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Author Topic:   akly floats( KP)
WPP
Member
posted September 09, 2004 04:43 PM
I am running a akly carb with a blp belt drive at one time i was running 3pds of fuel pressure at idle then i set my floats half way on the sight glass when i rev the motor the pressure goes up to 9pds then the float bowls are full of fuel iwas told thatwas the wrong way to set the floats it would be too much fuel. They told me not to worry about setting the floats at idle rev the motor to 7pds and the floats should be half way on the glass i done this and it seems to heat the engine alot faster but i just needed to be sure before i took it to the track like i said right now you can not see anything on idle but at 7pds of pressure it is half way on the sight glass i just don't need to burn it up thanks


KPLugnut
Member
posted September 10, 2004 07:44 AM
I agree with setting them at something other than at idle, but I'm curious just how low they are now at idle after you've done that. TOO low and you're sukin' air at idle (which is why it's heating up).
Then again, how often are you at a dead idle while out on the track, right?

It's one of those balancing acts that are played by many....my only input I might add is raise 'em high enough so you aren't idling with nearly nothing in the bowls, but NOT so high that the vent tubes are contributing to the fuel curve at WOT... :-)
And hopefully, you're using brass floats with that alky and they're not crushed from a backfire....

KP

WPP
Member
posted September 10, 2004 04:09 PM
Thanks the carb is a braswell and it came with 142 jets and 140 now i have 140 and 138 . The carb has a big sight glass i really can not tell were it is at idle so i may start raiseing it up a hair or two how can you tell and also how should you set the four idle screws 1 1/2 or 1 turn thabnks for the help


KPLugnut
Member
posted September 10, 2004 06:39 PM
With alky carbs of that "flavor", we start at about 1 1/2 turns out from lightly seated on the idle mixture screws, then do the proper adjustment with the car idling. Preferably, use a vacuum guage to read manifold vacuum and fine tune each corner to get both best quality idle and peak manifold vacuum at idle.
Goes without saying that float level should be set close to optimum as well as fuel pressure first, which you pretty much already are.
It's really hard to say that every carb should be at some number of turns on the skrews because there are too many variables there, right down to slight variations in the distance from the last thread on the skrews to the seat area of the tip of the things and the seat inside the block.
This is why it's best to do it via the method above, or a similar way which most carb builders recommend.
Your jetting sounds pretty much in the ballpark but that's impossible to confirm without seeing the carb for myself.

Hope I didn't ramble too much.

KP


WPP
Member
posted September 12, 2004 01:48 PM
Well i played with the carb this morning right know at idle i have 3pds pressure and the fuel is right at the bottom of the sight hole.I also set the topend pressure at 8pds to 8 1/2 pd. The float bowl does not fill up at 8ds they are 1/2 to 5/8 on the sight glass when i rev the motor so do you think this will work and i have never used a used your way to set the idle screws the only thing i know is the the backs on each side kills the motor the front one do nothing how do you use this gage hook it up and everything else i never had done this what should it read sorry for all the question thanks


KPLugnut
Member
posted September 12, 2004 03:04 PM
If the front idle skrews do nothing, then the primary butterflies are too far open at idle and there isn't any signal getting to the primary idle circuit because you're idling off the midrange/main circuit.
To correct this, drill or enlarge the existing holes in the primary butterflies until you get the same idle rpm but are able to close the front butterflies down so that there is only about .030" of the idle transfer slot showing underneath the butterflies.
Start with about .090" holes and work from there.
Yes, where you have the float levels set now will work just fine, but you're giving up throttle response and midrange power if you're not utilizing the primary idle circuit.

On the vacuum guage method of idle mixture adjustment, yes, just hook up the guage and see what idle manifold vacuum reading you have. The actual reading varies greatly from motor to motor, carb to carb, cam to cam, etc etc...so don't worry (yet) about exactly what the reading is, just try and maximize it.
This is also a good benchmark reading to know when picking the right power valve(s).

Hope that helps,
KP


WPP
Member
posted September 13, 2004 03:55 AM
Ok kp last night i idle down the motor to about 1000 rpms then the rear idle screws would not do nothing but them one on the front would i have not drilled anything yet there are holes drilled in them but i have no idea what size they are.


WPP
Member
posted September 13, 2004 04:34 AM
idle mixs screws on the above post


KPLugnut
Member
posted September 13, 2004 06:44 AM
It's that "balancing act" that you'll have to play with when adjusting both the front skrews and the back ones. As long as the idle circuits in both front and back have been isolated from each other (some builders used to forget to do that), then the fronts and rears should function independantly.
If you've got no adjustment on the fronts, their butterflies needed to be closed down a bit, and if you've then gotten no adjustment on the rear, then they too need to be closed back down some.
It's sometimes a PITA to deal with on some carbs.

KP


WPP
Member
posted September 14, 2004 06:36 PM
KP THANKS FOR YOUR HELP I ENJOYED THE TALKS WE HAD ON THE PHONE I WILL LET YOU KNOW WHEN I BOX IT UP. THANKS


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