toolz

I'm using a list 8896 dominator on a 555 " N/A motor. It's jetted up slightly to be safe. Mixture screws are at 1/2 out on primary and 1 1/2 out on secondary. Motor responds well to screw changes, meaning it's not overly rich, but it won't idle well in gear when hot. I don't mean to hijack the thread, but I would like some suggestions. I'm installing a MSD box this weekend, and opening up the plug gap a little. I hope this cleans up the idle, but I may have to drill some air bleeds in the throttle plates like I used to do on the drag carbs. Any help would be appreciated. Again, sorry for the walk-on.

ratman

dan i'll call you in the am, ratman

go ahead hijack the thread i have the same problem with my motors exactly, ratman

toolz

Installed the MSD, gapped the plugs at .050, drilled two 3/32" air bleed holes in the top of the carb near the air cleaner stud. I'm now able to back the mixture screws out a little more, and the motor responds to adjustment better. Won't get in the water till next weekend, but I've got high hopes. Any other suggestions would be appreciated. Thanks.

ratman

toolz, send me a pic of where you drilled your holes in the carb. thx, ratman

ratman

i got one of my engines idling beautifully, 1000/800 in gear. the other still won't idle worth a chit though.

toolz

I can get pics, but not for a couple of days. There is room at the center of the carb, right near where the air cleaner stud screws in. The best way is to drill and tap the holes so you can use fuel jets for the air bleeds, making them adjustable with different jets. I didn't have the right tap (it's an odd size), so I guessed, and came close. I put one hole in front of the stud mount, and the other to the port side. The starboard side has a lot of aluminum cast under it, so no holes there (words of experience!). You can do the same thing with holes in the throttle plates, but this is easier. I was able to close the throttle plates farther after drilling, which makes better use of the idle circuit instead of pulling some idle fuel through the mains. A smaller cam wouldn't cause these problems, but big motors need big cams. Hope you get yours running good. Toolz

ratman

toolz, i've never done or seen this done and don't wanna f something up please get me a pic and let me know how your motors are idling after you get em fired up. the thing is my one engine idles great the other wont!

Airpacker

800 in gear? kinda fast isn't it? With some tuning, you should be able to get that down to 5 to 600 in gear no problem. my old 540 with a 650 lift cam and a 1125cfm dominator would idle at 475 in gear all day long without loading up. As for air bleeds, sometimes on a dominator, one 1/16 to 3/32 hole on each throttle plate 1/8 in from the edge inline with the idle port will relieve some vacum and let the idle lean out a little. start small because yoo can always drill bigger but its real hard to drill smaller. If your jetting is on and you can't open the mix screws at least one full turn, you may have to reliev the vacum some.

Cmoney

Where is the best place to hook up the vacuum gauge?

ratman

im happy that it friggin idles at all at this point. it really sucks that randy and his boys at cobra power did such a lame azz job on my motors whern they dyno'ed them, id be boating now not crying out for some help