Problems with reman Q-Jet: round two

[SilveradoDude]

Originally Posted by cadillac_al

After all that, your throttle plates should be closed pretty tight. I wonder if the secondaries are sticking open a little. I had a couple that the secondaries would hang up. I also had a couple vehicles that I couldn't get idled down and I resorted to ported vacuum for the distributor. Those could have been vacuum leaks that I couldn't find.

How do I check the secondaries to see if they are hanging?

[geezer#99]

Originally Posted by SilveradoDude

Standard FelPro gasket. (new) I sprayed carb cleaner around the gasket and didn't receive any rise in RPM's.

That means nothing to me.
Is it a thin paper type (bad)or 1/4 inch thick (good)insulating type gasket.

[SilveradoDude]

Originally Posted by geezer#99

That means nothing to me.
Is it a thin paper type (bad)or 1/4 inch thick (good)insulating type gasket.

Thick.

[akart]

Originally Posted by SilveradoDude

Ok, I got a new reman Q-Jet.
It runs a lot better out of the box than the last one but it still needs some adjustments I just don't know which ones.

symptoms.
- idling way too high
- dieseling
- white smoke

What adjustments do I need to do to get this carb running right?

(85 C10 305 - 84 ignition)

I bought a reman "Jet" Quad from Summit the throttle shaft was loose, which will leak air,they said it was bushed but it was not and most of the screws were boogered up like it was assembled by a crack head. Summit was very nice and refunded my money. Bought an Edelbrock 1405 600 cfm manual choke and it ran fine right out of the box. I changed the jets and needles as per recommendations on this forum as they are rich out of the box also bought the Eldebrock fuel pump for correct pressure and a 1" fiber spacer to keepit cool. I understand this carb and I am buying another. Getting 12.5 MPG and I think I can improve that. 3 years and counting.

[SilveradoDude]

Originally Posted by akart

I bought a reman "Jet" Quad from Summit the throttle shaft was loose, which will leak air,they said it was bushed but it was not and most of the screws were boogered up like it was assembled by a crack head. Summit was very nice and refunded my money. Bought an Edelbrock 1405 600 cfm manual choke and it ran fine right out of the box. I changed the jets and needles as per recommendations on this forum as they are rich out of the box also bought the Eldebrock furl pump for correct pressure and a 1" fiber spacer to keepit cool. I understand this carb and I am buying another. Getting 12.5 MPG and I think I can improve that. 3 years and counting.

Yeah, no. I have no idea what you are getting at other than trying to suggest that an Edelbrock is a superior carb to a Q-Jet which is not the case, especially if I have to buy a spacer and a fuel pump just to get it to work.

[cadillac_al]

[QUOTE=SilveradoDude;8418206]How do I check the secondaries to see if they are hanging?[/QUOTE

Just look at your linkage and watch the secondary linkage to see if it is returning all the way. I have had secondaries get hung up on the intake manifold or the gasket and not close all the way. The linkage itself can get a little sticky too. Is that thing still idling high? If you get those throttle plates closed up tight and it still idles high it must have a vacuum leak somewhere. I would still try the ported vacuum as a work around.

[zac]

In the third picture I posted I’m pointing the blade of a small screwdriver at the part of the linkage on the drivers side that should be touching the end of the curb idle screw when the engine is warm and is completely off the fast idle cam. If they don’t touch, you have no ability to adjust the idle speed. Is that the case, and does the idle increase when you turn that screw clockwise and decrease when you turn it counter clockwise?

[akart]

Originally Posted by SilveradoDude

Yeah, no. I have no idea what you are getting at other than trying to suggest that an Edelbrock is a superior carb to a Q-Jet which is not the case, especially if I have to buy a spacer and a fuel pump just to get it to work.

I apologize for bringing up Edelbrock on this Q Jet thread. I think I will try a Q Jet just for fun. Must be something to them as many swear by them and maybe I am missing something. But will buy from SMI which my research says they are the best or close to it. They're price is like 500.00 plus ship but I don't think there is any fiddling around involved.
Good luck to you w/your Q Jet.

[SilveradoDude]

Originally Posted by zac

In the third picture I posted I’m pointing the blade of a small screwdriver at the part of the linkage on the drivers side that should be touching the end of the curb idle screw when the engine is warm and is completely off the fast idle cam. If they don’t touch, you have no ability to adjust the idle speed. Is that the case, and does the idle increase when you turn that screw clockwise and decrease when you turn it counter clockwise?

That is the case when warm the curb idle DOES NOT touch the cam. Yes it does increase and decrease when the screw is able to touch the cam. Also, 2 more things. I put a vacuum gauge on the truck at the intake and I am getting a sold 14 inches which seems a bit low to me. As I understand 22 to 16 inches is normal. Also, I have disconnected the cruise control linkage from the carb as it seemed to be pulling the accelerator back a little bit and i don't use it anyway.

[zac]

I am very confused. The fast idle cam is on the passenger side. The screw to adjust it is behind the choke housing, below the front choke pull off and the fuel line. The curb idle screw is on the opposite side, inboard of where you hook up the throttle linkage and towards the front of the carb. They are two different screws. The curb idle screw never touches the fast idle cam and is on the opposite side. I’m trying to be sure we are talking about the same thing.

[Desert1957]

Try this pic

[Desert1957]

[SilveradoDude]

Originally Posted by zac

I am very confused. The fast idle cam is on the passenger side. The screw to adjust it is behind the choke housing, below the front choke pull off and the fuel line. The curb idle screw is on the opposite side, inboard of where you hook up the throttle linkage and towards the front of the carb. They are two different screws. The curb idle screw never touches the fast idle cam and is on the opposite side. I’m trying to be sure we are talking about the same thing.

I was talking about CURB IDLE, driver side. THere is a cam on that side as well.

[DoubleDubya]

I too was unable to lower my idle even when the curb idle screw was not touching the cam. Turned out it was the electric fuel pump (I have a '98 Vortec block so no mechanical pump) over pressuring the float. I replaced the pump and solved the idle problem. Could your fuel pump be doing the same or is the problem with the float level?

[SilveradoDude]

Originally Posted by DoubleDubya

I too was unable to lower my idle even when the curb idle screw was not touching the cam. Turned out it was the electric fuel pump (I have a '98 Vortec block so no mechanical pump) over pressuring the float. I replaced the pump and solved the idle problem. Could your fuel pump be doing the same or is the problem with the float level?

I have the manual OEM mechanical fuel pump it seems to work fine.

[SilveradoDude]

Ok I think I have her running pretty good right now. Here is what I did and here are the specs.

I dealt with any and all vacuum leaks (nothing big here)
I ran the vacuum advance from the rear T
And I adjusted the fast idle cam back up as it was running a little low.
I adjusted the timing back to where it was.

Timing: 6 degrees BTC from 4
fast idle cam: adjusted half a turn clockwise
RPM in P is low 700's
RPM in drive mid 500's
Solid 15 inches vacuum reading

No smoke, no rough idle, no dieseling

The last adjustment that I have left is the transmission kickdown. I have been having trouble depressing that button for the cable.

[Jaysonb]

Once the engine is warmed up, if you set your timing at about 12 btdc, your engine will be way happier, it will increase your idle vacuum, and be much more responsive, and get better mpg. Then with the engine warm, fine tune your idle mixture screws with a vacuum gauge hooked up to manifold vacuum, adjust to untill you get the highest vacuum reading.