How to prime a Weber?

[Yellow Jacket]

PO put a Weber 38 on my 40. I plan to go back to OEM and I'm slowing collecting the parts. Until then I have this question:

How can I prime the carb or get fuel in the fuel bowl after the truck has been sitting for a while? Apparently Webers are bad about the fuel in the bowl evaporating in a short time period. My rig can sit for weeks as my slow a$$ works some little project.

It takes a long while for the engine to fire up after sitting just because the fuel has to get pulled up to the carb from the tank. I hate to think of the damage I'm doing to the cylinder walls as it cranks over for 20+ seconds before firing up.

What is the best way to get fuel in the carb by hand before I turn the key? Also if not obvious by now, I know nothing about carbs, but my internet research on this question has come up empty. I see some have added an electrical fuel pump to help with this issue, but I really dont want to invest in that since I'm going to go back to the Aisin eventually.

Thanks

 

[handcannon]

Use a hand pump oiler with gas in it. Pull the filter off the top and squirt a little bit in the carb just before starting. A bit of experimenting with how much is just enough may be needed. Put the filter back on before trying to start though as you might get a pop back through the carb if you get too much gas in there. The filter will contain anything that comes back through the carb. It is possible to get way too much raw fuel in there if you are not careful and get a bit of fire in the throat of the carb. If so, IMMEDIATELY crank the motor over more as that will suck anything back down into the carb and suffocate any flames. Also, do not get gas anywhere outside the carb, for safety purposes.

Doing this will allow the motor to fire briefly and help pull fuel up out of the tank and into the carb. You will know right away when the fuel is in the carb as the motor will then continue to run if the ignition is on.

Don

 

[curtislow]

d

Use a hand pump oiler with gas in it. Pull the filter off the top and squirt a little bit in the carb just before starting. A bit of experimenting with how much is just enough may be needed. Put the filter back on before trying to start though as you might get a pop back through the carb if you get too much gas in there. The filter will contain anything that comes back through the carb. It is possible to get way too much raw fuel in there if you are not careful and get a bit of fire in the throat of the carb. If so, IMMEDIATELY crank the motor over more as that will suck anything back down into the carb and suffocate any flames. Also, do not get gas anywhere outside the carb, for safety purposes.

Doing this will allow the motor to fire briefly and help pull fuel up out of the tank and into the carb. You will know right away when the fuel is in the carb as the motor will then continue to run if the ignition is on.

Don

Does this not happen with the original carbs.I have the weber also and have the same thing goin on.My truck sits for a week at a time and sometimes longer.I never thought abot harm being done,does it do damage by having to crank for a little while before getting the fuel to the carb?

 

[brian]

It takes a long while for the engine to fire up after sitting just because the fuel has to get pulled up to the carb from the tank. I hate to think of the damage I'm doing to the cylinder walls as it cranks over for 20+ seconds before firing up.



Thanks

not sure what damage you're thinking about? if turning the engine over with an externally mounted electric motor damages the cylinders. what kind of damage are you doing by filling them with a flammable mixture and then igniting it to turn the engine over?
i like that the engine doesn't kick off right away after sitting a while. that turning it over also gets the oil flowing more before it fires up.

 

[Yellow Jacket]

I was thinking the cylinders would not get the same amount oil when the starter was just turning it over before it fires. If it's the same then it's not really a problem.

 

[curtislow]

I was thinking the cylinders would not get the same amount oil when the starter was just turning it over before it fires. If it's the same then it's not really a problem.

I only asked the question because I'm no mechanic and I try to fead each thing that kinda pertains to my fj40 situation. I kinda like the way my truck runs with the weber and an hei dizzy

 

[Yellow Jacket]

I only asked the question because I'm no mechanic and I try to fead each thing that kinda pertains to my fj40 situation. I kinda like

Same here Brother. Learn something every day reading on Mud. I'm not sure about Fuel evaporating out of Asian carbs, but I think I read it didn't happen as fast as it does with a weber.

 

[curtislow]

Same here Brother. Learn something every day reading on Mud. I'm not sure about Fuel evaporating out of Asian carbs, but I think I read it didn't happen as fast as it does with a weber.

Sometimes I think I drive myself nuts with wanting to know everything about the thing.But hey it's better to know what can go wrong than not knowing ,when things happen.

 

[SKULLYOTA]

When I had a weber and my '55 sat for a few months I had a large-ish syringe thing I got at an autoparts store (I think it was for two-cycle oil or something?), anyway I bought a small piece of brass tubing to make a "needle" out of an pushed it in the end. When I needed to pull it out of the garage, I took the air cleaner off, and filled the bowl with gas thru the bowl vent. It'd run long enough to get out of the driveway and pickup from the pump.

 

[handcannon]

The biggest concern I'd have with prolonged cranking would be overheating and damaging the starter motor. They are not designed for prolonged use. If you are having to crank a lot when starting then you are risking eventual long term damage to the starter. Crank for 15 to 30 seconds, and then let it set and cool for several minutes.

Skullyota's idea of using a large syringe to fill the float bowl is basically the same as what I suggested, get the motor to run briefly so the mechanical fuel pump can prime the carb.

Don

 

[Yellow Jacket]

Thanks guys. Good suggestions.

 

[curtislow]

Thanks guys. Good suggestions.

Thanks, I don't think I have to crank that long. I was more concerned with damage to the engine that someone previously mentioned.

 

[Steamer]

Years ago I installed an electric fuel pump inline just before the stock mechanical fuel pump. Before I crank I run the elect pump for 10-15 seconds then shut it off. Choke & two pumps and it fires right up with very little cranking. Even if it's been sitting for a couple of months. When I had the stock carb I could watch the fuel bowl fill right up. I switched to a Weber a few years back and it's still the same. It's a solenoid type pump & is not quiet but it's only on momentarily for the start. I was concerned about the restriction when not running that it might overwork the mechanical pump so I temporarily installed a vacuum gauge to see how much but I could not measure the difference between sucking through the elect pump or not.

 

[ken_79-fj40]

I had my old 79 set up like that too. Electric pump back by the tank that I rarely ever used but when I did it would just push the fuel forward. Started a lot quicker when I used it. The 68 I've been working on I put a TBI setup on and it's honestly very weird. Hit the key and it fires up instantly and idles smooth. Idles a little high though.

 

[ClemsonCruiser]

d
Does this not happen with the original carbs.I have the weber also and have the same thing goin on.My truck sits for a week at a time and sometimes longer.I never thought abot harm being done,does it do damage by having to crank for a little while before getting the fuel to the carb?

I know this was an issue on the early aisan carbs, FJ25/40s came with a hand priming fuel pump until around 1965

Just pop the hood and pump the handle a few times and you're good to go.

 

[Steamer]

I first put a squeeze bulb for an outboard in the line and it worked good for a few months. Then one time I went to prime it and I got a hand full of gas. I guess the engine bay heat got to it. Bad idea. Could of been ugly. That's when I went for the electric pump.