NDIX Carb Mixture

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Garrycol
Australia
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Location: Canberra Australia

NDIX Carb Mixture

Post by Garrycol » Sun Jul 14, 2019 11:46 pm

On the NDIX carb, idle mixture can be adjusted via the idle mixture screws at the front of the carb. Mixture throughout the rest of the rev range is determined by fixed jets which have to be changed out if changes to the mixture are needed.

My engine is running rich, no choke needed to start on cold mornings, black soot in the exhaust pipe etc - though is not rich enough to actually blow visible black smoke.

So what else in the carb can cause the carb and engine to run rich?

PS - choke on the carb opens fully when pulled on and closes fully when the control is pushed in.
Thanks

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

Jim Molloy
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Re: NDIX Carb Mixture

Post by Jim Molloy » Thu Jul 18, 2019 2:28 pm

Garry,
Do your spark plugs look sooty as well and are they equally effected?
Jim Molloy
Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

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Garrycol
Australia
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Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Thu Jul 18, 2019 8:56 pm

Hi Jim - yes they are also sootie. Have changed the coil, put in new plugs, temporarily removed the pertronix and went back to points and re-timed and the new plugs sooted up almost immediately. The plugs do have good spark though.

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

Jim Molloy
United States of America
Posts: 239
Joined: Sun May 30, 2004 2:16 pm
Location: Sheridan, Oregon
Contact:

Re: NDIX Carb Mixture

Post by Jim Molloy » Sat Jul 20, 2019 5:14 pm

Garry,
Is your Haflinger equipped with the small cyclone pre-cleaner between to two scuttle vents on the nose of the truck? If no carburetor adjustment has been made but the air/fuel ration is now universally rich, the only thing that comes to mind is reduced air flow upstream from the carburetor venturis. Have you tried new plugs but with the air intake system disconnected from the throat of the carburetor? If you have and it is still sooty, a relative deficit of air is ruled out and a relative overabundance of fuel would be the cause. Do you have a Weber or Zenith carb? The floats on the Weber are known for perforating causing rich/flooded conditions. Far less common with the Zenith but I have seen it happen.
Hope this helps.
Take care.
Jim Molloy
Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

Jim Molloy
United States of America
Posts: 239
Joined: Sun May 30, 2004 2:16 pm
Location: Sheridan, Oregon
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Re: NDIX Carb Mixture

Post by Jim Molloy » Sat Jul 20, 2019 5:16 pm

STUPID ME!!!
Of course you have the Zenith NDIX!
Lots on my mind right now.
The float could still be the problem.
Take care.
Jim
Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

Heinkeljb
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Re: NDIX Carb Mixture

Post by Heinkeljb » Sun Jul 21, 2019 4:29 am

Just a thought,

How restrictive is your exhaust system? You could buy a "colortune" kit which has a special spark plug with a clear window in it to allow you to see the colour of the combustion flame, and then obviously to see what happens when you make adjustments.

John

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Garrycol
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Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Sun Jul 21, 2019 7:00 am

Jim Molloy wrote:
Sat Jul 20, 2019 5:14 pm
Garry,
Is your Haflinger equipped with the small cyclone pre-cleaner between to two scuttle vents on the nose of the truck? If no carburetor adjustment has been made but the air/fuel ration is now universally rich, the only thing that comes to mind is reduced air flow upstream from the carburetor venturis. Have you tried new plugs but with the air intake system disconnected from the throat of the carburetor? If you have and it is still sooty, a relative deficit of air is ruled out and a relative overabundance of fuel would be the cause. Do you have a Weber or Zenith carb? The floats on the Weber are known for perforating causing rich/flooded conditions. Far less common with the Zenith but I have seen it happen.
Hope this helps.
Take care.
Jim Molloy
I just run the paper air cleaner and have new plugs. This issue has "just" occurred so unlikely the float level in the Zenith has just changed. I did have issues with the floats separating and the engine flooding big time when I first put the car on the road but new floats from Jim sorted all that.

I do keep coming back to fuel getting into the system somehow and that is in the carb somewhere. Maybe a fresh rebuild and go from there.

Cheers

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

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Garrycol
Australia
Posts: 387
Joined: Sat Oct 06, 2012 6:49 am
Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Sun Jul 21, 2019 7:10 am

Heinkeljb wrote:
Sun Jul 21, 2019 4:29 am
Just a thought,

How restrictive is your exhaust system? You could buy a "colortune" kit which has a special spark plug with a clear window in it to allow you to see the colour of the combustion flame, and then obviously to see what happens when you make adjustments.

John
Same exhaust so no change there - those "colourtune" kits are a bit expensive to buy here for a one off use but I think my neighbour has one so will check with him.

Cheers

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

Jim Molloy
United States of America
Posts: 239
Joined: Sun May 30, 2004 2:16 pm
Location: Sheridan, Oregon
Contact:

Re: NDIX Carb Mixture

Post by Jim Molloy » Sun Jul 21, 2019 10:05 am

Garry,
Once upon a time, I saw a unique NDIX float that allowed each side to function independently. It may have been a variant on a Pinzgauer as I have never seen them on any Porsche 356, Unimog 404, DKW Munga or S-P Haflinger carburetors. In theory, even if one float was full of fuel, the buoyancy of the intact side functioning independently would be enough to close off the float bowl needle valve.

It does sound like it is time to dig into the carburetor. Likely something simple. Best wishes for a rapid recovery of normal function.

Take care.
Jim
Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

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Garrycol
Australia
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Joined: Sat Oct 06, 2012 6:49 am
Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Sun Jul 21, 2019 9:15 pm

Thanks Jim and John - I appreciate your input. Time to pull the carb down and put a kit through it.

Cheers

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

User avatar
Garrycol
Australia
Posts: 387
Joined: Sat Oct 06, 2012 6:49 am
Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Tue Jul 30, 2019 12:43 am

Up to now the engine would run - just not well. Last week it was difficult to start but finally did but ran very poor. On checking the cylinder on the right hand side was cold indicating the engine had just been running on one cylinder. Some sort of ignition problem.

Today I needed to move the Haflinger out of the garage - it would fire but not run - the coil is working as it fires the tacho via an inductive pickup on the HT lead and the tacho was working. I have just received new dizzy cap, rotors, points and condensors so I put them on but the engine still would not fire.

Out with the near new spark plugs (NGK B7HS) and of course they were all carboned up. I had only recently put them in as the last set that were also near new had failed - they were arcing deep down inside and not across the electrode. I cleaned up the plugs I had and one was then fine and the other was firing but also arcing deep down with the plug. I assume the carbon (from the rich mixture) deep down in the plug is providing the short. I put these two cleaned plugs back in and the engine fired up first time and ran really well.

So I am still with my original thought that the carb is too rich and this is carboning up the plugs causing them to fail - hence the problem sometimes seems to be ignition related. I wonder whether in addition to the rebuild kit I am going to put through the carb whether I should also get new main jets etc. I have new idle jets.

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

Jim Molloy
United States of America
Posts: 239
Joined: Sun May 30, 2004 2:16 pm
Location: Sheridan, Oregon
Contact:

Re: NDIX Carb Mixture

Post by Jim Molloy » Tue Jul 30, 2019 10:41 am

Garry,
Is there anyone reasonably close with a running Haflinger that would allow a temporary carburetor swap? That would allow you to isolate the problem more specifically.
Best wishes.
Jim Molloy

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Garrycol
Australia
Posts: 387
Joined: Sat Oct 06, 2012 6:49 am
Location: Canberra Australia

Re: NDIX Carb Mixture

Post by Garrycol » Wed Jul 31, 2019 6:51 am

Unfortunately no. I have had my Haflinger for 7 years and in that time I have not ever seen another one on the road and only sighted another one once parked in a yard 300km away - even the local carb rebuilders do not know the Zenith NDIX.

I am afraid I live in an automotive backwater. I do have a mechanic that works on older vehicles and he has a dyno and all the electronic test gear so I might just hand it over to him and say "fix" - clearly in its simplest form a readout of fuel air ratio should inform of the mixture.

I do have a wide band O2 sensor and gauge so I could use that but it would need a modification to the exhaust to mount to O2 sensor - probably easier to give it to the mechanic and let him a probe up the exhaust and take it from there.

I was hoping that as the Pinz and early Mogs use the same carbs there might have been some experts on the forum with relevant experience.

Cheers

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

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