Topic: help needed with testing accelerator pump

[juntjoo]

so I've found no leaks in my carbs, floats hold the fuel, but the accelerator pump isn't working right and I don't know why. As you can see it's squishy. I guess that means with air. And would this be because the rod's boot isn't on to seal it there around the rod shaft where I noticed air and gas bubbling through? Could there be something wrong with the diaphragm that I just can't see? Seems to fit perfect all the way around it's edge, no tears or holes

[TwoTired]

Did you "prove" the two check valves both seal and allow fuel flow in the opposite direction?

[juntjoo]

Did you "prove" the two check valves both seal and allow fuel flow in the opposite direction?

are you talking about inside the cap? what exactly do I do? I just read to spray into the large hole to verify it goes out the others. How do I do what you're suggesting? Thanks

i dont even know how it works. trying to figure that out atm...

Okay, so, only the passage going to the fuel rail should take fluid, while one next to it and the square in the hole in the middle/top one both should block fluid/air correct? I'll assume so till told otherwise and try to find something ro fit ovee that hole on the other wide to apply vacuum. I've got a hand vac already...



here :

https://imgur.com/a/p94ix

that hole in pointing to i applied suction and it went through. It's that defective then? I'm guessing when the plunger is depressed it's all supposed to go to the fuel rail, where mine is going there AND back towards the bowl. I may have an extra cover that will work...

[TwoTired]

At the bottom of that square plug in the center of the cap is a ball and seat.  There is another in the carb body near where that cap goes.  Those ball and seats are check valves that only allow fuel to go towards that fuel rail.  I clean those with pressurized carb cleaner and various tubings to seal the flow of fluid.   Fluid should only go past those square plugs in one direction only.

Cheers,

[juntjoo]

if I understand correctly, there is a ball in there that when pushed against the square side fluid passes but when pushed to the other side it sits in a spherical seat to create a seal in that direction? I youtubed the term and saw a couple videos on check valves but more complicated ones.

okay, so if I can push/pull air the wrong direction that ball must be stuck with corrosion or something? is it possible they are permanently broken by corrosion. Both valves aren't working and my carbs weren't THAT dirty and I soaked all parts for a couple days. Im confused as you'd think if both of mine aren't working I would have read about other similar cases but I haven't. Is this common? As I type I'm soaking them and Ive used a thin wire on them too.

[TwoTired]

I've had several that were stuck from gummed up gas residue.  I used aerosol can carb cleaner to clear them and then ensure they would only flow in one direction.  What are you using for the soak?

I've never had to do it.  But, some have yanked that plug out to access the little ball and clean the cavity.
I don't like pulling that square plug.  I think it's pretty hard to do without causing damage.  I believe they are nylon plugs, though.  So, it is possible to make a replacement plug, if you can get some nylon material to shape.

On the PD carbs you can assemble the pump onto the bowl, put some gas in in the bowl and actuate the rod to test pump function, before putting it on the carb.  Best to have eye protection if it is working.

Cheers,

[juntjoo]

I've had several that were stuck from gummed up gas residue.  I used aerosol can carb cleaner to clear them and then ensure they would only flow in one direction.  What are you using for the soak?

I've never had to do it.  But, some have yanked that plug out to access the little ball and clean the cavity.
I don't like pulling that square plug.  I think it's pretty hard to do without causing damage.  I believe they are nylon plugs, though.  So, it is possible to make a replacement plug, if you can get some nylon material to shape.

On the PD carbs you can assemble the pump onto the bowl, put some gas in in the bowl and actuate the rod to test pump function, before putting it on the carb.  Best to have eye protection if it is working.

Cheers,

thanks. yes, I've looked around and indeed this happens often enough apparently, and I have found the guide to taking out the plugs if need be. nylon? i thought that was brass or something. okay, I'll get it. thanks

and I'm using regular carb spray and soak(in a big bucket).

[juntjoo]

https://imgur.com/a/cXz5C

can anyone confirm for me, someone with a set of carbs out, what's supposed to happen here? On all four sides I can insert it about 4mm tops. Shouldn't I be able to push all the way through(and presumably with the othe check valve too)?
I apologize if I seem a bit inept but I guess I am and I usually have to break a couple things before fixing something. it's a it's the bad kind of 2for 1 lol. Matter of fact just burnt my pump cap with my torch(common sense to most "mechanically inclined") and had to sand it back to flat. So each question I ask is intended to save me on average $10 I reckon using rough math. So thanks ao much anyone having a moment to check. This one is quite the biotch

[juntjoo]

so I decided to volunteer/sacrifice my extra cover to r&d drilled out the plug to uncover the mystery beneath and I'll be danged:

https://imgur.com/a/UAIeR

I can actually save this if I didn't destroy my other cover if I can somehow furnish another metal plug somehow. I suppose I could sand a piece to fit. geez what a PITA maybe Ill check ebay first if it wont cost me an arm

let me first test it  now it's free. it should just suck back into presumably a half spherical seat and block the passage....

[TwoTired]

What does your carb cleaner spray list as ingredients?

[juntjoo]

What does your carb cleaner spray list as ingredients?

acetone. huf puf huf... any more ideas? I'm about to head to the hardware store see if i can find one of those headless allen socket screw. I tapped the hole to use a screw as the plug but the head will impede the plunger, hence to the store.

So I've got the one i drilled the plug out, and another clogged one but even originally dirtier than the other one so I expect it to be just as or more stuck. so either

A) try to plug hole then hopefully be able to drill hole through middle of screw or other method or
B) try to clean the other

plus I have the one in the bowl cap.

or maybe I'll check out honda. see if i can make it out there without too much a fee

[TwoTired]

Seems acetone should do the job.  The better carb cleaners used methylene chloride, which you can't get in California anymore.

Paint strippers used this, too.  If you can find it.  Very aggressive.  If you find it be wary.

Those ball check plus are square to let fluid pass.  A set screw in it's place will block fuel flow. FYI

You might check a hobby shop to find brass stock with which to make new plugs.  As I mentioned, I found some use nylon plugs instead of brass.

Cheers,

[juntjoo]

Seems acetone should do the job.  The better carb cleaners used methylene chloride, which you can't get in California anymore.

Paint strippers used this, too.  If you can find it.  Very aggressive.  If you find it be wary.

Those ball check plus are square to let fluid pass.  A set screw in it's place will block fuel flow. FYI

You might check a hobby shop to find brass stock with which to make new plugs.  As I mentioned, I found some use nylon plugs instead of brass.

Cheers,

thanks. i found both the bowl and accelerator pump cover check valves verified for $35. I think Im gonna grab them.

[juntjoo]

everywhere I looked about this indicated these pumps need to work like squirt guns, and I couldn't get much more than squishy action out of the cap itself or the nozzles in the carb throats, So got one clean used one. After checking all I try again and if it's still behaving like this off the bike I may throw them on and see what happens

[TwoTired]

I generally test the pump and check valves by assembling the pump onto the bowl,  Put gas in the bowl and actuate the pump rod.  It should push gas from the bowl out the discharge pathway (to fuel rail) with vigor.

Cheers,

[juntjoo]

I generally test the pump and check valves by assembling the pump onto the bowl,  Put gas in the bowl and actuate the pump rod.  It should push gas from the bowl out the discharge pathway (to fuel rail) with vigor.

Cheers,

yes, thanks for the confirmation . that's what ive seen in vids. Can't wait to overcome this little hurdle. A great lesson it will be. I don't think these things are generally serviceable. I brought it to a guy yesterday and he followed what I was going through and took my parts and was about to furnish me up new plugs but I noticed he didn't seem to understand how to test them, and I found them used(cleaned and tested at least), a pump cap and carb bowl which I probably don't need, so I took my parts back and test my luck with another round at this. I'll try boiling them in water this time. the torch last time was overkill lol oops.