1BOSS83

I'm having an issue with starting the H/O.

With the car at full operating temperature; shut it down, count to 10, hit the key and it roars right back to life, no issue.

let it sit for 10 minutes:
hit the key and fires right up

let is sit for 20-25 minutes: 5-6 seconds of cranking and will come to life, idle at 900->800->700->600-> shuts down (like its running out of gas). Hit the key again, no. Tap the gas, no. Fully engage the choke and when it DOES fire I get a big cloud of unspent fuel as It's clearly been flooded. Once more when it does fire you have to stay in the gas to keep it from stalling.


Yesterday after the bout of getting it started I was leaving a parking lot and had to accelerate quickly as I was entering a high MPH road. When I got in the peddle it stalled and (not for any flare of dramatics) I came within a few inches of a serious accident, so I'm considering this an urgent issue that I need to correct before I take it out again.

I started noticing this problem after I switched to full manifold vacuum for the VA canister vs. the ported. I switched to full manifold vacuum after a lot of research that suggests that during times of greater vacuum the earlier the burn is started the better. Idle being the case and point.

Obviously, I can switch it back to ported but I want to rule out choke etc before I dig into the VA situation.

Thanks for reading and comments.
Pictures, videos, or any other reference material is not a problem.



Reference:
Timing is set to 31* total
slayer 750 carb 80/82 jetting, choke is on the leaner side, 1000 rpm idle (15"HG)
Plugs- AC Delco 43s, .040 gap, reading grayish tan, porcelain white, no smell of gas.

These issues have happened in temperatures ranging from 60*-75*

coppercutlass

Needle and seat. I just went through this. Take the bowls out and just clean them. Make sure there us no debris in the needle and seat. It keeps dumping fuel after its shut down. Look down the throats of the carb and see of there is sepage after its shut down.

captjim

I don't think so, the needle/seat allows fuel into the bowl, but has nothing to do with the fuel getting from the bowl to the engine. It could be the carb leaking down, for sure, but the needle/seat will not cause that.

1BOSS83

If the carb was leaking down why would I have to get into the peddle so much to get it to turn over?

Fun71

Could be lots of fuel in the intake and not enough air, so pressing the pedal causes the throttle plates to open and let more air in. That's the typical procedure for getting a flooded engine to start.

1BOSS83

Heard that. I'll get it cleaned up and report back tomorrow

coppercutlass

Capt Jim I disagree. Lots of experience here with stuck needle and seats. The residual fuel psi will push fuel out.

captjim

Don't see how. With the engine not running, no fuel pressure on an engine with a mechanical pump. Been working on cars my whole life, 20 years professionally, never heard the term "residual fuel pressure". If the needle/seat are leaking, the car will flood and run rich at idles, as the pump will deliver more than the engine is using. We have all seen that as well as stuck or saturated floats. None will cause the problem the OP is describing, IMO.

coppercutlass

You ever look at a fuel psi gauge after shutting it down. It does not go to zero. That's residual.if it's stuck the fuel psi will bleed off if the needle and seat are stuck. I'm not kidding when I'm saying I just fixed this issue recently.

1BOSS83

Cleaned needle/seat. 5 minute drive to gas station, filled up, hit key, fired right up, drove another 20 minutes, came home, shut down, 45 minutes (timed) rest period.

https://www.youtube.com/watch?v=A8Zl...ature=youtu.be

35 minute test coming next, richer choke.

1BOSS83

Adjusted the choke, but, the first time to drive it was yesterday and it's 25* colder than the original experiment. I'll keep posting any changes to the tune and their related effects. Same hoopla after a sit.

1BOSS83

I thought I had this worked out but I do not. I watched the holly videos and set the choke exactly as directed.

I just went to get a hair cut. Car was at FULL operating temperature. Shut down at 2:53, back in car at 3:23. Hit the key, lots of cranking. Tried to give it gas- it would roar over and die if I gave it too much. Tried to give it a little and it would whimper to life and slowly die out. I'm at my wits end here. I think something is wrong with the choke circuit but I don't know how to troubleshoot a hot start choke issue. I cannot for a moment believe that a car at full operating temperature would require gas to start after sitting for 30 minutes on a 75* sunny day.

While I had the hood open- I engaged the throttle linkage and let it snap back naturally- What I got (oddly enough) was two good streams of gas and then a few extra trickles.

I'm pulling the bowl off tomorrow for a better look. Maybe the **** gas is eating the O-ring.

Thank you

droldsmorland

Mine would do this. I traced it to fuel boiling in the carb (today's shet gas). I put an insulator/isolator gasket under the carb, blocked off the heat riser crossover(welded the iron plugs into the intake not the heads) then wrapped the head pipe by the starter with a high end blanket from Jegs.. Hot start problem completely solved. Its a tad cold blooded when the ambients cold but I dont drive it unless its warm. This could be easily remedied by converting the carb to an electric choke and eliminating the divorced style.
Verify the fuel filters in good shape.

FYI DO NOT run ethanol gas in any carbureted engine.

coppercutlass

Next time you are out messing with the carb. Check and make sure your rear secondaries are cracked open. I had issues before too with loading up and what not because the idle circuit was not properly working as I was relying on just the front throttle plates for fast idle settings. The rears need to be open a hair in order for the idle portion of the carb function to work right. Just a thought.

Personally I have not encountered fuel boiling with the ethanol 93 and I do some pretty hard driving. My underhood temps get ridiculous hot too during the drive home after a day at the track. But that's just my experience.

1BOSS83

I took off the primary bowl, reset the float, carb clean soaked the needle/seat (o-ring wasn't chewed up as I had heard/read it could be). Cleaned up the choke plate/exterior mechanisms.

Started it yesterday, choke operated normally, went to church, 1 hour of sitting in the lot, got in, hit the key and fired right up no problems. Drove it around all day, no issue at all. Hopefully all is well now.