I just rebuilt my 75 qjet and got in on the car tonight. Things went well until now. Heres a little info about my rebuild before I start with the problems:
Cliff's high performance rebuild kit. They customized everything for my engine (yearone 350 425 hp). I assume all the parts( jets, rods, etc.) are correct and all work together. Lars says its a no no to use brass/aftermarket idle screws...should I switch back?

I get it all together, have some starting issues but backed out the idle screws some and it was running pretty good. Went for a test drive and I noticed a little bit of hesitation/bog around 40 mph. I think this means Im a little lean? I have the solid block apt in the corner not the middle like later years. I have it at two turns out like Lars suggests in his papers(any suggestions wth this also?). I figured that was ok. But then on my street I did a small WOT blast and when I let off it bogged then died. I could smell strong gas and so I took off the air cleaner and some smoke and strong fumes were coming out. There was also gas around where the accelerator pump rod comes out and maybe some near the primary throttle shaft on the drivers side(could be from acc pump leaking down?, it didnt have this problem before the rebuild)
I searched on here and saw low float causes surging and high float causes fuel to come out the acc. pump rod hole. Possibly one of these? I could not restart the car, seemed to be flooded. I got it to start by flooring it and was able to get enough speed to roll me on into the driveway, but it would harldy run.

I havent set up the choke yet, but I didnt think it was the problem because wired it open with the seconday pull off linkage.

Can someone lend some help here? I was excited about actually getting it to even run since this was my first time, but it seems like im not done yet.

Thanks,
Sean

 

It sounds like it's flooding, either the float is too high or something stuck in the needle/seat vavle.

 

any more suggestions before I tear it apart?

Sean

 

You can temporarily/permanently disable the choke by turning the black bakelite disk (bimetallic spring under it) to hold the choke full open. This won't interfere with other operations. Don't tiewire it.

Check your fuel pressure. A qjet will frun fine with as little as 3 psi. Flow is what you want, not pressure. Best to use a regulated return to set pressure. A lot of people run far more than necessary.

Recheck your needle and seat for level and dirt.

Test for secondary coming in to quickly for bog.

 

Just opened it up. I did find a little piece of metal on the rubber seal of the needle...hopefully that was the probem. On measuring float height do I measure from the front ( farthest from needle) or the closest side. I know I should be around .4 for my setup but maybe I measured wrong.

I'm using a new, but stock 75 fuel pump. I didnt have problems before so I think I can knock that off the list.

Thanks for the quick responses. One last questions: should I swap back to my stock idle mixture screws or use the ones supplied? At the right setting the both accomplish the exact same flow right? So their shouldnt be a difference?

Thanks,
Sean

 

be sure to put some finger pressure on the float hinge pin while setting float level............

 

Yeah I put pressure on the needle while holding the pin down also. But where do I measure? I measure at the nearest side of the float to the needle and put it at 13/32 or .406". Was I supposed to do the toe end? Either way that puts me at the right height or too low.


Thanks,
Sean

 

I have another quick question:
I noticed my new acc pump is alittle different than the one that was in it. The one I took out was from a rebuild kit done by a guy a couple years ago. The shaft is a little longer on the new one, could this squirt fuel out all the time, or does it not do anything as long as its not moving down? And the other difference is the seal spring. The orange (new) one is tighter with less give on the seal, the other is softer and more flexible. Is there a difference or a better one?


Thanks,
Sean

 

Alright, its looking good now. It was either that little debris on the needle or the float. I was looking at the float, im pretty sure I measured wrong but its good now. The problem was that while I held the hinge pin down and measured it was fine. But the hing pin was a little bent and I didnt think it mattered as long as it was at the right height. But when I put the black float retainer cover on I noticed it didnt hold the hinge pin securely down in the groove. The float would rise and lift the hinge pin just barely, but it went another 1/4" up. So I think that was the problem, I bent it back and everything is great.

I can finally roast the tires by flooring it from a stop

Thanks for all the help and support with these problems. I would rather do something wrong a few times and learn about my car rather than pay some mechanic to do it for me (and most likely wrong).

Thanks,
Sean