3.0 w/ Webers wouldn'd start

[ckissick]

My 911E has been very good to me for a long time. Until today. After driving it around town for a about an hour, I parked it for 15 minutes. Then it wouldn't start. It was not a hot day, about 70 degrees.

(Great, I thought. Yesterday the Tristar's starter went out and I limped into a shop, where it still sits. This morning, the Westy wouldn't start, so I had it towed into the same shop. Three's the charm?)

Anyway, since I had no other cars available, and am getting too familar with the tow truck driver, I decided I would crank that baby with the gas pedal all the way down until the battery went dead. The battery is good, so I cranked it off and on for about 10 minutes, then it finally fired right up and ran great. No smoke, either.

So what could it be? What can I check on the Webers? They are newly rebuilt and in good shape. Or could it be electrical? Ideas? Please, I'm down to my last car. (The '50 is not at home.)

[gumba]

Sounds like electrical, not the Webers.

[RoninLB]

you may have flooded it ?

[Mo_Gearhead]

Well, if it only happened once, I agree that it somehow just got flooded.
If it continues to happen, I would suggest the float levels may be too high.

Although only 70 degrees (ambient), the engine gets HOT after driving and then when parked, the carbs can 'heat sink' (absorb additional heat) and cause the fuel (if setting is too high) to percolate and flow gas into the manifold (flood).

[ckissick]

I'm thinking they got flooded, too. But do both carbs flood at the same time? And if not, won't the car start but run rough with one flooded carb?

Although I rebuilt the carbs and set the float levels less than 2000 miles ago, I could not remove the old needle valves. They just would not loosen. So I have old needle valves. Could this cause it?

[Mo_Gearhead]

QUOTE: "So I have old needle valves. Could this cause it?"
________________
Yes. If the tip of the needle is old/worn it will not seal correctly. That allows too much gas to enter the float chamber. I can't imagine why they would not come out? Perhaps you just didn't feel comfortable 'forcing' them? I bet they are your problem.

[Mo_Gearhead]

QUOTE: "...won't the car start but run rough with one flooded carb?"
_________________

'Carb. flooded' is actually a misnomer. The carburetor(s) overflow, causing excess fuel to be introduced into the manifolds and then into the cylinders.
We are actually discussing 'cylinder/engine flooding' ...caused by the carb(s) problem.

Webers like LOW fuel pressure. The needle/seat is all that is holding back the fuel flow. A dirty/worn needle seal may be your problem.

[ckissick]

Thanks, Mo. I bet that's it. I tried very hard to loosen all four needle valves, but they wouldn't budge. When the socket started to strip the brass nut on one of them, I gave up. I think I'll remove the carbs and take them somewhere like a machine shop to loosen the nuts.

[Mo_Gearhead]

Be certain you check your float levels again, carefully, on re-assembly. Too high a setting can also create the problem of flooding.

[Steve@Rennsport]

All good advice,....

Based on my personal directive about never "ass-uming" anything from a "No start" complaint, the very first thing I do is confirm the ignition system. This prevents me from chasing off in the wrong direction as well as establishing a firm foundation to troubleshoot the fuel system.

Once I see a nice healthy fat blue spark while cranking, only then do I examine the fuel system components and setup.

Do you have insulator plates between the heads and the intake manifolds?

[ckissick]

Originally Posted by Steve@Rennsport

All good advice,....
Do you have insulator plates between the heads and the intake manifolds?

Yes, I have insulator plates. I would have liked to have looked at the plugs, but my only helper was my 6-year old girl. And she cried when it wouldn't start.