ClassicCar

Majumbo

So I got my car up and running again and test drove it around and it kept stalling out and it would be hard to start afterward. My accelerator pump isn't working anymore and I don't know why. I pulled the top of the carb off and manually pumped it with my finger and it worked pretty good. I rebuilt my carb not to long ago. It's weird because there was like a bunch of crud in there. It might be the ethanoled gas but idk. Any help? Plus it's weird because the pump has like a sleeve with like a slip joint that let's the plunger go downmore. Idk please help!!!

Majumbo

Anybody?

Jon B

So, when you take the air cleaner off (when the carb's on the car) and you pull the linkage (or have someone in the car press on the accelerator), there is NO "shot of gas" pushed into the carb by the pump? Yet it pumps when you have the carb on the bench and turn the linkage with your fingers?

Is it possible that there is a completely different problem, which you think is the accelerator pump?

GrimGreaser

Fuel filter/screen? I spent a week fighting an engine that wouldn't run. Guess what, inlet screen completely plugged. After some cranking enough fuel would get in so it would appear to be getting fuel, but as soon as the throttle opened it would die. Yeah, felt like an idiot.

Another thought, Elevation? I live around 6000 ft, and with the pump on the outer hole of the pump arm (WGD) it stumbles really bad right off idle. Rich enough that i can kill it if i get a little happy with the foot-feed. I have moved the pump link to the inner hole, no stumble now but a little flat from a stop. Carb is freshly rebuilt, but I have some more tinkering/checking to do.

Majumbo

Moved the pump link to the inner hole. Where exactly is that?

GrimGreaser

Assuming you have a WGD...

[attachment=11739]WGD-Pump.JPG[/attachment]

Not the clearest picture, but it'll tell you where to look.

When you rebuilt, did you check the pump travel as per the manual?
Available here: http://hetclub.org/index.php?option=com_wrapper&view=wrapper&Itemid=98

Majumbo

I'm pretty sure I did but I forget. It used to pump pretty well. The thing I'm worried about is the plunger has a sleeve and what I think is happening is when I assemble the carb, the first shot will push the plunger down And swift pretty well and then when it's retracting, it's just pulling up on the sleeve like a slip joint and not retracting the plunger. I'm going to pull it off and clean it up again and see what's up with it. I'll get back to you on the plunger position to the arm.( which hole I mean)

GrimGreaser

So you get one good shot then not much afterwards? Check the check-ball in the pump well and the check-needle under the discharge nozzles. They could be getting stuck. All your pump springs in place? One in the well and one on the plunger assembly?

Majumbo

Which springs are you talking about? I have one under the plunger which is probably the one in the well I'm guessing. I don't think I have the plunger assembly spring you speak of. Where is that located? And yes sorry it's a wgd

GrimGreaser

There's a spring on the plunger itself:

[attachment=11750]WGD-PumpSprings.JPG[/attachment]

Also, I have been tinkering with mine over lunch... Not sure if it's the pump causing the stumble with mine now. Might be that the rods pop up to the power step too quick, or the power step is too rich for my elevation.

Tallent R

It sounds to me like you answered your own question . You said it was running fine after you let it set for awhile now it has a gummed up carb.
Get som Yamaha brand carb cleaner from a motercyle shop or on line. And use it as directed and it will clean out the gum and it will work again.
Roger

Majumbo

Yeah I don't have that spring. I'm pretty sure I didn't have that spring in the first place. Does your plunger have a sleeve and slip joint? Maybe I have te wrong plunger? And yes the carb probably needs to be cleaned but that wouldn't explain the plunger stop working would it?

GrimGreaser

My plunger has the slip joint. The spring acts as a delay so the pump shot is a nice stedy stream through the whole throttle movement, regardless how fast you open the throttle. Edelbrock Performer pump plungers are the same setup, so maybe you can use the spring and retainer from one of them if a WGD one can't be found (haven't confirmed, this... but they sure look close.)

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