area, so thought it was not successful.

I figured I have done what I could do and reconnected the fuel line to see if it would start. Turned on the ignition and checked the fuel bowl window. Fuel is flowing! Hot damn! Tried starting it and it fired within a second and was running great. It appears that the needle was stuck in the seat. Weird... Wow, what a relief, so frustrating. I really appreciate everyone's help and advice to get over this hurdle. Thank you! It is guys like you all that help us get through challenging projects no matter what the car/truck forum.

Now, back to the refurbishing of the truck. I'll report back with other progress. Windshield seal replacement is next and an engine compartment cleaning shortly after.

 

[t6dpilot]

I probably should have taken photos of my progress, but was too wrapped up into it to think about that. I may do that later to show what I did to solve the issue.

 

[thetoyotaman]

Don't know what kind of fuel you run, but it sounds like an ethanol fuel problem. Ethanol turns into a gummy cotton candy type substance in carburetors. Problem tends to get amplified anytime a carb sits.

 

[t6dpilot]

I run premium fuel in the truck. It just seems to run better with it. Also, before I had this problem, I filled the tank and put Seafood in it for storage during the winter.

 

[pappy]

... I filled the tank and put Seafood in it ...

 

[thetoyotaman]

Probably not Seafood.....

In all reality, if a pump shares a nozzle between ethanol and non ethanol the non ethanol will always be contaminated at some level.

 

[t6dpilot]

Seafood... Now that is some funny autocorrect. Seafoam was put in the tank.

@thetoyotaman I'll bet your suggestion of spraying carb cleaner or brake clean in that same port would have also done the trick. Well, at least I know what to be on the lookout for in the future. Sure is nice to get a good running truck back.