hot weather and UNHAPPY 48IDAs (I am getting tired of this)

[Jim Ratto]

Well, warm weather is back for now, 85F+
And my 48's are doing the same thing again after warm up and shut off and restart

runs fine when "warming up" after first start up in morning
drive it and get engine to temp (170-180F oil)
shut car off, walk away for 10 min
get back in car restart, and idle is all wrong, pop pop pop, flat spots, limping idle, hesitation...

60 idle jet in 120 holder, 2.00 needle valve, floats as per Weber instructions, 7/8 turn out mixture screw
3.0 psi, Red Holley pump and regulator, fuel line is AWAY from headers

I'm ready to roll car off a cliff.

[Rick Meredith]

Does the problem ever go away?

ANd if you roll the car off a cliff... let me know where and when and I'll be there with my catcher's mitt 

[Jim Ratto]

Does the problem ever go away?

ANd if you roll the car off a cliff... let me know where and when and I'll be there with my catcher's mitt 

only when engine cools off.

I looked down throats, I don't see fuel bubbling over when it does this, like you would think.

I don't know what to do.

[Rick Meredith]

Have you thought of insulating the fuel line under the car?

The Pump is by the tank? What about the Regulator??

[Jim Ratto]

pump is opposite brake master cylinder
AN-6 line through tunnel, then routes to RH side, up above trans, near where Z bar goes through body, then into engine comp through body (Rh in front of RH 48IDA)
regulator is on firewall in front of fan shroud, near decklid spring.

I don't think line is getting hot, but I will try isolating that possibility with a cold rag or something next time it does this and I am ready to go at it with a sledgehammer.

[Rick Meredith]

ok and since the reg is on the motor end the line should be pressured enough to stop vapor lock.

[Rick Meredith]

It sounds like some sore of heat soak problem.

[Jim Ratto]

most frustating bit of this.... it hasn't ALWAYS done it.
started off and on a few years back

I wonder if it has to do with the "new" gas?

Only other thing I can think of is this: when I blew my ring gear out at Sac one of the guys that "helped" me pull my car apart decided to blow compressed air down the jet cavities. Dumb move, as that squashed one of my floats. A year later when i got car going again, I found the squashed float in the carb, and replaced it with new one. Now that I sit here and rack my brain, I think the new float had another tab on it (besides the one that contacts needle valve). If the float has this extra tab (near float bowl wall) and I never "adjusted it" could it somehow be causing this? Does gasoline expand when it gets hot?

I am willing to try anything at this point.....   how's that CB injection?

[Rick Meredith]

hmmm I think I'd check the float out. Usually the second tab would be to limit downward travel.

[Jim Ratto]

hmmm I think I'd check the float out. Usually the second tab would be to limit downward travel.

right.... it would hit either the needle valve (down travel)  OR the wall of float bowl (Up)
depending on where tab is bent

[Jim Ratto]

what would make fuel level "drop" after the car sits there hot? Or what would make fuel supply dwindle after car sits warmed up?

[Shubee2 (DSK)]

what would make fuel level "drop" after the car sits there hot? Or what would make fuel supply dwindle after car sits warmed up?

Sounds Like its Time for a Set of 42 DCNF's  they always run good

[Rick Meredith]

Can you see that the level is down in the float bowls?

[Jim Ratto]

Can you see that the level is down in the float bowls?

Naw, I guess I could look down the vent hole after the car sits hot and see WTF is going on.

I am ready to hire somebody to come exorcise this gremlin from my life.

[Rick Meredith]

May I recommend "The Blessing of the Cars" Car Show? 

Held the last weekend in July at Hansen Dam.

Get you car blessed by a Catholic Priest, 

[John Rayburn]

Jim, I'm inclined to agree with Rick about a heat sink issue. Have you checked how hot the manifolds are after the car is shut down for a little while? I've noticed problems like this also when they change from winter to summer gas or the opposite, and the weather changes back to hot with winter gas, or cold with summer gas, if you get what I mean. Also, the alcohol in the gas turns into this shitty white residue that can leave a needle valve open enough to seep. Food for thought....

[Jim Ratto]

Jim, I'm inclined to agree with Rick about a heat sink issue. Have you checked how hot the manifolds are after the car is shut down for a little while? I've noticed problems like this also when they change from winter to summer gas or the opposite, and the weather changes back to hot with winter gas, or cold with summer gas, if you get what I mean. Also, the alcohol in the gas turns into this shitty white residue that can leave a needle valve open enough to seep. Food for thought....

thanks guys, back to the fricking garage instead of the driver's seat. 

[John Rayburn]

May I recommend "The Blessing of the Cars" Car Show? 

Held the last weekend in July at Hansen Dam.

Get you car blessed by a Catholic Priest, 

                                                   The new monorail at Disneyland is a big piece of shit. The other day they had 19 nuns visiting from Rome. They asked the Nuns to bless the new Monorail and they were promptly able to drive the thing around the park without a hitch. They are now going to be able to put it into full service sooner than expected.

[Jim Ratto]

John, I'd like to pick your brain.... I'll try to call you this wekend. 

[John Rayburn]

Give me a holler!!

[louisb]

When was the last time you drained your tank? Does it matter if the tank is full or half full or empty? Did this start after you parked your car while you took a break from VWs a few years ago?

Just a thought.

--louis

[stealth67vw]

what would make fuel level "drop" after the car sits there hot? Or what would make fuel supply dwindle after car sits warmed up?

Sounds Like its Time for a Set of 42 DCNF's  they always run good

Except in high speed, long sweeping turns.

[John Rayburn]

what would make fuel level "drop" after the car sits there hot? Or what would make fuel supply dwindle after car sits warmed up?

Sounds Like its Time for a Set of 42 DCNF's  they always run good

Except in high speed, long sweeping turns.

                                                Or if you use a 42 or bigger venturi....

[Bruce]

Can you see that the level is down in the float bowls?

Naw, I guess I could look down the vent hole after the car sits hot and see WTF is going on. 

Jim, get yourself a piece of 1/8" Al welding rod, about 3" long.  Insert it down the vent hole until it contacts the top of the float, but does not push it down.  Make a mark where it is.  Compare to the other side.  Repeat when hot.

Gas expands by a huge amount when heated.  It's rate is 4 times that of water, and 13 times more than aluminum!

[Sam K]

I know it might be a longshot, but my old mustang used to act like that on hot days and turned out that the fuel tank vent was plugged. I used to have to pop the gascap off to let out the pressure and it would start. It might be worht a shot.

[Harry/FDK]

Just a thought: I had about the same problem with IDF's as soon as i switched to the aluminum case....Heat. After i mounted some phenolic spacers between the manifolds and the carbs, the problem was gone.

With my short manifolds for the IDA's i'm thinking of stacking 2 spacers per carb on this thing.

[Frank LUX]

Hey Jim,

Where on the Motor is your Fuel Regulator installed...

Frank

[Jim Ratto]

Can you see that the level is down in the float bowls?

Naw, I guess I could look down the vent hole after the car sits hot and see WTF is going on. 

Jim, get yourself a piece of 1/8" Al welding rod, about 3" long.  Insert it down the vent hole until it contacts the top of the float, but does not push it down.  Make a mark where it is.  Compare to the other side.  Repeat when hot.

Gas expands by a huge amount when heated.  It's rate is 4 times that of water, and 13 times more than aluminum!

COOL, thanks Bruce, I will try to get a look see this weekend.  Maybe I can at least see if level is going up or down and then the fun part..... finding out the culprit. Like I've said, this hasn't always happened.

Theories:

2nd float tab limiting travel one way or the other (I don't know which without going inside carb and looking)

Holley pump and regulator causing problems (yes I have had problems in the past) or lines between regulator and carbs getting heat sokaed? Sometimes when engine is off, after warm up, I can hear "something" going on inside of Webers, but as I mentioned I do not see dribble on top of throttle plates. And if it was flooding, wouldn't the thing run pig rich when fired? it doesn't it does the exact opposite. It acts as if the mixture screws are closed or near closed. In fact, if I go back and reset mixtures as this is happening, I can richen it up, but then it runs like crap too....just doesn't pop.

fuel formula? then why isn't everyone else having this trouble in CA?


where do I buy phenolic spacers for 48IDAs I can't find them anywhere.

[Jim Ratto]

Hey Jim,

Where on the Motor is your Fuel Regulator installed...

Frank

Hi Frank, thanks..... it is on firewall in front of fan housing, centered between carbs.

[Rick Meredith]

where do I buy phenolic spacers for 48IDAs I can't find them anywhere.

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