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I do know the nozzles aren't flowing during idle. I've never heard of initial timing over 20deg though. This thing won't run decent till it's over 30 and you'd think it would spark nock at that. I have a curved and welded distributor from FBO and set to 18 initial and 35 at 3Krpm. I think it's the carb because before I tried to lean it out it ran good. Could it be I'm not letting it get warm enough to set the timing? She's cold blooded for sure. An earlier post said to set the floats below the sight glass but it ran fine with them at half. It's a 650 Demon double pumper w/ mechanical secondaries. It came from the factory with 72 front jets, 6.5 powervalve, and transfers slots set to .020. To try to lead it out at idle I took a vacuum reading in drive at idle and had 8.5hg. So.. I pulled the 6.5 powervalve out and placed a 3.5 in it, cranked the idle mixture screws in 1/4 turn from 1-1/2 out and changed the front jets to 67's. it seemed to run to lean so I then pulled the 67's out and put 69's in and a 4.5 power valve. I'm not sure what to do now. You can't even make it idle to set the initial timing. Would a vacuum leak cause this?

Someone told me that I may have jumped a tooth on the chain but it's a dual roller and I doubt it.



First thing too do it pull the carb off and take it complety apart.

Demons are know for poor quality control.

My demon carb was doing the samething found lots of metal shavings in the new carb.

Which demon are you running speed, road etc... ?

Demons you set the floats a little different then a holley the clear sight plugs has 3 lines around them each is a different level for the float to be adjusted to try the bottom line.


Also what kind of fuel pump and pressure are you running to high of a fuel pressure could do this.

Also do you have or know someone with another carb to swap out and try to see if you can get it to run.