I was working today on some electrical stuff in the engine compartment, so I had the ignition on for an extended period (minutes), which kept the electric fuel pump running, without the engine running, for a while. At one point, I heard a distinct change in the sound of the fuel pump and later I began to see gas leaking out of one of the secondary carbs.

I eventually got the car running before I discovered the problem.

When I looked down the throat of the carb, I found a deep puddle of gas.

At this point, I'm wondering if damage has been done to the inlet needle valve or if I need to re-adjust the float assembly, which perhaps got distorted.

It's hard to understand why the needle valve would fail when it is constantly holding off against the fuel pump pressure during most of the low-throttle driving I do.

The car had been sitting around for several months without use before I started it today.

1966 140 Monza PG convertible
Ventura County, CA

I might rap on the carburetor with a small hammer and keep an eye on it to begin.
I worry about hydraulic lock and often remove the spark plugs to turn it over and be safe, hate to bend a rod or something and fuel wash on the cylinder walls and into the oil isn't so good either.

Jim Brandberg
Isanti, MN
CorvairRepair.com

Interesting read. I am starting to thing that my 140 fuel problem (another thread) is possibly my pump putting out too much pressure - leaking past the needle seats as it sits after I kill it. I have a pressure gage on the way to test.

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]

vairTer Wrote:
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> I was working today on some electrical stuff in the engine compartment, so I had the ignition on for an extended period (minutes), which kept the electric fuel pump running...

A common problem that surfaces when people switch to an electric pump. Probably too much pressure but also could be a needle valve tip that seated a little off-center , a float level issue or a float filled partially with fuel.

That's why I like mechanical pumps if you can find a good one. Mechanical pumps only pump when the engine runs, they pump a little at idle and a lot at high RPM just like the engine needs. E-pumps deliver the same amount of fuel volume and pressure pretty much all the time which is over kill at idle.

I have also seen some needle seat inlet hole diameters that are larger than they should be and this means the floats have to push even harder to seal against high fuel pressure when the bowl is filled.

Dave W. / Gilbert Arizona
65 Corsa 140/4 Butternut Yellow
66 Corsa 140/4 Stinger Tribute
66 Corsa 140/4 w/factory A/C Aztec Bronze
65 Monza 4DR 140/PG w/factory A/C Ermine White
65 Monza 4DR EJ20T/5 Light Metallic Blue

I've seen mechanical fuel pumps with 9#s of pressure. it's electric for me unless someone comes up with a good mechanical. I've got 2 milk crates full of in case rebuilding them comes in fashion.
I get needle and seats that are I believe .086 like original LMs. Some you get are over .100. I started paying attention to them when trying to stop the drippy cluster syndrome.

Jim Brandberg
Isanti, MN
CorvairRepair.com

Remember,........... azdave makes a nice pressure adjusting kit for the stock mechanical fuel pump.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

High pressure is one problem.
An internal leak is a bad thing. It doesn't lubricate well and finds its way outside.
External leaks are a fire hazard.
I put up the good fight for a long time but grew weary.

Jim Brandberg
Isanti, MN
CorvairRepair.com

American Mel Wrote:
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> Remember,........... azdave makes a nice pressure adjusting kit for the stock mechanical fuel pump.


There a thread here detailing it? I hav a pressure gage showing up today, but would invest in a system that would allow me to accommodate fuel pump changes in the future without worrying how off the new one is . . .

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]

As stated. Check the fuel pressure of the electric pump.
I run electric pumps that are low pressure, 2.5 - 4 psi.
I would also check the float valve as stated, and the float
compensater spring. This should be adjusted so the float is
near weightless according to the factory Delco Line 9 manual.

Corventure Dave

gerg Wrote:
-------------------------------------------------------
> American Mel Wrote:
> -------------------------------------------------------
> > Remember,........... azdave makes a nice pressure adjusting kit for the stock mechanical fuel pump.
>
>
> There a thread here detailing it?

Most of the info at the link below is still valid except I ran out of good quality pumps back in late 2020. I just sell the adapter kits here or there these days because understandably, most people are changing to electric pumps. In the near future, I'll have a cool modification for those who have done the E-pump conversions.
[corvaircenter.com]

Video of my adjustable fuel pressure mod.
[youtu.be]

Dave W. / Gilbert Arizona
65 Corsa 140/4 Butternut Yellow
66 Corsa 140/4 Stinger Tribute
66 Corsa 140/4 w/factory A/C Aztec Bronze
65 Monza 4DR 140/PG w/factory A/C Ermine White
65 Monza 4DR EJ20T/5 Light Metallic Blue

PM sent Dave!

Thanks . . . . Greg

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]

I'd like to check the fuel pressure being put out by the electric pump on the car. My plan is to fill the bowls on all the carbs, without the car running, using the electric pump, and then detach the RH secondary carb and route the fuel line to a pressure gauge temporarily. Then I'll run the car briefly to get an idea of what the pressure looks like. This is, of course, just a temporary setup.

All the fuel gauges I've been able to find have a 1/8" male NPT connection. For me to get from this connection to the flare fitting at the fuel line termination, am I going to want to use an adapter like this (along with a common female-female NPT union):

[www.amazon.com]


I wasn't really sure if the 7/16-24 inverted flare end of this fitting is correct to mate with the fuel line...

Terry

1966 140 Monza PG convertible
Ventura County, CA

Well, on my similar issue on a 140, I went through my carbs with a fine tooth comb today. Found a few small items that needed addressing. Had 2 good hot starts about 20 minutes or so after warming up. 45 minutes later or so it would not start. I can see fuel pooled under LH secondary. I imagine it is also pooled under RH primary - just cannot see well. Looks wet under RH secondary - engine is canted forward, so fuel will run that way in the plenum.

However . . . Just found my fuel pump kit from AZDAVE in the mailbox

Reading up on the install now . . .

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]



Edited 1 time(s). Last edit at 03/19/2023 05:28PM by gerg.

In reading through old threads on carb flooding due to float needle sticking, I came across this:

Also open the secondaries on a 140HP - if not used they will gum up and cause the floats to stick.

[corvaircenter.com]


I would have thought that these 2 carb sub-systems (throttle plates and fuel bowl) would operate independently, so that sticking throttle plates would have no effect on needle valve operation.

Am I missing something?

1966 140 Monza PG convertible
Ventura County, CA

Can anyone recommend a fuel pressure gauge that works well?

There seems to be 2 types: one is liquid-filled and one that is not. The liquid-filled type suppresses needle vibration, but suffers from serious inaccuracy with temperature variation (like in an engine compartment!).

Help.

1966 140 Monza PG convertible
Ventura County, CA

vairTer Wrote:
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> Can anyone recommend a fuel pressure gauge that works well?

I sell a dry gauge along with two brass connectors so they install on the outlet of the pump. Once you have the pressure set, you can remove the gauge and install a plug if you are concerned about having a gauge too close to the fan belt. I leave mine in place but really, once you have set the pressure, it's not something you normally look at everyday. Just like the oil pressure gauge, I check it occasionally at hot idle after a long freeway run and then don't look at it again for months.

I use these parts to add the gauge.


This is where it installs unless you have a turbo setup.


I sell those parts with a gauge for $25 but you can source you own without too much trouble. The gauges I currently offer are shown in the last photo.

Since you are running an E-pump I'm not sure where you would add the gauge (you might have removed the old pump but maybe have a dummy pass-through plate in place) but you can buy the gauge on eBay. I verify the ones I sell to a known standard so I know they are reasonably accurate around 4 PSI.

Dave W. / Gilbert Arizona
65 Corsa 140/4 Butternut Yellow
66 Corsa 140/4 Stinger Tribute
66 Corsa 140/4 w/factory A/C Aztec Bronze
65 Monza 4DR 140/PG w/factory A/C Ermine White
65 Monza 4DR EJ20T/5 Light Metallic Blue

Dave - got your PM and thanks for contributing the way you do to this hobby / culture / obsession

Do you have a short list of expected problems seen when the pressure is too high out of the pump?

I can only logically presume my pump is way high - will know more later today when I finish installing your kit,

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]

I just have a right side line with a 1/8 NPT tee having the pressure gauge. I cut an old line and used flared hose fittings and rubber hose to get it in the line. Since it's for test purposes only I'm not worried about it being hokey. It just goes to the right Primary and nothing to the Secondary.
I have a similar arrangement for a Carter YH between the filter and carburetor. The gauge is just whatever was on the wall at O'Reillys and has been okay so far. I like being able to run the engine and watch the fuel pressure. I had a mechanical pump once that lost pressure after a few miles on the road, not sure why.

Jim Brandberg
Isanti, MN
CorvairRepair.com

So I just finished installing Dave’s kit. I’ll say it is a fine design and Dave is very responsive & helpful.

I adjusted it to read stock height initially and wasn’t too surprised to see it pegging 10lbs when cranked. I dialed it down to 4lbs.

Car idled as long as I let it once warmed up - which it would not do yesterday with fuel spilling over once the pump pressure overcame the needle seats.

I also had to back the idle screws down to get to the 850 idle I wanted to see - I expect I had to open them more yesterday to give air flow to the over rich mixture / spillage? I’ll have to find the sweet spot - this is a PG / AC car.

So far it is MUCH better.

A hot start in about 45 minutes will be the next test.

gerg
Monroe, LA

Current cars and other fun stuff -> [gregblakeney.smugmug.com]

gerg Wrote:
-------------------------------------------------------
> Do you have a short list of expected problems seen when the pressure is too high out of the pump?

If pressure is too high, the first issue is usually fuel dribbling out of the venturi clusters at idle due to the floats not being able to completely close against the pressure. If they do close, the fuel level would still be higher than expected which can cause other issues like running rich. The higher the fuel level in the bowls, the easier it is for the venturi effect to pull fuel out of the bowl and into the engine. Think how easy it is to drink from a straw when your tall iced tea glass is full compared to the effort when the glass is nearly empty.

Even the dreaded "engine bogs in a sharp turn" issue will be worse because the higher fuel levels in the bowl will make it more prone to spill over the bowl vents and down into the carb throat which gives way too much fuel and bogs the engine. Many people think that when the engine cuts out in a hard turn it is because of fuel starvation but it is actually the opposite. That is why the extended bowl vent tube mods works. It makes the vent so tall that the fuel cannot climb that far in a hard turn.

Dave W. / Gilbert Arizona
65 Corsa 140/4 Butternut Yellow
66 Corsa 140/4 Stinger Tribute
66 Corsa 140/4 w/factory A/C Aztec Bronze
65 Monza 4DR 140/PG w/factory A/C Ermine White
65 Monza 4DR EJ20T/5 Light Metallic Blue