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Posted: Sat Aug 27, 2005 3:22 pm
by wayne
I suppose you have checked the screen in the bottom of the tank?
If not go there. otherwise see if there is good vacuum at the vacuum hose where it plugs onto the gas valve. like make sure there is some gas in the carb and start the engine while you have a gauge on the line. don't know how much is normal but you know 5lb will work, see if you got that much. otherwise ???????

Posted: Sat Aug 27, 2005 3:24 pm
by MySpree
where is gains michigan? near detroite at all?

Posted: Sat Aug 27, 2005 3:28 pm
by wayne
60 miles northwest of Detroit. 14 miles southwest of Flint

Posted: Sat Aug 27, 2005 4:42 pm
by MySpree
d***. well still you me and darat can go rideing. haha. um. yea and noise guy! but yea.

Posted: Sun Aug 28, 2005 9:35 am
by hondaman
If gas is not being delivered to the carb it has to be either the vacuum tube, fuel valve, kinked or clogged fuel line, or obstruction in gas tank.
How about a plugged fuel cap vent? Maybe? If all of these check out its got me stumped.

Posted: Sun Aug 28, 2005 1:15 pm
by Davcon
Well, I've been through that checklist at least twice and everything seems to check out OK. I replaced the vacuum line and the fuel line, the latter with clear line and no filter. The thing runs great (35mph after whittling out the intake manifold) but a bubble is forming and getting larger in the fuel line. We'll see what happens when it reaches the carb.

It occurs to me that it COULD be a lack of vacuum from the carb like Wayne says. But the problem stiill occurs even if I plug the fitting on the carb and manually draw 10-15 lb of vacuum with the tester while running. I can't see how that could be a carb problem. I just dunno. It's weird!

Posted: Sun Aug 28, 2005 3:26 pm
by noiseguy
Old petcocks will get "sticky" sometimes, and need more vacuum than the engine provides to initially open. After cleaning the tank and petcock per tech docs, spray some WD40 into the vacuum side of the petcock. This worked to unstick mine. The in tank filter also clogs sometimes. An acid clean will fix this if you can't remove it (I couldn't without destroying it.)

If you've got a rusty tank (even once cleaned,) plan on running an inline filter, unless you like cleaning carbs all the time.

Posted: Sun Aug 28, 2005 10:11 pm
by wayne
maybe take both lines off the valve. put gas in the tank. put a line from the fuel outlet in a gas can. hookup your vacuum tester to the valve and do a series of on and off checks to see how this valve is preforming.
I think noiseguy is onto something here.

Posted: Mon Aug 29, 2005 7:57 am
by Davcon
Here's where things get kinda hincky. Under that exact test, the flow comes and goes..............................OK one minute, no flow the next The tank is clean, the screen is clean, the valve is clean and opening with slight vacuum applied (off the tank), both lines replaced, with filter, without filter.............................everything. I figure it's GOT to be some intermittent sticking of the valve. But it doesn't respond to my ultimate test......................rapping on it with a screwdriver handle while motor running 8) .

Posted: Mon Aug 29, 2005 3:58 pm
by wayne
maybe take the screen out (I know it's clean but) put the valve back on, take the cap off the tank and redo the test. if you still got a problem with the valve I think you better start looking for a good valve. I have to assume you got lots of gas in the tank for this test.

Posted: Mon Aug 29, 2005 6:52 pm
by Davcon
Yep........................full. I'll try that, Wayne. What have I got to lose. The bubble got bigger and bigger............................let's just guess how THAT "movie" will end :wink: . Another thing it occurs to me to try.......a bigger fuel line. Maybe the engine vacuum is enough to open the valve, but not enough to draw enough gas. I really hate these crazy kinds of mysteries.

Posted: Mon Aug 29, 2005 10:20 pm
by noiseguy
I've always got a "bubble" in my fuel line. As long as the carb isn't running out of gas it's all good.

Posted: Tue Aug 30, 2005 1:29 pm
by Davcon
Because of the storm(s), I haven't been able to play with scooter stuff for a couple of days. Noiseguy, how big a bubble do you see? Mine fulled half the fuel line before I had to postpone further tinkering.

Posted: Tue Aug 30, 2005 9:15 pm
by noiseguy
Sounds about right. I have a filter about 1/2 way b/t the fuel tank and carb. Anything above the filter is usually air.

Posted: Tue Aug 30, 2005 9:18 pm
by Davcon
Well, maybe I'm OK now. Thanks guys. When things dry out a bit, we'll see if this one will stay running.