e85 Holley incurable stumble

[Ks Fats]

EVL,
Perplexing for sure. I'd think an ifr in the .035-.038 range should be sufficient. On my methanol stuff I'm usually between.028 and .031 on the high side a/b so should be in range. You earlier mentioned a stuck check bullet under the secondary squirter, I've seen the screw bottom out on those at times (or at least restrict upward travel). Try a nylon float bowl screw under the rear squirter as a gasket to see if that helps.

[EVL253]

currently the rear has no needle under the rear squirter its working properly & didnt make a difference

[Ks Fats]

No delay in delivery without the check needle?

[pamotorman]

currently the rear has no needle under the rear squirter its working properly & didnt make a difference

unless the metering body has a check ball in the squirter passage the fuel in the squirter passage will flow back into the pump cavity without the needle

[Ks Fats]

That was my thought; the level in the nozzle delivery passage would lower to at least the level of fuel in the float bowl leaving air above it. Has to delay the delivery.

[EVL253]

no delay fuel is there as soon as u touch the throttle. even bump the pump lever it squirts.
this issue existed long before this needle issue

[Ks Fats]

Guess that eliminates that variable; earlier in this deal someone mentioned swapping blocks primary to secondary etc. I take it the problem did not follow the block?

[EVL253]

no hasnt followed the block turned whole carb around as well absolutely nothing makes a difference.
im really thinking although 600cfm on gas on 257 cubes was ok its to much on thicker E85. as this carb on gas would 60ft 1.8 every time & bang on et & mph each sector. now ive only got 1 run easing into throttle to 60ft at 1.87 yes run had best mph & et but stumble is annoying

[Ks Fats]

Still got the 1 &9/16 base on it?

[EVL253]

650 base 4777 list whatever size that is with a 600 4776 body. same as it had on gas. boosters n blocks been changed for E85

[Ks Fats]

That base is 1&11/16; I've used that combination on smaller engines also but never in that c.i.d range, mostly 311 to 331 circle track apps. I used a modified straight leg in mine and that seemed to bring the egt's closer together. Even with the difference in specific gravity It should be possible to find a combination it liked I'd think; other than switching back to the 1&9/16 base plate you have about exhausted everything in between. If I remember correctly I couldn't drill the straight booster feed much larger than .159 to keep from breaking through the cross-over bar but it had adequate flow to feed engines in that range. Sorry for all of the questions and the lack of help...

[EVL253]

all good mate never know what someone might come up with

[levisnteeshirt]

I would drill holes in the throttle plates, start at 1/16 and go up till it will idle with the primary blades all the way shut, drill the hole the idle mix screw goes into to .070 , this should require the idle mix screws to provide all idle fuel, and when the transfers come open , that fuel will be there,

[naukkis79]

E85 will ignite fine with very lean AFR, so total tumble usually means too rich afr.

Which kind of intake manifold that setup have? Some manifolds have ribs under carb to evaporate fuel drops but with E85 you absolutely don't want them as there's place for fuel to stay. And if there is a bathtub of E85 under secondary throat it will flood engine when secondaries open.

[EVL253]

2 different manifolds tried a single & dual plane no ribs in either. lean or rich doesnt matter nor does it seem the acc pump setup.
carb has gone back to the builder currently