i just swapped from tb to qj. it idles great fp stays at 5 psi. whwn i stomp it it bogs big time and does not want to go. is there any tips i could try. i am running a mallory 4309 and the qj i used was off a 305. plus i now have the performer rpm and i inch spacer/adapter that is open in the middle. i have a friend that is going to look at it too. it also got stuck at like 3500 rpms when i floored it and i had to turn off the car to get the idle down.

 

Could you describe the bog in more detail? Does it take off and then go flat? Does it just bog instantly and then recover and haul butt? Does it bog and stay bogged? What's it like?

 

Is your Air Valve opening too early? Mine did that for about a week, then adjusted the tension and it went away.

Check it in your driveway.. just let the engine warm up a bit, then (by hand) yank open the throttle and watch the AV to see if it starts to open. It should NOT open at all with no load on the engine.

BTW.. for a typical 350, the tension screw should be set somewere from 3/4 to 7/8 of a turn.

 

Q-jet has great big secondary's. Sounds like your going lean on wide open throttle. Slow down air valve door and go biger on the squiters and accelerator pump shot (hole closest to the fulcrum point).

 

WHEN I STOMP IT THE CAR DIES THEN SLOWLY SPEEDS UP. its not very powerful either... my tb was way faster!!! but i know once i get it dialed in the carb will take the cake!! i think i am going to change the 2ndary metering rods... any other ideas?

 

Adjust the tension first. Don't dink with the rods until after you get it to a point where it doesn't just flop open and let in so much air that the engine can't use it all. That's what creates the bog.

Set the air valve tension to about 3/4 turn, and go from there. Adjust it in 1/8 turn increments from that point until you get no bog. No amount of twiddling with the rods will help until you get the AV's opening rate controlled.

I seem to recall telling you about this once before, in a related post where you asked about the "size" of the Q-Jet.... this is exactly what I was referring to.

 

were can i find the adjustment??? i know where the 2 screws on the front are and also the idle screw but where do i adjust the av? i'm still new at the qjet thing. i downloaded alot of stuff about this thing, so hopefully someof it will help. thanks for the tip i will try to get it right. i forgot that you told me that before... sorry
ive got several people telling me diffrent things to do. one of them said i need to change the power valve. he said the plunger in it might be bad??? also the 2ndaries got stuck open a couple of times... so i had to drive around at about 4000rpms till i could pull over and tap on them to come loose.

 

found an article on how to adjust it... also i don't know if anyone noticed b4 but i said i had an open spacer/adaptoer in between the carb and manifold will this affect the secondaries some? and if i remember correctly when i was in the driveway and i pulled on the throttle the av did not open at all. should i still play with the setting?

 

Lose the spacer, in all likelihood it's not helping. After you get the carb working right, then you can try putting it back, as a tuning tool. Until then, it's an extra variable you don't need.

The AV should not open if the engine isn't under a heavy load. Sitting in the driveway and just winging the throttle should not open it.

Adjust the AV tension to 3/4 turn and go from there. Start at the beginning, verify that the carb is put together right, get the carb to work correctly before trying to tune it. You can't tune an improperly assembled carb.

 

well i can't loose the spacer remember i said spacer/adapter...
the manifold is a square bore and the carb is spreadbore... the adaptor is the only way i could get it on there. plus the carb is a remaned one and it was running fine b4 it was yanked but it has been sitting for about 2 years. so my buddy here said that he thought the ?powervalve?... or plunger seal could be dry rotted... because it was sitting without fuel in it. also do i have to loosen any screws on the bottmom to take the top off, or just the screws on top?

 

It's unlikely that anything is dried out to cause that. Q-Jets aren't as prone to that problem as some other carbs. *cough*Holleys*cough*

All of the air horn screws are on the top. But, you don't have to disturb that to make the adjustment in question.

The adapter will tend to make the carb run lean, because it will allow the 2 secondaries to share the individual cylinder pulses instead of forcing them to flow only through their own barrel. It will exaggerate whatever "bog" you might already have. If you can figure out a way to divide it down the middle with something that will for sure not get sucked into the engine, it will help.

 

I CAN PUT another spacer on with the adaptor that has a divider in it and that will divide it some more...??? i could get one of those plastic ones .

 

It would need to be something that divides the adapter in half, so that it isolates the 2 sides of the carb.... you might want to look into getting a 4-holer

 

2 YEARS???? That accelerator pump Will dry up and or shrink. Get yourself a re-build kit and replace it, or get someone to do it for you!! Your spacer/ adapter if less than 1" thick shouldn't bother that Quadro! I've put a few on with no problems. Sitting on the "shelf" for 2 yrs dries everything up! To mention a few, fuel float hinges, Inlet valve tips, Base to body gaskets, and even spiders like to lay egg's in them anywhere they can fit their little ***'s in!! believe me, I've been there! after you get it back together use a little WD-40 on all the moving parts like throttle rods, choke door, secondary air door, any thing on the outside that moves.

 

Sorry bout that, I read the posts again and didn't catch that Quad to 4 hole part. The adapter only works well with an open plenium not a four hole. U need to change manifolds or trash the Quad. The 4 hole under the spacer is a big obstruction to air flow!

 

THERE IS NO 4 HOLE...??? the manifold is a square bore performer rpm and the spacer is open its one big hole. and i messed with the av last night and something is not right with it because it never just flopped open. or closed it was like something wasn't attatched right...??? it drove a little better yesterday but it sucked this morning when it was real cold!!!

 

a friend of mine looked at the carb and said it looks like a piece is missing. there are 2 screw holes on the back passenger side of the carb and it looks like something goes there. plus when i crank it the vacumn can does not suck the av closed it is stuck open.

 

NEWS FLASH I LOOKED AT SOME PICS ON THE NET AND I AM MISSING THE REAR LOWER VAC CANNISTER AND LINKAGE... OH WELL I WILL HAVE A HOLLEY DP IN A COUPLE OF WEEKS...

 

Thats your problem! If I was looking at it with my own eye's I'd know that Huh? You might still put a spacer on it though, Holley's hate heat!

 

CAN SOMEONE SEND ME A GOOD CLOSE UP OF HOW the linkage conects...??? please

 

92rsv8! If U go down to your local pull it yourself junk yard, not only will U be able to see the part, U can stuff it in your pocket and take it home W-U ! I was at a local yard last week-end and I'll bet I saw 10 or 15 of them. Nobody wants them because they sit in the weather with the hoods up but that doesnt mean the parts on them are no good. Even if you don't use the whole thing, the parts are worth the 10-15$'s and a few minutes it takes to pull them yourself. A lot of times U can take a piece of hose (clean!) stick it on the diaphram and suck (for lack of a better word) and check the diaphram to make sure it works.

 

I HAVE THE PARTS I GOT THEM FROM A FRIEND...

 

KEWL, Hope everything works for ya. Let us know!!

 

well the parts did not work but i went to az and bought the choke pullpff valve for 12 bucks and it works pretty good now. the only problem is i have to figure out how to adjust the av because there is 0 tension on it!!! i guess the spring on it is messed up or unwound??? i will do a search and see if i can find out how to reset the spring tension. it doesn't bog like it did b4 but it gurgles a little and has a very slight bog then it goes much faster than it did b4. thanks for all the info. also will the 70 series 2ndary rods work with the 170 series carb?

 

oh also my car is deiseling . i have the timing set at 8* advanced when i cut it off it stays running for about 5 seconds...

 

Don't let it keep doing that! Try shutting it off in gear. Really hard on Engine. if you have to drive it, disable secondarys and drive on primarys till you get it fixed.:nono: or untill you get the holley.

 

Hey, I went over to a friends house tonight and the subject of your problem came up, said he had an old one in the garage so we went out and looked at it. You have to remember, I'm 53 yrs. and it's been a long time but after looking at it some old memories came back. The point is, some people actualy tried to make the secondary's open manualy. It kind of worked half a$$ but to keep it from bogging they had to put so much tension on the air door it opened real slow. Check to see if there is a linkage arm connected the the secondary's that force the secondary's open. Usually found where the vacuum can connects to the secondary arm. If there isn't one U can take a piece of wire and put it through the hole and tie it somewhere to keep the secondary's from opening. It should keep it from bogging and dieseling so it will be driveable untill you either get the right parts or another carb. I'm about out of ideas from here. hope to help!

 

well the part i got from az works just fine the av's don't open while i am in the drive way.... but i think the spring tension needs to be reset on the av and i tried to search for that info but could not find it! i had a truck a few years back and i had a webber carb on it. we had it set too rich and it deiseled like crazy and fould plugs every 5 or 6thousand miles. i turned it off in gear and pinggggg it broke the clutch so i had to get a new one!

 

Turned it off and eased the clutch out and it broke? Damit! I'll bet you were pi$$ed! What broke? the P-plate?

 

i think the springs broke its beed about 5 years so i can't say for sure but it would not go in gear at all??? yup i was mad!!! i paid 300 for the dual webber 38mm barrels and another 200 for aa beefier clutch!!