Thanks so much for this, Warren! The whole deal with checkvalves has been a question mark in the back of my mind for a while now, but this really explains it well and showed me how to confirm one way or the other whether they’re the issue with a carb. Good job, buddy! 👍
Hey, Warren, it’s 2 months later and I’ve been experimenting with a C1U carb I got in a box of free parts from a customer. I followed your instructions at 5:35 to drive the brass check valve out and test it. I had to remove the choke plate and rod first so I could get the check valve out. The valve tested fine. I went one step further by removing the adjustment needle that feeds that check valve and ran a 9 gauge guitar wire through the orifice all the way into where the check valve seats. Got it all back together successfully. Thanks for one more piece of the carburetor puzzle learned! 👍🔧
great video with lots of check valve examples and a rare video on main jet removal. thanks! here my tip, check valves can be removed by prying them out with select sized drill bit bottoms. then cleaning that passage is easier and with inspection and careful placement of the diaphram disc, and pressing the brass piece back in one can get good results.
Very good information my good man! I have at least a hundred of those carburators in a box, And I have a vintage chainsaw collection of at least 60saws! So I had to learn everything I could about them. But that frickin check valve had me stumped when I first started working on stuff I remember hearing some ol boy that owned a small engine equipment repair shop in Greensboro Kentucky say that the check valve was made out of Neprene like they use for fishing waders. I don't think most people know what they are doing with these carburators and they don't realize it when they pull the fuel lines off and don't remember which fuel barb that they go back on! But there are two styles of the priming system for these carburators, one is a purge ball and one is a primer ball! And the one that is separated from the carburetor and is clipped into the side body panel draws the fuel backwards from the fuel tank, into what would normally be the outlet on most carburators, And out what is normally the inlet and into the shorter fuel barb marked in on the reverse side of the primer bulb and out the longer fuel barb and then back into the fuel tank! When you pump the bulb.I take it that carburator body does not have one of these check valves in order to accomplish this?
Wow, what a perfect explanation re: check valves. One question, in your many experiences, what might the symptoms be of check valves that are not working right? Is this one of them ….immediate engine flooding when trying to start? Thank you so much for this video.
Yes, that could be a check valve problem. The minute you tighten down the gas cap, pressure starts to build up inside the gas tank. That pressure will push the gas up the fuel line, through the carb, and into the engine. The machine could be flooded before you even pick it up. If you replace a carburetor, only use the genuine OEM carb or buy an aftermarket carb made by Hipa.
Thank you so much for your prompt reply. That makes complete sense, since after trying to start it and continuing with the repair, removing the gas lines from the carb, gas would flow out of the tank, really bad, until I removed the gas cap. So a new carb is the works. Thanks again!
@@dsnako1 When you’re not using it, set it upright with the gas cap loose. Then right before you try to crank it, tighten the gas cap down. This will prevent it from just sitting there pushing gas into the carb when you’re not using it.
Warren, I appreciate your video which I wish I would have viewed a year ago. I made the mistake thinking that most of the check valves had a metal flap like a car PCV valve. I made the error of trying to clear a clog with a wire brush fiber. The thin wire punctured the rubber-like flap which ruined the valve. I took a fine pick and jewelers screwdriver to remove the Welch plug and see what was inside the valve. I was not sure if spray cleaners would destroy the flap. I would like to know if you or any viewers have had good or bad results running the carbs with check valves in an ultrasonic cleaner.
I'm not joking, I have literally rebuilt probably at least 1,000 carbs in the last 15 years. Sometimes they work, but other times, no matter what you do, can't get them right? It's the tiny check valves that are usually the issue. Hard to blow air through them, cause you can blow the valve right out of them if you use shop air, has to be regulated to like a few psi? Most mechanics think they can work on a simple little carb, until they can't even put the damn thing back together? It takes experience and a lot of patience, believe me?
With the carburetor fully assembled, you can just hold it in your hand, stuck a piece of fuel line onto the inlet of the carb then stick the other end of that fuel line into the gas tank or a jar of gas and pump it. If the check valves are good it will shoot gas out of the return
If the check valve is stuck open or shut just because it’s dirty or gummed up, an ultrasonic cleaner could get it to work. If the check valve is damaged it wouldn’t help.
What do you use to clean the internals of the carb out? I would use brake cleaner and blow them out with air. Carb cleaner is a no-no with rubber o-rings and gaskets? It will swell them up like twice their original size, and take like 24 hours to shrink back down. You'll learn that the hard way the first time you make that mistake?
Sir what's would make a bg56 idle great but when you rev it up it bogs out on the high side. It's not the muffler screen. It there a way to clean the high side circuit?
I see alot of diy folks who destroy the check valves with welding tip cleaner If it’s plastic peace I install new one but other than that I installed new carb
@@zulkiflykadir8049 There’s no such thing as a compression test on the carburetor. Not sure what you’re talking about. I’m talking about the compression in the cylinder
