i have a road demon 625, all was well until I had to replace the needle and seat, so I did a basic rebuild with new gaskets and all. The accelerator pump is barely dripping fuel when I pump the throttle, as well as pumping the accelerator arm by hand. It takes a few quick pumps and then it starts to barely come out. It's not a adjustment issue. I've gone through the whole carb with an air hose and carb cleaner. All rubber, gaskets and orings are new, bolts tightened etc. Why would the pump not be working if there are no blockages?
The first accelerator pump wasn't bad, but I figured I'd replace it anyways with the rebuild kit. I have 2 rebuild kits, plus the old accelerator pump, all of them do the same thing.
I never trust an air hose to blow out all the passages,so I use a small rubber line,like a wiper hose,and blow thru them with my mouth full of smoke from a cigarette,I then can see the amount if air passing thru the passages,,If you do not smoke,that small amount of smoke will do you no harm..
I'm not familiar with the internal workings of that carb but snooped on their site and the setup looks pretty simple. Did you put the new cup on the accelerator piston in the right direction? Is the check valve in place and working right? Is the accelerator pump transfer tube in good undamaged condition?
I like Mr48 am not familiar with that carb.but some I have rebuilt had a small steel ball in pump well if missing it allows fuel pump back out instead of sealing allowing pump to send fuel to squirters.as I said not familiar with that carb just a thought easy for it to fall out when turning carb when checking passages etc.
Did you replace the 'umbrella' seal? Its that orange seal between the float bowl and accelerator pump. If the old one was left in place and carb cleaner contacted it then the edges curl up and it won't act as a seal/checkvalve. What can happen is you push on the accelerator pump an dit'll send the fluid back into the float bowl. If replaced, the umbrella side is in the accelerator pump cavity, not the float bowl - it can be installed upside down.
I've found with todays ethanol based gas its really hard on rubber parts, like accelerator pump diaphragms. They tend to dry out and lose their ability to pump fuel. Seems to be more of a problem if your car sits for a week or two.
Ya I pretty much did everything you guys mentioned. Replaced umbrella, nozzle is on the right way, tried multiple accelerator pumps. It is a very simple design, that's why I can't see why it's not working. There's only 1 passage from the pump to the bowl, and 1 passage from the bowl through the metering block and out the nozle. And it's not blocked! Only thing I can think of was maybe there was a oring in between the nozzle and carb where it gets screwed down?
Ya I'm not sure what's going on, something has to be missing at the nozzle assembly though. Right now it's the brass screw with crush washer, through nozzle and screwed into carb. The hole it gets screwed into has the needle and seat in there, and clean. The one thing that's a little weird looking to me is that the screw isnt hollow to allow fuel to go through. But the hole it threads into has slots on the sides to allow Fuel to get by with a solid screw. But if I use a gasket or oring between nozzle and carb it would block those slots. It would have to be a perfect fitting gasket with slots in it, in order to seal and allow fuel to get by. Anybody have an idea what I'm talking about? The rebuild kit doesn't include any gasket that would work. And I don't remember a gasket coming off when I took it apart. But that could have slipped by me
That is the 'squirter' screw. It isn't hollow in the 30cc pumps and the 'needle' down in there is called an 'anti-siphon' slug, it is a weight that fuel pushes against, it raises and fuel flows thru the slots and into the squirter, there is a thin washer that goes under the squirter and another identical one that is on top of the squirter beneath the head of the squirter screw, they seal the squirter so fuel only passes out the holes. Another possibility is if you used the wrong metering plate gasket. They provide a few different ones in a kit, the gasket you want has a cutout the shape of an upside down tombstone, just above the cutout will be a small hole right in the middle (1/8th or so), that is the hole for the accelerator pump shot. They might have given you another metering block gasket that has upsidedown tombstone cutout with another small tombstone cutout at the top, that is for a different type carb that has a transfer tube for the accelerator pump shot, if you used this gasket the fuel in the accelerator pump will get squirted right into the cavity the powervalve resides in and then dribble into the engine thru the vacuum passage and the engine will run extremely rich at idle. Lots of people have made this mistake. When dry and you push on the accelerator pump you can hear the air thru the squirter.
Thanks for the input. I know I'm not using the wrong gaskets. I've chased and followed that passage way 20 times with and without the Gasket on there. I can hear the air being pumped dry out of the nozzle. But every time I bolt the carb back on and get fuel in it, it's like its trying to pump air and fuel. Fuel won't squirt out unless I give it a hard, quick pump, and by no means would that be considered easing into the throttle. When I press the pump by hand like I'm easing into the throttle, it will either gurgle like it ran out of gas, or it will leak down the nozzle without giving a squirt. Like I said, I can get em to squirt. But it is very inconsistant and takes more of a pump than my foot would ever deliver
Interesting, time for a picture. It does sounds as if the fuel is going back into the bowl instead of to the squirter. Can you take a couple pics of what you have?
It's likely that there's two check valves in the accelerator pump circuit. Here's kind of a generic view to show the layout... When the throttle is pressed, the fuel outlet check valve opens and the fuel inlet valve closes. When the throttle closes, the check valves function in the opposite manner... Outlet check valve closes and the inlet valve opens.
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