Amazon: - Freshly rebuilt Zenith with some concerns - Page 3

Derek UK · May 21st, 2023, 08:56

The little ball you can see in the hole adjacent to your red circle is made of lead. These holes are drilled for the internal routes for fuel. The lead ball is tapped in to reseal the hole. It's common for these to weep a bit but on a newly refurbed carb should be OK. It is a bit unpredictable.

I have your mail and should get the brake manual to this evening. Will send the other manual parts too,

samaron · May 21st, 2023, 11:50

The fuel is seeping out of from the shaft hole, not the plugged ones. The carburetor has an internal leak somewhere, and the fuel that collect on the flap slowly comes through the tiny clearance for the shaft. Assuming this is abnormal.

I remember having a very hard time getting the gasket for the emulsion block to seal when I attempted my rebuilds. This would allow fuel to leak past it and drip from the discharge beak, or just run down the side. The result from my side was commissioning someone to make a custom gasket that would compress slightly more to fill in the tiny gaps.

Going for a drive now and pull off the air cleaner assembly to attempt to identify where it is coming from.

samaron · May 21st, 2023, 13:41

Had a drive now and pulled off the air cleaner while the engine was running. Everything looked fine. I shut it off and immediately it started dripping from the discharge beak. This video is filmed maybe 2 minutes after shutting off the engine. Attempted to take pictures first, which didn't turn out the way I intended.

Looking at the reflection on the beak, it seems fuel collect around it and drips rather than from the passage. Hard to see exactly, however.

I can add that I tested the float needle multiple times before installation. Were blowing into it while turning the carburetor. Pumping on the fuel pump I can feel and hear it close as it should. Have not had any trouble the past couple of weeks with it sticking open or closed.

EDIT:
Here is a different video showing while it is running and when it is turned off. You can see the top of the beak start to shine as it gets wet with fuel. Towards the end you can see some fuel start to creep up between the venturi tube and body. I believe the emulsion block inside the float bowl does not seal, allowing fuel to leak past.

Found a military vehicle supplier that sell loose parts for 36 VN models used on B18. Ordered a new float bowl, as the bowl surface is probably distorted in some way. I probably should contact the company and have it returned again, but its just taking too long.

Rustinmotion · May 21st, 2023, 15:52

Have you checked fuel pressure? If it’s too high it can overcome the needle valve, might not be an issue when engine running but once shut off it could give same symptoms, for sure it should not be doing that
Try hooking up a simple gravity feed direct to carb with no pump does it do it then?
I’d be looking at needle valves and fuel pressure

142 Guy · May 21st, 2023, 16:15

That is truly unusual.

With the way that raw gas is flowing out after engine shut down it is not a surprise that you had some hot restart problems. Aside from the gas outside the carburettor and the hot restart problem, I would be concerned about that raw gas if the shape of the intake manifold is such that it can flow into the cylinders. That gas can wash oil off the cylinder walls leading to accelerated wear on start-up.

My knee-jerk reaction is similar to Rustinmotion's suggestion that you have excessive fuel pressure or perhaps the fuel level in the bowl (float setting) is too high. On shut down, if you carefully disconnect the fuel line from the carb releasing supply pressure does that eliminate the drip? I would normally suggest a fuel pressure gauge to confirm fuel pressure; but, I do not know what the pressure limits are for that particular carb. If the drip disappears after a few minutes, that could be because the fuel pressure has dropped or it could be that the fuel level has dropped below the problem level (whatever that problem level is) in the bowl.

In retrospect, the best course of action might be to send a copy of that video to the company that provided the rebuilt carb and ask them if they know what is going on and what the possible remedies might be.

samaron · May 21st, 2023, 18:03

The entire fuel system is more or less brand new. Fuel tank, fuel pump, fuel lines etc. I even have an additional fuel filter inline before the pump. No sign of any debris getting collected so far.

The fuel pump is the original glass bowl style. I find it hard to believe it would have too high fuel pressure? I could disconnect the fuel line and observe inside the carburetor if it stops dripping.

The float valve was checked multiple times before assembly. I blew into the inlet while turning the carburetor. Had issues with it sticking open or closed all the time prior to the rebuild. I wanted to make sure it at least was functioning as intended. Pumping fuel I could hear the float bowl fill up and eventually the valve would close. This could also be felt on the pump lever. If it was sticking open, wouldn't it be natural that fuel would come out the ventilation holes as a result? When the valve was sticking open before, it would gush out.

Hooking up a gravity feed might be a bit challenging. The carburetor does not have hose connections. I have to either find hoses with a large inner diameter or find someone with appropriate adapter fittings for sale.

I assume the drips stop after a while. As mentioned, I have no trouble starting the car the next day. Fuel is still present in the bowl.

Also a bit disappointing that I shouldn't drive the car until this is resolved. It has been out of comission for several months at this point. I'm certainly hesitant to the idea of returning the carburetor for rework yet again.

Rustinmotion · May 21st, 2023, 20:08

It’s hard to see but are the fuel lines steel? That makes it harder to play around, I know you can get too much fuel pressure if the shim between block and fuel pump is not installed

samaron · May 21st, 2023, 20:31

Yes, everything is steel and brass.

Digging around in a box of parts I were given at some point, I found a piece of cut fuel line with an approriate fitting and flare. Looks like I should be able to MacGyver a hose connection with that, if I can find some hose with matching inner diameter.

samaron · May 22nd, 2023, 11:47

Spent some time doing some further testing today. Got a bit creative and got a boat tank with a primer hand pump on the fuel line.

Running the car and stopping it still results in an immediate fuel leak into the intake, with the pump connected. Cracking open the fuel line on the pump outlet causes some fuel to squirt out and the carburetor leak stop after a few seconds.

Hooking up a pressure gauge on the fuel pump outlet, I get a pressure reading of just over 6 psi. See attatched picture. Doesn't appear to be excessive?

Disconnecting the pump inlet and running the car from the boat tank results in no leak. See attatched picture and video. Being honest... I initially forgot to disconnect the inlet and made a mess.

https://www.youtube.com/watch?v=2x0EjDZ22Xk

Derek UK · May 22nd, 2023, 13:18

I think your float is set too high and this allows fuel to leak from the beak. Needle valve uses different thickness washers to set the float height. 3 different ones supplied with a new needle valve.
Fuel leaking into the inlet manifold will hamper hot starts until it is cleared.

I have sent you a mail.

May 21st, 2023, 11:50	#22
samaron Member Last Online: Jan 15th, 2024 22:45 Join Date: Jan 2023 Location: Norway	The fuel is seeping out of from the shaft hole, not the plugged ones. The carburetor has an internal leak somewhere, and the fuel that collect on the flap slowly comes through the tiny clearance for the shaft. Assuming this is abnormal. I remember having a very hard time getting the gasket for the emulsion block to seal when I attempted my rebuilds. This would allow fuel to leak past it and drip from the discharge beak, or just run down the side. The result from my side was commissioning someone to make a custom gasket that would compress slightly more to fill in the tiny gaps. Going for a drive now and pull off the air cleaner assembly to attempt to identify where it is coming from. __________________ 1958 Amazon 4-door saloon

May 21st, 2023, 13:41	#23
samaron Member Last Online: Jan 15th, 2024 22:45 Join Date: Jan 2023 Location: Norway	Had a drive now and pulled off the air cleaner while the engine was running. Everything looked fine. I shut it off and immediately it started dripping from the discharge beak. This video is filmed maybe 2 minutes after shutting off the engine. Attempted to take pictures first, which didn't turn out the way I intended. Looking at the reflection on the beak, it seems fuel collect around it and drips rather than from the passage. Hard to see exactly, however. I can add that I tested the float needle multiple times before installation. Were blowing into it while turning the carburetor. Pumping on the fuel pump I can feel and hear it close as it should. Have not had any trouble the past couple of weeks with it sticking open or closed. EDIT: Here is a different video showing while it is running and when it is turned off. You can see the top of the beak start to shine as it gets wet with fuel. Towards the end you can see some fuel start to creep up between the venturi tube and body. I believe the emulsion block inside the float bowl does not seal, allowing fuel to leak past. Found a military vehicle supplier that sell loose parts for 36 VN models used on B18. Ordered a new float bowl, as the bowl surface is probably distorted in some way. I probably should contact the company and have it returned again, but its just taking too long. __________________ 1958 Amazon 4-door saloon Last edited by samaron; May 21st, 2023 at 15:26.

May 21st, 2023, 18:03	#26
samaron Member Last Online: Jan 15th, 2024 22:45 Join Date: Jan 2023 Location: Norway	The entire fuel system is more or less brand new. Fuel tank, fuel pump, fuel lines etc. I even have an additional fuel filter inline before the pump. No sign of any debris getting collected so far. The fuel pump is the original glass bowl style. I find it hard to believe it would have too high fuel pressure? I could disconnect the fuel line and observe inside the carburetor if it stops dripping. The float valve was checked multiple times before assembly. I blew into the inlet while turning the carburetor. Had issues with it sticking open or closed all the time prior to the rebuild. I wanted to make sure it at least was functioning as intended. Pumping fuel I could hear the float bowl fill up and eventually the valve would close. This could also be felt on the pump lever. If it was sticking open, wouldn't it be natural that fuel would come out the ventilation holes as a result? When the valve was sticking open before, it would gush out. Hooking up a gravity feed might be a bit challenging. The carburetor does not have hose connections. I have to either find hoses with a large inner diameter or find someone with appropriate adapter fittings for sale. I assume the drips stop after a while. As mentioned, I have no trouble starting the car the next day. Fuel is still present in the bowl. Also a bit disappointing that I shouldn't drive the car until this is resolved. It has been out of comission for several months at this point. I'm certainly hesitant to the idea of returning the carburetor for rework yet again. __________________ 1958 Amazon 4-door saloon

May 21st, 2023, 20:31	#28
samaron Member Last Online: Jan 15th, 2024 22:45 Join Date: Jan 2023 Location: Norway	Yes, everything is steel and brass. Digging around in a box of parts I were given at some point, I found a piece of cut fuel line with an approriate fitting and flare. Looks like I should be able to MacGyver a hose connection with that, if I can find some hose with matching inner diameter. __________________ 1958 Amazon 4-door saloon

May 21st, 2023, 08:56	#21
Derek UK VOC Member Last Online: Yesterday 15:13 Join Date: Jul 2006 Location: Chatham	The little ball you can see in the hole adjacent to your red circle is made of lead. These holes are drilled for the internal routes for fuel. The lead ball is tapped in to reseal the hole. It's common for these to weep a bit but on a newly refurbed carb should be OK. It is a bit unpredictable. I have your mail and should get the brake manual to this evening. Will send the other manual parts too,

May 21st, 2023, 15:52	#24
Rustinmotion Senior Member Last Online: Yesterday 14:45 Join Date: Sep 2021 Location: MILTON KEYNES	Have you checked fuel pressure? If it’s too high it can overcome the needle valve, might not be an issue when engine running but once shut off it could give same symptoms, for sure it should not be doing that Try hooking up a simple gravity feed direct to carb with no pump does it do it then? I’d be looking at needle valves and fuel pressure

May 21st, 2023, 16:15	#25
142 Guy Master Member Last Online: Apr 27th, 2024 15:46 Join Date: Jul 2020 Location: Saskatchewan, Canada	That is truly unusual. With the way that raw gas is flowing out after engine shut down it is not a surprise that you had some hot restart problems. Aside from the gas outside the carburettor and the hot restart problem, I would be concerned about that raw gas if the shape of the intake manifold is such that it can flow into the cylinders. That gas can wash oil off the cylinder walls leading to accelerated wear on start-up. My knee-jerk reaction is similar to Rustinmotion's suggestion that you have excessive fuel pressure or perhaps the fuel level in the bowl (float setting) is too high. On shut down, if you carefully disconnect the fuel line from the carb releasing supply pressure does that eliminate the drip? I would normally suggest a fuel pressure gauge to confirm fuel pressure; but, I do not know what the pressure limits are for that particular carb. If the drip disappears after a few minutes, that could be because the fuel pressure has dropped or it could be that the fuel level has dropped below the problem level (whatever that problem level is) in the bowl. In retrospect, the best course of action might be to send a copy of that video to the company that provided the rebuilt carb and ask them if they know what is going on and what the possible remedies might be.

May 21st, 2023, 20:08	#27
Rustinmotion Senior Member Last Online: Yesterday 14:45 Join Date: Sep 2021 Location: MILTON KEYNES	It’s hard to see but are the fuel lines steel? That makes it harder to play around, I know you can get too much fuel pressure if the shim between block and fuel pump is not installed

May 22nd, 2023, 13:18	#30
Derek UK VOC Member Last Online: Yesterday 15:13 Join Date: Jul 2006 Location: Chatham	I think your float is set too high and this allows fuel to leak from the beak. Needle valve uses different thickness washers to set the float height. 3 different ones supplied with a new needle valve. Fuel leaking into the inlet manifold will hamper hot starts until it is cleared. I have sent you a mail.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)