dual idf carbs spitting fuel up during sudden acceleration

[DRHSMITH]

hi all still having endless issues at idle if i push throttle wihtout air filters on a cloud of fuel vapour flies about three feet up unitl engine sucks it back down engine timing is bang on the amrkings and ignition timing from comutronix is timing lighted at 12 degrees start any ideas please would be gret

[fiatfactory]

.

[sptcoupe]

Sounds like some serious "stand off". I would also look at cam timing. What cams are you running? What jets are in the carbs?

[DRHSMITH]

cam timiing marks are bang on idk what cams are in it they are regrinded for mid range power the car cruises just fine over 500 k a weekend but i dont have the power that should be there , dual weber 45 , balanced crank high com pistons computronix ignition , lightened flywheel 2.5 psi fuel pressure, just under 10 000 k on new rebuilt engine but anything over half throttle the car doesnt have much of anything for power lots of low end torque but cant figure it out i ahve air fuel mix digital guages in exhaust with 120 mains goes way over rich when u hit the throttle

[sptcoupe]

Do you mean dual 44 IDFs or 45 DCOE side drafts?

Assuming they are IDFs, if it goes way rich at tip in, it could be the bleed backs are too big (the valve in the bottom of the fuel bowls. They run from 00 (no hole in it) to .80mm), and/or the pump jet (should be 45 or 50s). It will go rich for a moment on tip in, as the accelerator pump is feeding it extra gas to make the transition from the idle circuit to the main jet circuit. Is it just for a moment, or does it stay rich under WOT.

120 mains sounds lean. What emulsion tube (F11 or F9) and air corrector jets are you running? What size idle jets do you have? Are you sure the bores are balanced using the air corrector screws, and that the carbs are synched (using a synchrometer)?

Sounds like you have the right set up for the carbs, so it should work really well.

[DRHSMITH]

they are idf , i have 2 sets i wnet down too 115 mains still runs rich, the first set i have 125 mains 32 vent second 115 and 26 vent. both are not much differnt this engine before would absolutely fly then i burned out some rings . rebuilt it same a it was with a profeessional machinst who is accredited for racing engines . he told me would be about ten thousand k till igot the real horsepower out of it im about there now and have almost notihng . car is very reliable smoooth idle i drive it 500 k a weekend too my second job and back every weekend since may but there is just no horsepower past hafl throttle i have linakge that most do basically redo of orignal arm off of throttle lingae on valve cover going too a spring loaded screw center of both carbs for syching . i can sych the carbs perfect but every time i hit the throttle and come back down they change i have a good return spring i ahve an odler set of idf and a brand new one used the new linkage stuff nothing changes this fact rly frustratiing . carbs operate very easily wiht nothing attached feel smooth and no catching idk what too do

[DRHSMITH]

the guy who did spider engine origianally used the same set up for many other spiders so youd think i would be even close too a decent amount of power and as i stated the engine after the first break in was very fast until the rings went ive tried everythig many times that i could and nothing really makes much differnce

[fiatfactory]

.

[sptcoupe]

Agree with Fiatfactory. You should have 36 venturis to get max power from 44s. Also, agree re the timing. Having the marks line up doesn't matter if the crank pulley mark is not at DTC.

Stick a dial indicator into the number one bore spark plug hole. Get the piston to top dead center and check the crank pulley mark to see what it is indicating.