2276cc sputters on accelleration, Weber tuning advice needed

[JimmyBaja]

So I've only owned this buggy for a month and I'm going off what I know. See specs below. Compression check excellent, we've adjusted the valves, synced the carbs and she idles and revs nicely. Under load on acceleration she sputters and pops a bit: does not run smooth from 2.5k-3.5k rpms. Loves to run up high in the rpms and rolls along fine at 2k rpms.

Engine: 2276cc, Engle cam, HiRev Dual Spring Lifters, EMPI Big Valve Heads, EMPI Fuel Pump with Regulator, D8EA spark plugs, MSD 6AL Ignition, MSD Blaster Coil

Carburetors: Dual Weber 44 IDF
idle jet: 60
main jet: 135
Air Corrector: 175
Emulsion tubes: F-11

My thought is that the main jet is too small as is the air corrector. Thoughts?

[/list]

[cn63bug]

One thing I would try is to increase your fuel pressure from 2 to 3 psi. With your setup, it would be better to run the 3 psi to make sure you're getting enough fuel. I'm sure other will chime in on this and your jet sizes.

[JimmyBaja]

[[email protected]]

that pump sucks. That regulator isn't (it's a restrictor). Replace both. I also recommend bumping the plugs to a heat range 6, 8 is quite cold.

60 idles are too rich, change to 55. Change mains to 145, and airs to 200.

That will get you close(r).
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[JimmyBaja]

[67rustavenger]

John makes no apologies for his posts. He just tell's it like it is. Don't be offended.
A Carter rotary FP is highly recommended. Get a Holley regulator downstream of the pump and you'll have a good setup.

Good Luck.
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[JimmyBaja]

[modok]

Carter makes a rotary pump that puts out 3-4 psi, internally regulated. No regulator needed.

I agree on jets. Most cases main 140-145, 55 idle. 175 air may be ok, but if you go up on the airs will need to use larger main also.
200 air, will probably need 150 main.

[74 Thing]

Get rid of that fuel pump and throw the regulator away like John suggested.

If you want to stay electric do an internet search for Carter GP60504. It pushes fuel so must be located near your gas tank and is set at 3 1/2lbs of pressure so you don't need a regulator. Rockauto has good prices. CB Performance sells it too.

Then check your float levels and follow the jetting advice John gives you. You can get jets from him that are orig jets that measure and flow the correct amount.

[JimmyBaja]

[Mikedrevguy]

That's the pump I'm running with 44s. Works well with no regulator.
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[mcmscott]

As some one with experiance with buggys and street cars here is my advise, loose the regulator, if that facet pump is the low pressure pump keep it. 1 grain of sand will stop a carter pump, when the same particle stops the facet a large screwdriver handle against it a couple times will get it going again, not the rotary. This is probably the only application where I would suggest this pump over the carter. And this is because I have been stuck in the dunes and desert with both of these pumps. Also you will not see a rotory pump used as a secondary in any limited desert cars, all Facets.
As far as your jetting I agree with most here.
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[JimmyBaja]

[[email protected]]

It's hard to give accurate advice with knowing the lift/duration of the cam and what size valves those heads have in them? Are they ported?
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Cylinder Head Reference Sheet

[JimmyBaja]

[JimmyBaja]

Thank you guys for all of the advice. I did a bunch of tweaks and the motor is now a smooth beast. Here is what I did:

MJ: 145
IJ: 60
Air: 200
Spark plugs: NGK D6EA
Valves adjusted
Carbs sync'd

No more mid range sputtering and feels more powerful.

[It's a play thing]

Idle seems on the high side, try 52-55's we will see what others have to say.
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I've been playing with my thing ever since I got it...

[modok]

yeah, usually 60 is too big, but not always, that's why I put "usually" in there.