ok i have a problem ive asked around a bit but like another answer from ya guys on 3rdGen. i got the q jet from a 73 chevy pickup with a 454(told i could run with the same jets..).. i swapped out my TPI for this carb set up.. the dizzy is from a non-CC 76 nova vacuum advance. and my intake is a edelbrock proformer..

i say its running rich n dies out fouling the plugs.. ive been running 8psi on it runs fine at idle n reving in netural.. but wen i get on it with a load on drive for about a mile it dies n wont start n ive killed my starter repeating this constant restarting..

should i consider rejettin??? or is it an ignition problem???

my engine is a 86 LB9

 

Drop the pressure down to 4-6 psi. 8 is too high.

 

ok kool ill do that

thanks

 

dropped the pressure to 5 psi.. and the plugs still foul i put new plugs n dropped ti to a whooping 3psi and the carb runs out on fuel in the bowl..

So some of my older friends told me to remove the choke plates off... so i did.. now runs fine and doesnt die with a load...

bot i got a question of will those plates removed result in anythin bad.. or more problems in the future???


thanks and happy newyears!!

 

Sounds like your choke wasn't operating properly either.

 

so how can i fix this should i keep them removed or should i fix the problem and put them back on??? the choke operated as follows....

closed when shut off....
primary opened when running
and secondary when full throttle

shouldnt it be that way anyway????

 

There is only one choke, on the primaries. The secondaries have the "air valve", which should be shut until engine demand opens them.

A '73 pickup most likely had a hot air choke. Does yours have a wire going to the choke thermostat? The choke should be closed when the engine is cold, open when warmed up. It's better having it operating properly for easier cold starts and better operation while warming up.

 

'75 was the first year for the electric choke on a Qjet, and that was Caddilac and some Chevy. '76+ for the rest. Before that was a hot air choke. Which one does yours have? Hot air choke will have a rod that goes down into the intake manifold on the passenger side, electric choke will have a single wire going to a black plastic cap on that side.

Does the choke open all the way? The choke plate should be completely vertical once the engine is warm.

Whats the primary jetting on that carb, do you know? Qjets are pretty forgiving that way, but who knows how much its been played with over 35 years...

 

ok ive been looking at pictures of q-jets on the e4me servie bulletine and i noticed my qjet has no thermastatic coil.... im not sure if it should have one and im sure it did not have any wires when i took it off the truck... im rebuilding it tonight jus so i know its been rebuilt in the past decade

 

It could be a divorced choke, but I thought those were gone by 73.

 

the choke opened all the way vertical once the car started and stayed open...

 

yes rejet the carb and you will also need some metering rods

get an electric choke and be done with it

 

ok took apart the qjet.. the jets had 74 on them.. and i noticed one of the air valve on the secondary was plugged.. what would yall recommend for jet size and metering rod/s?? (if i really have to change em dont want to but if it will make a reliable daily driver ill spend the money)

 

thats the black magic of it all

 

General rule of thumb with Holleys is to change two sizes at at time and drive it, see what happens. I don't see why that wouldn't apply to a Qjet as well. In your case, that would mean going from a 74 to a 72. Try it, see what it does. If it gets better, try going down to a 70 and see what its like, etc...

I think Edelbrock makes a Qjet tuning kit with jets, metering rods, etc. Its a pretty reasonable price.

 

i went to go check out the truck i took the qjet off of and it turns out this old carb used to have a rod that went into the manifold for the choke which is totally missing.. so i just went n disconnected the whole choke assembly till i buy a electric choke.. repaired the secondaries and i couldnt find any rejetting or metering rods around the area so i left them in hoping it was the defective choke

 

Does your performer intake have the provisions for the hot air choke setup (the one with the rod going down to the manifold)? Some do, and they are a good system... I'd just hook that up if it does.

 

yes my profomer has that little cover seal now but i cant find anyone or any where to find that choke setup

 

That's a divorced choke. Get the Edelbrock divorced choke kit that goes with the manifold.

 

ok will check into that