Alxrez

Hey guys looking for some carb wisdom.
I bought this carb off a older guy from Craig's list he seemed like an honest man and knew his stuff Had this nasty g body Buick. Anyways carb I got was a rebuilt holley street avenger either 650 or 750 I forget
I've installed it sounds like it wants to start but it doesn't.
I did the idle mixture screw reset where you bottom them out then turn them out 1 1/2 turns. Fuel bowls adjusted. Curb idle speed screw looks to be all the way screwed in. the spring that's on it is all the way compressed could this be why It won't start? Also is it really important that the secondary throttle plates aren't adjusted.??

92RS_Ttop

iTrader: (3)

First things first, put the distributor cap on and connect the spark plug wires. It won't run well without those

When you adjusted the idle mix screws, did you adjust all 4? In your pic it looks like the screw that's visible is screwed all the way in.

Next, I'd turn the curb idle screw out 1-2 turns. It shouldn't be bottomed out.

Then, open your choke plate about a 1/4" or so. It won't start easily, if at all, with that closed.

The secondaries need to be adjusted to a baseline open amount to start. If they are wide open, it could explain your problem. They only need to be opened a small amount. On mine, I started with the edge of the blades even with the edge of the baseplate. There is a small vacuum channel near them on the baseplate that they sorta block off as they open and close. You want the opening of that channel to look like a square, if that makes sense.

If it still won't start, open the primaries manually with the throttle lever and dump a small amount of gas down them. Not much, 6-8 ounces is plenty. If it starts and then dies after a few seconds, then you're not getting enough fuel through the carb.

Alxrez

Hahaha they're on now. Appreciate your help. However I'm havin an issue with the fuel level. It won't lower. The adjusting nut won't even lock on to the threads anymore. I empty as much fuel as I can by rocking the car. The try to lower the assembly but still the fuel is halfway.

Alxrez

I've also removed needle completely and cleaned

Alxrez

I've got it fixed I guess. Took bowls off and cleaned everything. Maro still won't start. when cranking. Only time it kind of wants to is when I spray starter fluid. Not even when I crack the throttle. Just with starter fluid. Ideas why?

Alxrez

also have choke adjusted like this. Look ok?

92RS_Ttop

iTrader: (3)

Choke plate angle looks good.

Dumb question, but you are pumping the gas pedal twice before trying to start it, right? Carb'd engines need those 2 pumps to prime the engine with some gas to start, unlike fuel injected cars. Think of the primer bulb on your lawn mower. Pump the gas pedal 4-5 times, then WITHOUT cranking it, open the throttles blades manually and see if the inside of the intake is wet. You should see evidence of gas in the intake manifold through the blades. If not, your not getting fuel through the carb and into the intake.

What is your fuel pressure at?

Are you sure the plug wires are going to the correct cylinders, in the correct firing order?

Have you tried adjusting the timing slightly one way or the other? If the distributor is too far off one way or the other, it can cause the problems you are seeing. In your fist pic, it looks like the rotor is already past where the cap terminal for #1 cylinder usually is. I'd suggest turning the engine by hand with the distributor installed til you get to TDC and check the rotor position.

Alxrez

Thanks for your reply. I got a chance to work on it today.
I'm not pump the had pedal because I really want to avoid flooding it. I've done before. So I've only been using starter fluid. But carb dose squirt out fuel as it should


Today a threw in a fresh set of plugs. Triple checks wires are going to correct cylinder.

Also I know timing is correct as I used a piston stop on cly#1 on compression stroke the rotated backwards and divided between the two marks to find true top dead.

I was getting some backfire out the carb but rotated distributor until it stopped happening.

I was able to get it to run for about 3 sec. By continuously spraying starting fluid.

Everything points to the carb I guess :/

-=Z28=-

iTrader: (3)

Sounds like your distributor is off by 180 deg to me.... what engine is in the car? 650/750 cfm is a big carb even for a 350..... rememer bigger isnt always better...

Alxrez

Well triple checked timing. I used to the piston stop tool. Because I wasn't sure if timing mark on crank pulley was correct but it was. Block has been bored. It's a 355. 11.1 compression supposedly.

steve87ta

iTrader: (4)

Still seems to be 180 off to me. The piston will still be at tdc. Maybe pull a valve cover to make sure both valves are closed.

92RS_Ttop

iTrader: (3)

I have to agree with steve87ta. That would also explain the backfiring through the carb.

jwfirebird

iTrader: (2)

its not going to start set at 0, 350 with a decent cam and compression is going to be around 20. set it to 20-30 before for initial start and tweak it down to what it likes. regardless of what people say on here the 750 holley is fine for a healthy 350

jwfirebird

iTrader: (2)

also starting fluid is almost never a good idea, its a good way to blow stuff up. if it wont run you have a problem that needs fixed. no engine needs starting fluid to start. you wont even see any on my shelf. have a few souvenir pistons on my shelf with big holes i show to people to get them to stop and see whats wrong.

-=Z28=-

iTrader: (3)

I did not say 750 was TOO big of a carb for a 350. there are many factors. Lots of people think just by slapping a 750cfm on they will have a hp increase. I have a 383 built pretty decent, and my 750 is almost too big for it. So it really depends on what is on your build sheet engine wise. If it can suck in and burn all the fuel properly...

-=Z28=-

iTrader: (3)

bump the engine over till you see the timing mark coming around. have someone put there finger over the number 1 cylinder hole to make sure the piston is coming up. when it is tdc, point your rotor on the distributor towards the #1 cylinder as you slide it in you may have to bump the motor to line up the gears on the cam and distributor. thats how i was taught and it always works. granted i had to fart around with it till i got good. There are many tricks. one helpful trick is always remember your steps that you took. Another good way is to you-tube it. tons of videos. good luck and let me know if you got her running.

jwfirebird

iTrader: (2)

if you set it to tdc and put it at the #1 terminal, thats setting it at 0 degrees, wont run that way most times. especially a higher performance engine. have to set it with the cyl at tdc and a bit before number 1 (counter-clockwise on a sbc)

-=Z28=-

iTrader: (3)

I agree, but it should do something. thats how i do mine for a base and adjust from there when its running. I dont get why it wont even run... I once had my dist 180 deg off and the car ran. no power but it ran. Did he even pull the dist? I dont know why he woulda for just a carb swap.

Alxrez

I hate a dead thread where OP never posts results.

But I finally got it runing all timing was right. Plugs where good. The holley carb that was on there was the prob not sure why. Although I did have fuel towards the left side of gasket when I pulled it off. Slapped on a edelbrock 1406. She was alive .) thanks for your help guys