Revving the throttle in park it accelerates quickly and both squirters are doing their job. When I drive it however I have a hesitation when I punch the throttle. It doesn't really bog just acts like it is sucking air. I have checked for: Vacuum leaks, none Timing, initial is 11-12* total about 35 by 3000rpm Fuel pressure, solid 7-8#s Carb is a Demon (speed) 650 Cam is lumpy with a lot of duration stall is 3000 (sees about 2800) Ideas? What am I missing? The Carb is out of the box, no changes (yet)
You need to jet up on Demons fairly high from the factory. Is Mechanical or Vacuum Secondaries. Also The best thing you can do is rebuild your Demon from day one. You will find along with me and every other demon owner that you will get tons of fine particles that are left over from the machining/manufacturing product. Kit to rebuild is 25.00 from Jegs. Use the Barry Grant kit only I tried holley's kit NOT a good thing. It sounds to me as if you are lean.......... Bogs equal rich
BadMav, I adjusted the idle bleeds tonight per Demon. Now it runs a bit richer (good) but when I nail it from idle it pops through the carb. Hmmm now what? I guess I will order the kit but it seems odd to tear apart a brand new carb.
Popping through the intake is usually misfire or valves are adjusted too much......or worst case you are loosing a lobe on your cam.
I guess this probably isn't your problem, but once when my dist hold-down loosened up, the timing advanced itself a ton, and taking off from a stop, if i gave it more than a little gas it backfired through the carb. I still haven't gotten all the soot cleaned out of it. I'm guessing it was firing with the intake valve open.
BadMav, Not that. Only under initial acceleration. Bad valve etc would be a constant. Carb is not transitioning from idle circuit to power without going lean. I'll call BG tomrw. TXS
true i time ago they over came all that a few years ago.... put mine on right out of the box no problems i know of 4 others same way no problems ........ scotty p what fireing order you using some cams call for the 302HO/351w order .....some call for the old reg 302 order have seen both fireing orders run the engine with the wrong cam ....... they run like your saying
Guys, the car ran ok, just lean, with a holley. Put new carb on and this problem deveoped. 1-5-4-2-6-3-7-8 Tattoed on my forehead since age 13! New motor, same cam Just a new carb. It is a simple fix, ONCE I FIGURE IT OUT!! It is not timing, cam, flat cam or engine related. I firmly believe it is a carb adjustment
not sure what cam you are running but might need 1-3-7-2-6-5-4-8 fireing order most all comp cams use this fireing order
read my edit. Been running this cam for several years. 1968 302 block, never ran any other firing order with this cam and this is its 2nd motor.(you are 351w based. yes?) Thanks for the thought...
yes that firing order is 351w and for the 302HO engines sorry for giving my did not see where you have been running it for years with that cam....might be a low lobe ....try a vac guage set the Mix to the highest vac level ,,,,,maybe low level rear bowl
Sorry, just frustrated! New motor runs awesome once I get past 2000rpm, real awesome! Just want to get all the bugs worked out!
i know how it is ....went through 2 engines builds couse of a oil pan ...sure it has to be somthing simple ...let us know what you find ...did you get the video with it ??sounds stupid but i think they cover some on hesitation and poping back ....i was board and watched it
Demon's are known for needing tuned to run right but when they run right they really run right. I had a Road Demon on my 71 F100 for a while but traded the carb for my daughter's Maverick. Have you set up the secondary transition slot to show a square slot? According the BG that is the first thing to do then set up your 4 corner idle. To get my 625 to work right I had to go up to 70 jets in the front which was a bit rich for my 351w. In fact I never got it leaned out right really. clint
