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yh carb rebuild gas leaking from throat of carb when idle
Posted by: Kappa1953$ ()
Date: January 21, 2023 06:34PM

Purchased 64 monza spyder that was running so rich that all spark plugs were black and flume burn your eye. I rebuilt the carb it starts and runs pretty good but, gas comes out of the throat of carb. Does anyone have a answer to my problem?

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: steve c goodman ()
Date: January 21, 2023 06:51PM

Make certain seat is tight in carb top
Make certain float will float
Make certain float level is correct
Make certain fuel pump pressure is no higher than 2 1/2 psi
Make certain pump diaphragm cover is smooth
Make certain pump diaphragm is not torn/damaged
Make certain choke setting is not too tight

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Kappa1953$ ()
Date: January 21, 2023 08:32PM

where is the best place to install fuel pressure regulator on a 1964 monza spyder and what is the best regulator to use?

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: vairmech ()
Date: January 22, 2023 05:49AM

The biggest thing is fuel pressure. It probably is not your settings.

I thake the top off the fuel pump and cut and rebend the spring for a lesser pressure.

If you do actually use a pressure regulator DO NOT go cheap! The ones with the dial on them are not pressure regulators but rather just variable restrictors.

My suggestion for regulators is something like this, it is 4.5-9 psi adjustable and might even go lower, Trick Flow Pressure Regulator

Then if you really want way better quality I have used these in the past with NO issues, this one is also a lower pressure from 1-3 psi, Fuel Lab Pressure Regulator

While the link is from Summit Racing it was just an easy way to get the info.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: steve c goodman ()
Date: January 22, 2023 08:21AM

Ken is correct DO NOT GO CHEAP with a regulator.

You should check fuel pump pressure at the carb inlet first so you know what you are needing to fix.

You don't indicate whether mechanical or electric pump but no matter, the regulator generally chosen is Holley 12-804. It will adjust down to the low psi and hold the setting. The only dislike in my opinion is the size. It is just a bit bulky to get mounted.

I am always concerned with flex/rubber fuel line in the engine bay so mounting the regulator on the engine and plumbing steel line in and out is time consuming and difficult to find a place where it looks nice or is hidden from view.

Many mount the regulator on the bulkhead near the air cleaner or even on the frame rail but that does require rubber hose connections because of engine/powertrain movement.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Timothy Shortle ()
Date: January 22, 2023 09:24AM

I might also suggest Bob Helts (R I P) book on the Carter YH carburetor. Buying a fuel pressure regulator without
knowing what your fuel pressure is is nothing more than guessing. Might as well buy a lottery ticket as well.

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: PequotMonza64 ()
Date: January 25, 2023 11:34AM

And most of what I hear about engine fires in Corvairs has to do with putting rubber fuel lines in the engine bay.

If you don't need a fuel regulator, why add one?

Check the pressure.

You're not just describing a problem with the float needle and seat are you?

The first rebuild I did with everything stock just blew right past and poured into the carb because it was not installed correctly.

Glen in Ohio
1964 Monza Sedan Powerglide 110 hp
Low mileage survivor, stock as delivered
Records back to 1967 in Pequot Lakes, Minnesota
Original dealer Mike Turk's in East Liverpool, Ohio
Located in Cleveland, Ohio area


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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Frank DuVal ()
Date: January 25, 2023 08:16PM

Listen to Steve and Ken's suggestions. YH carbs are sensitive to fuel pressure. Buy enough fittings to tee in a pressure gauge.

Frank DuVal

Fredericksburg, VA

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: JimBrandberg ()
Date: January 26, 2023 04:16AM

All good stuff so far but I'll add a few thoughts.

I don't understand if "when idle" means the engine is shut off and "idle" or if it means the engine is running at slow speed "idling".

The small return to gas tank that comes off the stock filter might diminish fuel pressure a little when the engine is running but it also gives residual pressure somewhere to go when you shut the engine off.

The excessive richness you experienced before rebuilding your carburetor may very well have come from a tear in the accelerator pump diaphragm.

Sometimes excessive raw gas situation can be improved by changing the float level measurement from 5/8 to 3/4".

The Carter YH doesn't like much fuel pressure as folks have already said.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: vairmech ()
Date: January 26, 2023 04:35AM

Frank DuVal Wrote:
-------------------------------------------------------
> Listen to Steve and Ken's suggestions. YH carbs are sensitive to fuel pressure. Buy enough fittings to tee in a pressure gauge.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

LOL, I think both of the regulators I posted are capable of mounting a gauge! I use liquid filled gauges back in the engine compartment.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Timothy Shortle ()
Date: January 26, 2023 05:51AM

I think the poster has left this conversation.

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Turbo coupe ()
Date: January 26, 2023 07:46AM

I had that problem and found that the original needle used a little spring to stop engine vibration from causing the needle to bounce off the seat you might check into that I think that we found that there was a minor difference in the kit for
a Corvair from the one made for marine carbs a AMC ones

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Frank DuVal ()
Date: January 26, 2023 10:07AM

I mean to tee in a gauge to see what is happening before buying the regulator. Yes, the regulators have a port to screw in a gauge.winking smiley

Frank DuVal

Fredericksburg, VA

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: flat_six ()
Date: January 26, 2023 03:10PM

I've used the all metal inlet valves (two steel balls). Seems to work well to hold back the fuel when needed.

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: joelsplace ()
Date: January 26, 2023 07:57PM

Check that the tang on the float meets the needle perpendicularly.
If it doesn't the float will be less able to resist fuel pressure. I believe it is why a lot of the kits come with different thickness washers for under the seat or multiple washers.

Joel
Northlake, TX
5 Ultravans, 141 Corvairs and counting...

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: jjohnsonjo ()
Date: January 27, 2023 06:14AM

2nd, 90 degrees on float tang angle

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Murphy ()
Date: January 27, 2023 05:54PM

I recently had that problem, float wasn't set properly.

65 Monza Coupe
61 500 Coupe-W100181
Earliest '61 Alive?

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Re: yh carb rebuild gas leaking from throat of carb when idle
Posted by: Winsamfarm ()
Date: January 28, 2023 05:28PM

My primary was spitting fuel from the small vent holes on the side that the exhaust valve seat dropped out of. Will find out if that stops when I get the head back in.

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