weber carbs and fuel pressure

[t_mertz]

Hey i see your online. ok so ive been trying to read your post on the carb settings. So do you or wny one know the basic jet settings for a 38 on a z24. I picked up a used one but im sure the jets are huge as it was a high performance kit for a 256 6cyl jeep. Idk i just cant figure all this out.

[PEZi]

well i can't be sure what's in it without knowing what the previous owner did

i have a weber 38 however... and it is all stock still as sent by weber meaning 145 mains and it runs fine with the mods i have done... if you don't have any mods then it will be too big of a carb for Z24 but its not hard to get it breathing a little better in order to take the carb

[t_mertz]

Ive just got a header and vacuume lines. Plugged. Straigh exhaust dumped in front of rear wheel. This is an 89 convertion back to carb ive seen many ppl swap 38 on you think the header is enough to get things moving faster. Its a real pacesetter. Idk after i get all this set up and. running i got a t25 off my old 240 to hook up a down draft setup. I just have no clue what my carbs got in it and want to try and start with what like weber shippes the 38 720 kits jetted to

[PEZi]

the kits don't come jetted any different from one to the next (as far as i know)

for a 38 they should all have 145 mains... which is just fine for the 720 but the idle jets and air corrector may need changing

you won't really know whats in it without taking it apart and measuring though

[t_mertz]

I have no clue what the prev. owner did to the carb. Thays why i jusy wanted to rejet the whole thing. so just main jets to run this im sorry im still learning alot about the carbs trying to find what weber ships out the 720 z24 kits at. Is that all thats different for diff applications is the mains and then just adjust the idle screw? Ill probly just disconect the elec choke for now to get it running good warm. Idk from others they say its best to keep from reving high before oil press comes up.

[PEZi]

the kits don't come jetted any different from one to the next (as far as i know)

for a 38 they should all have 145 mains... which is just fine for the 720 but the idle jets and air corrector may need changing

you won't really know whats in it without taking it apart and measuring though

[Largebudda]

Have read through the Post and there is tons of good info. I do have a question about a problem that has me stumped.

Carb - weber 38
Remain fuel pump
(no fpr at the time of problem)
timing was dead on

After fixing a few vacum leaks in the process of swapping carbs and remembering to give vaccum to the Timing advance I was able to get the truck to run at idle but it was an extremely high idle. Set the carb as low as I could and idle was fine but when taking off the truck would need to be rev'd to a higher rpm to prevent it from stalling. Anyone got some ideas?

Am in the middle of swapping to a lower mileage Z24 and will have it complete byt Sunday afternoon. Swapping tons of parts for new or like new.

[PEZi]

i had the same problem... its going to partially be getting the right fuel pressure, and partially fine tuning the carb at idle... it took me a few tries to get it where it wouldn't do that any more

[Largebudda]

Due to some cold weather I have been a bit delayed on the the install of the engine but it is up and running now.

Carb is working great but when pedel is put to the floor the motor bogs down, when released the engine's RPMs climb shortly then level out. Was wondering if you could shed some light on the issue.

Distributor is pulling vacum from below the butterfy.
All other vacum except for the brake booster is plugged.


Budda

[synack7350]

I actually ordered some bigger idle jets for mine as the stock .60's I'm have to crank the mixture out on. got some .70's and .80's. should be here by next week. I'll let you know how that works out. for fuel pressure my electric pump is delivering a steady 3psi without a return line. the spectre fuel pressure regulators suck (mine failed after 15 minutes and wide open constricted pressure to 2 psi) further more mr. gasket fuel pressure gauges suck. the spectre gauge actually works, so I'd recommend it for a cheap gauge. for fuel pumps the rotary vane style carter is recommended to be used without a regulator, so if I were to have to replace mine thats probably what I'd go with. I would avoid the solenoid style 1 they are noisy and 2 your pressure is going to vary. I'm an electrician so if yall have electrical questions I'm here all week.

[flinterman2000]

Carb is working great but when pedel is put to the floor the motor bogs down, when released the engine's RPMs climb shortly then level out. Was wondering if you could shed some light on the issue.

Budda

From all I've read, it looks like your problem is still timing. With the removal of all unnecessary vacuum lines, the timing usually goes off a little. It looks like yours is too advanced. You will need to address jets and such for the carb also.

[synack7350]

I've been all over the range from lean to rich with the 32/36, it sounds like you are just running a little rich, when I was running on the lean side the thing would just rock with the secondaries open (sounds awesome too like "sucking the pavement off the road"), but on the rich side (which is actually right for my idle) it does the same thing with the secondaries open, I'm changing to bigger idler jets so maybe I can fine tune the mix better and I'll post up if the issue with the secondaries improve as well.