Yf938 Carb Rebuilding Questions

So I finally got around to rebuilding the original carb a yf938 yesterday but have two questions as it has been a while since I disassembled and cleaned it plus it was missing a few things when I took it apart.

First the kit came with 4 springs 1 small one that goes to the air/fuel mixture screw, the big one that goes on the bottom portion of the accelerator pump shaft then two other ones. that are the same length but one has a bit more diameter then the other. The previous owner had both of these on the top portion of the accelerator pump shaft. Is that correct didn't seem that way in the videos I've watched or in the diagrams I've pulled up.

Second, there was nothing in the "weighted" check valve spot on the carb when I took it apart. The kit didn't come with a new ball but came with the weighted pointed thing instead and also the one for if you had a ball there. The weight pointed thing is so long there is no way to put the spring clip holder above it to keep it in place. Doesn't seem like a problem to me as the thing is held in place by the gasket which is solid above it but does this all sound right to y'all? hoping to see how she runs with the original over a solex. Thanks!

 

Yes. That is the correct installation. There are three tests to perform before the top is installed. The bowl and throttle should be fully assembled for these tests.
1. Hold the accelerator pump shaft all of the way down. Make sure the metering rod bracket is level with the accelerator pump actuator.
2. While still fully down, check the eye of the metering rod for .005" clearance or less from the pin it rests upon while the rod is all of the way down. It should move freely along the length of the short pin.
3. Fill the bowl halfway with camp fuel (White Gas). With the pointed check weight in its hole and your finger over the discharge port in the center column, pump the accelerator until the column with the weight fills with fuel. Holding that, count for ten seconds. If it stays full, all is good. If it doesn't and you have the correct-sized check ball, remove the weight, insert the ball, and using a brass drift placed on top of the ball, and a light brass hammer, hit the drift gently 4-5 times. Remove the drift and ball. Reinsert the weight and test again. Repeat as necessary but BEWARE. If the ball becomes stuck you'll have to remove the accelerator pump and blow high-pressure air through the circuit to free it.

 

Okay so no need for the spring on the pointed
Weight then? What about the springs. Have two the same length. Do they both go on the top of the accel pump shaft or just one. Only see one in videos and the diagrams but a po rebuild it well non working of course with 2
Up there one inside the other. Much prefer a simple carb like an amal monobloc. These seem quite fiddly.

as i said i have no check ball. Nothing was in there and none came with the kit.

 

Yes. The two same-length springs are placed, one inside the other, over the top of the accelerator pump rod. No ball, good luck. When properly built, set up, and adjusted the YF is a good carburetor. Understand that if there is side-to-side play in the throttle shaft then bushings and a new shaft would be in order.

 

Yeah, but a pain to open the hood and 'tickle' an Amal on a Jeep every time you start up.

 

The Carter YF is a fairly simple carburetor, and a very good, reliable carburetor once it is setup properly.

The only "fiddly" thing about them is adjusting the metering rod, and even that isn't so hard to do.

 

It ain't no Monobloc. lol of course the thing doesn't run very well with it. Back to the chinese solex

 

Mine runs great with a Carter YF

I have been rebuilding my own carburetors for nearly 60 years and while these seem simple to me, I can understand why they might baffle someone with less exposure to such things.

 

Having rebuilt a couple Bosch K Jet metering heads, I call a spade a spade, the Carter is quite fiddly. I'm sure it can be set up decently but got 3 of em going to the metal man next time I go. Would have been nice to go original but not worth the expense to have another person look at as they were all pretty roached to start with. Was shocked how well the borrowed ultrasonic cleaner did on the shell but all for not.

 

Send them to me. I will gladly pay for the shipping.

 

Please don't trash them.