First carb rebuild....success

[Bonnewagon]

Re: First carb rebuild....fail

Adam, forget about the jets and all that. They only flow fuel on demand, based on vacuum from the engine. The overflowing fuel can only be from the fuel pump pressure, the needle/seat, and the float. The pump sends in fuel, the float opens the needle/seat so the bowl will fill, and then shuts it off at the pre-determined level. That's it. You are on the right track using an electric pump to fill the bowl and see what is up. Something is wrong, could even be a cracked casting, but I'm glad you are on a mission to find out what.

 

[CamaroAdam73]

Re: First carb rebuild....fail

My next day off is Thursday, and I'm going to experiment some more.

First, I'm going to remove the little retainer spring that clips the float needle to the float. Second I'm going to set the float lower than what it should be, thanks pontiacgp.

I can't pickup the micro pump until Friday (payday). Also i think I'm going to grab a small fuel pressure gauge and see what this pump is kicking out, haven't done that yet.


Lets re-cap

It's leaking fuel
Float is set correctly, and i tested the needle/seat myself Three times, same with the float. I also used my machinist ruler to set it, so i know it's dead on accurate.
So on Thursday, i'll A. check whats up with my fuel pressure, B reset the float LOWER than what it should be and remove the retainer spring, then see what happens.

Now if it continues to leak, and maintains normal fuel pressure than i'll have to pressurize fuel into the carb while i have it off of the car, with the airhorn off and carb on a jig so i can see exactly whats going on.


Speaking of fuel pressure, I'm uncertain of this because it's hard to remember but i THINK i remember removing the return line from the pump once, right after i had shut the engine down and as soon as i loosened the hose clamp fuel shot out with some force. It's a brand new tank/ sending unit lines and pump, so i doubt its clogged. But i guess stranger things have happened..

We'll know thursday night 😀

 

[Clone TIE Pilot]

Re: First carb rebuild....fail

Have you tried going over to Cliff's Qjet forum? I am sure he can give you some advise.

 

[Bonnewagon]

Re: First carb rebuild....fail

First rule of carb tuning is this: do only one thing at a time! That way you know what the affect was or wasn't. Also do not remove the spring clip from the float, it is there to pull the needle open when the float drops. Any decent vacuum gauge works as a fuel pump tester, there should be a PSI scale on it.

 

[CamaroAdam73]

Re: First carb rebuild....fail

Thanks for reminding me hah, i totally forgot my vac gauge has a PSI side.

Keep the retainer spring huh? Gotcha. You know whats weird though, even the book that i purchased from cliffs says to discard it :?: I'll keep it to be on the safe side.

As of right now the only thing i'm going to try is setting the float much lower than what it should be and see if it still floods the intake on a biblical scale.

 

[pontiacgp]

Re: First carb rebuild....fail

my good carb flooded out recently after using it for months...that retainer spring had fallen down the needle seat and prevented the needle from stopping the flow. I replace the needle and seat with the new spring but if I knew Cliff's book suggested to discard it I wouldn't have used it.

 

[Bonnewagon]

Re: First carb rebuild....fail

I'm sure Cliff has a good reason for discarding the clip, but then you are relying on fuel pressure to push the needle out of the seat, and if it sticks, no fuel. I'll check his book and see what the deal is. I do remember that Doug Roe, whose Q-jet book is my Bible, said to use it.

 

[kuruption109]

Re: First carb rebuild....fail

after reading this ill leave the carb rebuilding to the professionals LOL..

 

[pontiacgp]

Re: First carb rebuild....fail

please let us know Mark, I have it in there now and no plans to remove it but it would be good to know for future reference..

 

[CamaroAdam73]

Re: First carb rebuild....fail

Alright, so i fueled up the carb while it's off the car by running a long fuel line hose from the pump to the carb and setting the carb on my bench. i used a "trigger starter" to turn over the engine. The carb does not leak, and fires fuel as it should when i operate the throttle.



I've checked the timing, but im going to check it again. 19 BTDC is what it's at now

Here's exactly what happens, when it first fires up it runs good, but not smooth. it's a jerky idle, i keep it idling at about 1000-1100 RPM. maintains itself, and then i'd say 1 - 2 minutes later it just dies out. CHOKES OUT, it floods.

If i let it sit it'll fire back up, but die off again quickly, if i try to force it to stay running by giving it gas/ letting off it acts as an engine would thats getting too much fuel and choking out.


I guess it's back to the beginning. I'm off work tomorrow I'll check

Fuel pressure
Timing when its running right, and what the timing does as the engine starts to die.
Compression one more time just for sh*ts and ****ing giggles
Check the plugs to see how its burning

There's a chance this could be ignition related, maybe a cylinder isn't firing and its flooding? The distributor is the original one that was there when i bought the car. The shaft of the dist is made of aluminum and it's oxidized as hell. I haven't bothered to pop the cap off yet The coil contacts look good though, and it's an AC delco dist.