[Bobalong]

Well if I keep after it I'll figure it out.

It just wasn't that hot today, (80's then dropped to 70's) I replaced the intake carb gasket with this multi layered 3 metal, 4 gasket sandwich, warmed the car up, went for a spin, brought it back. Washed it, blew it dry. Went to start it, it fired for one second, died then I had to crank it for maybe 10-15 seconds, then it started. Ran fine. On hotter days, I've had to crank till I started wondering how much longer the battery would keep up.

When I looked at the bottom of the carb during gasket replacement I could see fuel in the intake, under the primaries, where I had rolled the accelerator linkage to make the fuel squirt. (Accelerator pump good).

I looked at the two plugs I installed last year in the bottom of the carb and there was no fuel dripping from them. They were dry.

Some have suggested that the fuel pump or fuel line is vaporizing the fuel after shut down. It just wasn't that hot. today. The fuel pump isn't that old, and the fuel line is a factory steel repop. So I'm a whole lot of factory, and these didn't have hot start issues when they were new. I use 93 ethanol and 89 non ethanol depending on what's available.

I'm still using the same tank of non ethanol I bough a few weeks ago. Although, there was still 5 or so gallons of ethanol gas in it when I topped it off with the non e. Hard to believe that would make a difference.

One odd thing I have noticed is if I am going say 40 MPH, and brake suddenly as if I'm turning in a driveway, the engine will bog down as though it wants to die, then it will recover. Happened tonight. I braked, turned in the driveway, went to neutral and the engine was ready to die, I put it in reverse, backed out and I thought it was gonna die, put it in drive and as I gassed it just a little it recovered.and off I went.



WTH is that about ? Are these things related ?

Carb built with Cliff Parts.
068 Cam
RAIII exhaust manifolds
Total rebuild on engine less than 500 miles ago. Runs like a scared rabbit when I light em up.

Maybe as someone suggested I need to keep some AV gas around, or add some xylene and a little 2 cycle oil for additional lube
get the octane up closer to what the ole Sunoco stations used to sell.

[tom s]

Just sounds like it's flooded to me.Tom

[Formulas]

When your cranking for 10 - 15 seconds are you pumping the excelerator or just cranking or what?

Also often times carbs take the blame for ignition capers

.

[Blackcat]

Sounds like your float in your carb is heavy. Is it the penenolic one? If so they tend to last about 3 years and then they start to soak up gas and the carb tends to flood easier. going to a good brass one solves the issue. I had flooding bogging issues with my truck a couple of years back and found out I had one of the plastic floats in the carb. I was certain I had gotten rid of them all...

[Cliff R]

The later style closed cell nitrophy floats are fine in any of this new fuel. The new production brass ones are more likely to sink to the bottom of the bowl. Every single one we put in service failed, probably this new fuel eating the solder out of the seams. We've never had any of the new style Q-jet float have any issues. The one in my own carb is nearly 20 years old and we've never had to replace any that we've sold since going full time in this business back in 2003.

The symptoms do indicate a flooding condition, not heat soak or boiling fuel in the carb.

Couple of things to check that will cause this that get missed during rebuilds.

Check the gasket under the N/S assembly. A tiny leak there from an imperfection in the casting or a piece of the old gasket material left in place with cause very similar issues as you are having. A very slow leak there may not show up when running as gas typically leaves the bowl quicker than the leak so the fuel level doesn't get too high. When shut down if there is still pressure in the fuel line the bowl will continue to fill some and make for difficult hot restarts.

Leaking at any of the bottom plugs will cause the same issue, especially the front plugs as they are a direct path into the intake. Pressure test the casting as you may not be able to detect a small leak just letting the casting sit on the work bench with fuel in it.

Make sure the clip on the float isn't hooked thru either hole in the float arm, this can/will cause intermittent flooding issues. The open part of the clip faces forward, or you can leave it off all together as this will also prevent any drainback from the bowl after shut down.

Some will tell you that the needle can stick or get "glued" into the seat, but I haven't seen this happen and I haven't had a clip on the float in my any carb I've used dating clear back to the mid-1980's.......Cliff

[Bobalong]

Originally Posted by Formulas

When your cranking for 10 - 15 seconds are you pumping the excelerator or just cranking or what?

Also often times carbs take the blame for ignition capers

.

I've tried it both ways.
Pumping doesn't help.
Not pumping doesn't help.
Holding it to the floor doesn't help.


And you're right . Ignition is next step.
I'm HEI, new plug wires, dist cap, distributor, plugs
Hei modules are pretty much on or off. Either they work or they don't.

[Bobalong]

Well after all the speculating and chasing potential gremlins, thermal gasket, non ethanol gas, rethinking my rebuild on the quadrajet considering fuel pump replacement, checking fuel pump flow . . . . . .

Well . . . .I used two hose clamps as a precaution when I replaced my fuel pump tank supply tube at the pump a few years ago. Both were loose, not enough to ever drip, but loose enough to suck air. And then I tightened them.

My engine now starts like a champ, hot or cold. Such a simple fix.

It's always the last thing you fix, isn't it ?

[unruhjonny]

huh...

I saw your other thread, and stopped popping in it after it seemed that evidence was pointing to the fuel pump;

Originally Posted by mgarblik

Your problem is a tough one to deal with because multiple factors can be involved. Based on your description of the problem, the carburetor base gasket will not solve it. The number 1 factor is the fuel itself. Modern fuel is not designed for engines with carburetors. That alone is an issue. The vapor pressure is so high, vapor lock is always an issue on hot days. Probably the simplest fix that would really help is a new mechanical fuel pump with a return line to the gas tank. Many AC equipped cars from the 60's came with one. Another fix that is more of an aggravation, especially if on a long trip is adding just a little race gas to a full tank of pump gas. Just 1 gallon to a full tank will make a world of difference as far as vapor lock. Another fix is a low pressure electric pump in the supply line between the tank and mechanical fuel pump. Having low pressure, just 2-3 lbs vs vacuum in the line naturally raises the boiling point of the fuel. Good luck with the fix.

I just did a quick review, there were people posting that no carb gasket of any kind would make a difference...

[Schurkey]

Originally Posted by unruhjonny

I saw your other thread, and stopped popping in it after it seemed that evidence was pointing to the fuel pump;



I just did a quick review, there were people posting that no carb gasket of any kind would make a difference...

http://forums.maxperformanceinc.com/...d.php?t=820191
Posts #2 and #4 nailed the problem in the previous thread. But he wasn't listening.

[694.1]

Interesting resolution. I find that the only real car issues I have are because of my failure to understand what is happening.
Once we figure it out...That is the hard part!