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79' GMC C15 - Spruce Caboose

79 GMC 1500
Okay so I must not have measured the float height properly. It stated that you should use one finger to hold the bar that's inserted through the float, and the other to push down on the float and needle valve until it sits in its guide. It said apply slight pressure. I tried to push it down until it was just seated? That's probably where I messed it all up.

When you say diaphragm you mean the rubber round part with the spring inside it that sits around the bottom of the pump
?
Meaning the fuel pump may not be keeping the fuel above itself, slowly leaking backwards towards the tank
 
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Okay so I must not have measured the float height properly. It stated that you should use one finger to hold the bar that's inserted through the float, and the other to push down on the float and needle valve until it sits in its guide. It said apply slight pressure. I tried to push it down until it was just seated? That's probably where I messed it all up.

When you say diaphragm you mean the rubber round part with the spring inside it that sits around the bottom of the pump
?
I can’t help you with the magic measure stick. I stick my finger on the needle to hold it down, then adjust the float by eye

remember, the bowl doesn’t have to drain complete, just enough that that accel pump doesn’t have fuel above the lip that’s cut out to flow the fuel into the cup. It the bowl losses fuel, the accel pump is also draining
 
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Meaning the fuel pump may not be keeping the fuel above itself, slowly leaking backwards towards the tank

Ok, thanks for the knowledge. I'm still in carburetor kindergarden. I miss my tbi, but not really. So the carbs coming off again to re set the float height... Fuuuuunnnn
 
Well with this whole covid thing I ended up getting a day off and went into the quadrajet again. This time I also changed the accelerator pump since the kit I got came with a new one, and after being in this thing twice already, I figured maybe this will be the last time.. for awhile.. maybe.. ****... Haha

Anyway I fiddled with the float for awhile measuring the 15/32 height over, and over, and from this way and that way,a settled on having it set right, and from 3/16s back from float edge. The epoxy on the well plugs held up n it seemed fine, so I just cleaned it some more and then re assembled. IMG_20200327_112810.jpg IMG_20200327_165635.jpg IMG_20200327_165645.jpg

I cranked it over for about 15 seconds to put some fuel in the bowl , stopped and then pumped it twice and she fired up. After applying some gas pedal for a few seconds it idled fine. All seems well, but I'll go out in the morning and see if there is a wet gasket and an empty bowl..

There is a small amount of the gasket that got wet right away at the front of the carb but as it ran for awhile, it didn't get worse, soooo... I dunno ha
 
It's all good Dean, thanks ! I got it narrowed down to 2 paint codes so I'll get a can of each made, spray and eliminate the off one.

The two rear quarters, inner and outer cab corners are ready for pick up, and I found a straight hood also I'll be picking up in the next few days. Looks like I'll have a few days off so I can start sanding the front fenders and hood down, as well as painting the front bumper and wheels also.
 
So it seems it's still leaking somewhere.. but on a good note it runs the best it ever has once it's fired up.. I think I'll call that good for now. The air horn is quite warped and I doubt that's the reason its leaking but I have some friends with some carbs laying around, maybe I'll just throw a different one on there, although I'll probably just get different problems with one of those haha.

Started to dig into one of the fenders I got and the one I knew had some body work done to it turned out to be pretty poor, aaaannd the other has Bondo in it too that I've discovered.

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I'm going to pick up my cab corners and hood tomorrow, and I think that guy will have some fenders so hopefully I can get a set that'll take a lot less work.

Going to tackle painting the bumper on the next sunny day but tackled the mirrors today, being cooped up n some sun shining through.

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They definitely aren't perfect and even painted over one of the four screws on the back but it was fun anyway, and they look way better than rusty buckets of water... (They will get replaced with the blazer style, once I find one to complete my set anyway )

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Picked up some parts today to hoard for the rust repair. The guy that bought my blazer gave me a credit towards him (on top of the cash) since he owns a shop and hoards some Chevy stuff. The blazer keeps on giving!

Picked up the outter and inner cab corners. Don't think I'll need the inners but better have them and not need them. Got a rear quarter patch he had laying around, he ordered me one for the other side as well.

Got a front passemger side fender to replace the one who's body line is shaped with bondo.

Also picked up a hood. Mine has rust going through the front in a few spots, is bent and some dings in it. This one's pretty rust free ( nothing that can't be cleaned off ) and one small ding.

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Also took the carb apart again... Set the float height this time by blowing on the fuel entry passage, and pushing down on the needle until it seats and refuses air, then using that as my benchmark for measuring rather than applying ( solve for X ) amount of pressure... set it a 1/16 or so below 15/32.

If the fuel drains out this time, I'm fixing it with fire and nuns.
 
I don't understand how they rust at the front of the hood.
 
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I don't understand how they rust at the front of the hood.
Moisture from the inside.
I have seen it, just the front.
The rest all perfect.
The newer 81-91 design doesn't have this problem
 
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Also took the carb apart again... Set the float height this time by blowing on the fuel entry passage, and pushing down on the needle until it seats and refuses air, then using that as my benchmark for measuring rather than applying ( solve for X ) amount of pressure... set it a 1/16 or so below 15/32.

If the fuel drains out this time, I'm fixing it with fire and nuns.

Right on Nick!


Hopefully that works out. If it doesn’t... I had a 1980 montycarlo that I got cheep from a buddy that just wouldn’t run right I played with that quad for weeks... kept flooding out! It had a brand new fuel pump on the block installed by a shop before I got the car from my friend. I just could not get that carb to work... After thinking about it for weeks I looked at that brand new fuel pump. :thinking:
I took it off and replaced it with the greasyest old pump I had off a truck I bought that hadn’t ran in god only knows how long? Car ran perfect after that, never flooded again. I drove it for about a year after that before I sold it.

Something to think about!?
 
Right on Nick!


Hopefully that works out. If it doesn’t... I had a 1980 montycarlo that I got cheep from a buddy that just wouldn’t run right I played with that quad for weeks... kept flooding out! It had a brand new fuel pump on the block installed by a shop before I got the car from my friend. I just could not get that carb to work... After thinking about it for weeks I looked at that brand new fuel pump. :thinking:
I took it off and replaced it with the greasyest old pump I had off a truck I bought that hadn’t ran in god only knows how long? Car ran perfect after that, never flooded again. I drove it for about a year after that before I sold it.

Something to think about!?
Fuel pressure too high
 
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Right on Nick!


Hopefully that works out. If it doesn’t... I had a 1980 montycarlo that I got cheep from a buddy that just wouldn’t run right I played with that quad for weeks... kept flooding out! It had a brand new fuel pump on the block installed by a shop before I got the car from my friend. I just could not get that carb to work... After thinking about it for weeks I looked at that brand new fuel pump. :thinking:
I took it off and replaced it with the greasyest old pump I had off a truck I bought that hadn’t ran in god only knows how long? Car ran perfect after that, never flooded again. I drove it for about a year after that before I sold it.

Something to think about!?

It still flooded out.. :weapon39:

This time i triple checked everything. Even took all my jb weld off the well plugs, and re did the jb weld. The air horn is still warped haha no chaning that, it all seems good, but just took it all apart, then back together one last time.. Fuel filter has a check valve in it, although it doesnt seem like the most secure fit, im sure its supposed to work ha, theres a spring after the filter, the needle and seat are seating, theres no leak around the seats metal washer ring, the float actually floats, pivot pin in fine, needle valve isnt hooked into the float, float height is set at 17/32 , and no air is passing the needle valve at that height...

Ive read many forums, and so many people have had this issue and of course with that, theres 1000 fixes and opinions.. from heat riser fuel evaporation, to well plugs that should never leak after rochester revised them in 69, to air leaks causing a leak down BUT if its not the well plugs, it has to be the needle valve not closing for fuel to get out of the bowl.. right haha? I feel like im going a little qjet crazy, over reading all this jargen on the interweb since a lot of it hasnt come from here..:dunno:

I did notice when i took the fuel line ( hard line from pump to carb ) off, there was never much fuel leaking out, if any at all. It got me to thinking that even if the bowl leaks somehow, that line should be full, so maybe the diaphram is shot as well... Took a closer look at the lines going into the pump from the tank and they were wet at the ends. Took both off, a bit of fuel came out of one, and more fuel came out of the other, but both were wet, the hose clamps were shotty ,and the ends all weathered and old. I made sure i had enough slack and cut the lines back to fresh ( since the hose seems to be in good shape ) and re did the hose clamps. Am i right in thinking if air was getting in, it would release the vacuum in the line and the fuel would drain back to the tank, which isnt my issue. BUT if i could atleast get fuel to be right at the bowl entry, then filling it probably wouldnt take so long as the bowl doesnt hold much fuel. I am tempted to get a new fuel pump as this seems to be the original.. ( its a carter) pump on here, and ac delco has them cheap enough (35$) that trying to find a diaphram kit, seems pointless. I could test it with a vacuum gauge as well to see if its operating at its PSI rating.

I am really trying to elminate the throwing parts at problems side of me, since i want to learn more, but ill need the truck soon as my daily to work and a 35 dollar part isnt the worst idea to help solve some of my issues at this point..

If i didnt have a hard line id pinch it off over night and see if the fuel still left the bowl though siphon magic.

the Jb weld is curing and tomorrow evening ill most likely giver a go
 
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@max 02 wishing i had a pile of old dusty crusty pumps laying around.. death row is much further for me than it used to be haha!
 
@max 02 wishing i had a pile of old dusty crusty pumps laying around.. death row is much further for me than it used to be haha!

True! Lol!
I’ve always had lots of parts to swap around, but I’ve also been lucky enough to have had room to store them.

@79rustyk10 Andrew is working on his truck and he is going to use a pressure regulator just before the carb on his.
One of the reasons I brought up my story about the Monte.
Not say that is even your issue. I don’t know what else other than swapping carbs... And yeah... who do you know that lives close that has a good quad to try!? Google is awesome and very frustrating at the same time! I feel your pain Nick! I really do!
 
I'm installing the regulator because, looking back, most of the carb problems I had were related to high fuel pressure.

I've done a lot of reading, on many forums, and overly high pressure seems like too common of an issue for me to risk it again.

The Qjet likes pressure in the 5-5.5PSI or so area from my reading. Might be worth checking out.
 
True! Lol!
I’ve always had lots of parts to swap around, but I’ve also been lucky enough to have had room to store them.

@79rustyk10 Andrew is working on his truck and he is going to use a pressure regulator just before the carb on his.
One of the reasons I brought up my story about the Monte.
Not say that is even your issue. I don’t know what else other than swapping carbs... And yeah... who do you know that lives close that has a good quad to try!? Google is awesome and very frustrating at the same time! I feel your pain Nick! I really do!

Yea I appreciate it for sure, I didn't really think a mechanical fuel pump could make too much pressure but obviously if it's not the original one maybe someone didn't do their homework. I'll try n pull a number off it and check the Carter's info if I can. One buddy has a quick fuel 680 for sale , and there's a few 780 Holley's n what not if things get bad. But I'll probably shop around for another qjet. The motors never gonna go fast, and with how many times I pulled this one a part so far seems like the logical and cheapest route.

I'm installing the regulator because, looking back, most of the carb problems I had were related to high fuel pressure.

I've done a lot of reading, on many forums, and overly high pressure seems like too common of an issue for me to risk it again.

The Qjet likes pressure in the 5-5.5PSI or so area from my reading. Might be worth checking out.

Yea I'll see what I can find out with the vac gauge. Thanks for the info, that will help me troubleshoot some stuff!
 
If i disconect my fuel line and turn the motor over with the pressure/vac gauge hooked into the outlet , will that give me an accurate enough reading or will i get a dead head reading?
 

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