Buller twin carbs loading up

tank vent? if you pull fuel lines from carb. inlet does fuel flow freely? if it does i would replace the diaphrams, check popoff pressure, top carb. should be 8 psi, bottom carb. 7 psi. also check fuel screens in the fuel cap for clogging? also if you are running an inline fuel filter i would discard it, and run fuel line from tank to carbs. what size are the tank fittings? just some things i have found with my dual carb. setup :) hope this helps.
 
Ok Taking Jacks advice and put some wd40 on diaphragms. Don't have any extra diaphragms here at the house so I am going to do what I can today. Sprayed diaphragms and they seemed to soften up. They were dry and stiff. I'm going to let them sit for a bit then put it back together. BTW tank is vented properly, no problem there.

I'll let you guys know.

Thanks,

Hoppy
 
when changing diaphrams they go on first to carb. body, then gasket, i had this wrong and it wouldn't pump fuel because the diaphram was to far away from the arm that activates the fuel charge? does this make sense?
 
Well out of options for today. I have had carb on and off three times and engine on and off three times. Thats enough for today. Looks like I need new diaphragms.

Hoppy
 
We purged both carbs after last race. 5 weeks ago. John has some new diaphragms coming to me. Thanks John.

Hoppy

Hoppy
 
animal 77, gaskets go on body first then diaphragm, then, gasket then skin and again if a double stack, that's the way the carb was designed and the way to have the correct fulcrum arm height relationship at .065 below the bare body for alky. That's not the reason your carb wouldn't pump fuel, the diaphragm has more than enough travel to overcome that distance. Jon
 
animal 77, gaskets go on body first then diaphragm, then, gasket then skin and again if a double stack, that's the way the carb was designed and the way to have the correct fulcrum arm height relationship at .065 below the bare body for alky. That's not the reason your carb wouldn't pump fuel, the diaphragm has more than enough travel to overcome that distance. Jon

i'm not questioning your authority on the tilly's but it didn't pump fuel on a double stack 34mm methanol tilly carb. I had until I put the diaphragm first, and then gasket. it might be different on the buller dual carbs? or maybe I had something else out of adjustment? I had the popoff set at 8 psi, and fulcrum height at 0.065 according to the gauge I used with no gasket, ( bare body ) and this is only from my own experience...... is it possible I had the diaphragm in upside down?
 
Naw, couldn't have been on upside down the pins and the bolt pattern wont let you do that. I don't know why it didn't work for you that first time out , all I'm saying is that even with the gasket on first , the diaphragm has more than enough movement or travel to bottom out it's disc on the area around the trench the fulcrum arm is in. It may have been the diaphragm had dried out enough to have had limited movement, so it needed to be closer to get the needle open, that's most likely.
 
thanks jon, it was a new diaphram :), I did have the gasket first like you stated..... one of them things that make you go hmmmm?
 
Lots of cursing going on in my head right now. New carb kits. Same problem. Won't draw fuel. what am I doing wrong?

Hoppy
 
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