NDIX Carb Mixture

[AustHaflinger]

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

[heinkeljb]

Blocked air filter?
Worn jets ? ( think Grand Canyon on a smaller scale, how old are the jets?)

Those are the usual culprits Gary.

John

[AustHaflinger]

Thanks John - I deleted your second post - air filter is new and the jets age is anyone's guess. I don't think it would be the jets as they are just holes in brass with no needles to wear them unless someone has been poking them with something and that someone has not been me.

I was thinking along the lines of internal carb fuel leaks that allows fuel to bypass the jets and go straight into the engine - maybe a float valve too high type issue (not likely but possible) - what about the accelerator pump - can it pump more than it should or can it leak letting fuel past it?

[heinkeljb]

Hi Gary,

Jets wear just because fuel flows through them, obviously not huge amounts, but could be enough to alter the mixture.
Other items you mention are also items which can and do let more fuel in than needed. Most likely is the float but usually that lets in so much your engine chokes and runs really rough.

Accelerator pump should not allow fuel past, but might if the plastic piston is worn and you have a very high vacuum, I.e. foot flat on the floor going up hill. Accelerator pump is far more likely to give you a flat spot when you put your foot down suddenly when wornas it won’t lift as much fuel as it should.

As you drive mostly in town where there is not so much dirt, you could try running with out the air filter to see if that makes a difference to your plugs.

As your engine is bored, maybe the guy who set it up opted for richer rather than leaner jets whilst running in?

John

[AustHaflinger]

Thanks for your comments.

When the mods were originally done it ran a non haflinger carb - a Solex 34b which was problematic so I replaced it with a 32 NDIX. However I was not able to buy a Haflinger unit so bought a used Unimog 404 unit from the US. I was not able to buy a set of correct jets but was able to buy a Haflinger jet block (the middle section of the NDIX carb) from Haflinger Technik and put it in - so the bottom section of my carb is Unimog, the middle section with the jets is Haflinger and the top section is Unimog.

I then had the composite carb rebuilt by a carb specialist with all new gaskets, accelerator pump etc and other than a minor issue where the floats fell apart soon after rebuild, it has provided stirling service for the past 5 years and all of a sudden is not working as well as it was.

I have a new extensive kit that I can put in but it was not cheap so do not want to use it unless I have too - so I really want to be assured it will solve the issue I have as the Haf has only covered 4000km since the big rebuild 5 years back.

I have also posted the same question on the Real 4x4 forum as most of the relevant vehicles over there use the carb but they seem to rarely discuss Haflinger related issues.

Garry

[heinkeljb]

Unfortunately Real4x4 is mainly American and is more devoted to Pinzgauer’s. Also there are fewer Haflinger’s in America.
I have noticed that the people who have real knowledge of Haflinger’s are obviously the older generation and they are mostly technophobes so do not join forums like this or post on them.
I would suggest you dismantle the carb and clean it. If you can get hold of an ultrasonic cleaner then so much the better, even a bowl full of clean petrol and a can of compressed air would do.

A really good clean might solve your issues.

John

[AustHaflinger]

Yes that is likely to be action I will have to do - I cleaned it all out before Christmas last year but it might need doing again.

Cheers

Garry

[AustHaflinger]

Unfortunately Real4x4 is mainly American and is more devoted to Pinzgauer’s. Also there are fewer Haflinger’s in America.
I have noticed that the people who have real knowledge of Haflinger’s are obviously the older generation and they are mostly technophobes so do not join forums like this or post on them.

Yes I am surprised at the US site and their non action on Haflinger posts. As far as the carb goes it is the same as is on the Pinz and older Unimogs so questions are often relevant to to their vehicles as well as Haflingers. Same applies to dynastarters as well as other aspects.

You are correct about some people wanting to keep knowledge and no share it - this has been discussed on this forum a few years back. There are a lot of people out there who have a great deal of information and just do not share it when people post up issues they are having.

While there are people on our forum from North America, the UK, Australia and a few other places, the bulk of Haflinger ownership in the world resides in Germany, Switzerland and Austria (as evidenced by the number of Haflinger Youtube videos from people from that part of the world), yet we (and Real 4x4) virtually have no members from that part of the world to contibute to the knowledge base. I guess they have their own closed social media information sharing groups that do not get visibility when you Google Haflinger forums etc.

Anyway - my thoughts anyway.

Garry

[AustHaflinger]

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.

Any one know where to buy new jets and what ones are important to replace? As the engine starts and idles OK and it would seem Rich when driving around I assume just the main jets and air correction jet.
The main jets are 110
Air correction jet is 240
Idling is 45
Idling air jet is 80 and
Starter is 190

Garry

[AustHaflinger]

To finish this up.

Late last year I serviced the car and it has not run well ever since - basically the engine was running too rich and after a couple of days the plugs would carbon up with no spark. After cleaning the plugs the engine would start etc but soon again the plugs would carbon back up.

It took a while to work out that the issue was not ignition - proved by replacing everything on the ignition side.

So enough was enough - so I started all over again.

Reset the tappets - inlets were OK, one exhaust had no clearance but not tight and the other exhaust was overly loose - all reset not issues. It is just tight doing the exhausts maybe that is why they were not right.

I had bought a new carb kit - for a Porsche 365 - was quite expensive but did include a new accelerator pump and fuel float level valve as well as the usual gaskets etc.

I pulled the the carb down and all seemed fine - the accelerator pump rubber seemed a little perished and the fuel float level valve also seemed fine - I just reassembled with the new pasts and gaskets. The float level in the carb is not adjustable as such and if you wanted to change it the only way would be to put a dob of solder on the float arm or space out with thicker washers where the valve screws into the housing making the valve sit lower in the fuel chamber so the fuel level is lower. The washer in my carb was a thin fibre one where the kit had a thicker aluminium one so I used that one.

Any way all reassembled and she fired up straight away and seemed to rev OK. Prior to this rebuild the engine would start ok but within a couple of km the engine starts to play up as the plugs carbon up.

The drive today was completely different - no missing, seemed to have full power and when I got back I pulled the plugs and all good - no longer carboned up.

So I covered 35km, reached a top speed of 86.8kph and averaged 52.2kph without any real issues.

I suspect the issue was fuel leaking past the accelerator pump causing the carb to run rich.

Hopefully all good from here.

Garry

[heinkeljb]

Well done, it some times pays to go back to the beginning and start again.

John

[AustHaflinger]

Yes = what has prompted this current work is my everyday driver has to go into the smash repairer for a week of minor repairs where some Muppet ran in the back of me - so I need the Haf to drive around in while the car is off the road.

Now that the engine is running OK, I will put the Pertronix electronic ignition back in the distributor. Oh I also set the ignition at 10 degrees BTDC and seems to work fine - temps are good and cannot hear any pinging.

[wojo12]

I will put the Pertronix electronic ignition back in the distributor.

Garry, I'm thinking of converting my Haf to electronic ignition - what model is your Pertronix kit?

Cheers

[AustHaflinger]

I am not sure of the exact model number but this is what I have got.

https://expedition-imports.com/mv121

Garry

[wojo12]

I am not sure of the exact model number but this is what I have got.

https://expedition-imports.com/mv121

Garry

The Oz distributor of Pertronix have not heard of a MV121, and of course my dizzy model number is not visible currently!! Foiled again.

[AustHaflinger]

Just buy from Expedition Exports. That MV part number is probably the Expedition Exports part number not the Ignitor number.

[AustHaflinger]

To finish this up.

Reset the tappets

I had bought a new carb kit

The accelerator pump rubber seemed a little perished and the fuel float level valve also seemed fine. The float level washer in my carb was a thin fibre one where the kit had a thicker aluminium one so I used that one.

Any way all reassembled and she fired up straight away and seemed to rev OK.

The drive today was completely different - no missing, seemed to have full power and when I got back I pulled the plugs and all good - no longer carboned up.

I suspect the issue was fuel leaking past the accelerator pump causing the carb to run rich.

Hopefully all good from here.

Garry

To finish once again.

While the car was running al lot better it would miss going up hill and became difficult to start - sometimes plugs would carbon up and other times were fine.

Had enough and booked it into my local mechanic to fix it - they have a dyno and tune it on there.

Picked it up today - wow what a difference - smooth as all round.

Issues found - carb seems ok but at high revs is running rich - I guess better rich rather than lean but it would be nice correct. He measured all jets and all meet specs. Maybe my height of 650m above sea level is the issue - but not worth pursuing at this time but when the carb is next off I will check what number high speed jets I have.

I put in the new washer for the float valve but it was too thick (1.5mm) and at high revs the float chamber was emptying - fixed with a thinner washer.

Tappets were all over the shop again - but nothing to cause issue - these really needs checking with each service.

Timing is set at 10 BTDC and and as the mech said makes the engine run really crisp.

Points were a bit open too much - too much twell.

The issue was the coil - he said as soon as the engine went on the electronic tuner it was obvious that the secondary coil was breaking down. Now this is a brand new coil and only covered a few hundred kms - I have recommended the Bosch GT40 coil on this forum as I have used it in a number of vehicles over many years - however Bosch now make this coil in China and they are failing. The mechanic had the Bosch rep in his garage the day before my Haf went in where it was explained the GT 40 coils are now crap - were very good before.

So out with the GT40 in with a

On the dyno the Haf produced 15hp at the back wheels.

So it is amazing what an expert with high tech equipment can do. In future when it is time for a tune up - I will just send it back rather than trying to sort it myself.

Garry

[heinkeljb]

Wow! I knew the drive train of a Haf took a lot to turn, but leaving you with 15 hp to get any ting else done is obviously why they die going up hills!
Still, nice to know you have it running nicely again. Reminds me I need to do a service on Lurch for the winter. The “new” engine is currently running 20w50 and that it too thick when trying to start some mornings to the point where the Dynastart won’t even turn the engine over.

John

[AustHaflinger]

Wow! I knew the drive train of a Haf took a lot to turn, but leaving you with 15 hp to get any ting else done is obviously why they die going up hills!

And the mechanic was surprised it made that much

The other thing he noticed is that the exhaust pipe on the standard small haflinger muffler is too small. He said the piping from the engine and muffler and tail pipe should be about the same size as the exhaust from one bank (not the equivelent of of the cross section of both exhaust ports. In his view the muffler etc is providing too much back pressure - so basically he believes the entire exhaust system pipe diameter should be the same size as the standard exhaust manifold - as it is the Haf muffler and tail pipe is only 2/3rd the size of the of the pipe from the exhaust manifold to the muffler.

I might look at this.

Yes 20W50 is too thick for a new engine - ok for an engine with 200,000km on it that is becoming a bit loose but far too thick for a new engine - something with a 40 as the top number would be better. My Range Rover Sport runs 5W30 and it has 180,000km on it. I put 15W40 in my Haflinger - hotter here than where you are in summer and winter temps would be similar - I did try synthetic oil but the engine did not like it so I stay with full mineral oil.

Garry

[AustHaflinger]

So after getting the Haf back on Thursday - I filled up with fuel and went for a 23km test run - all good - top speed 87.5kph and average was 52kph. Yesterday, did 68km and top speed was 87.8kph and average was 60kph.

As all seemed good decided to take a long drive in the country - 91km but tried to stay at my normal cruising speed of 70kph and 4000rpm - the engine seems to like these revs. Max speed was a more realistic 76kph and averaged 53kph.

The car ran perfect so it seems all is good now.

It is amazing when you drive at a slower speed and in a vehicle like a haflinger you sense the environment a bit more - you notice the particularly Australian smell of decaying dead roo in the 35c sun, spotted numerous live ones as well, a couple of emus trying to steal sausages off BBQ plates at the picnic ground, a couple of red belly black snakes slithering out of your way after sun baking on the road, a couple of galahs almost planted on the windscreen and and a long neck turtle in the middle of the road trying to get across - most of these would have been missed in my daily driver.

Fuel consumption is now improved and I will now get about 230-250 km between fills giving a fill to empty range of just under 300km.

So hopefully all stays well for a while.

Garry