Misc Carbs questions

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newtopinz
United States of America
Posts: 62
Joined: Tue Dec 31, 2019 5:59 pm
Location: Monterey Bay area, CA

Misc Carbs questions

Post by newtopinz » Wed Apr 22, 2020 12:04 am

Found out my rear carb was had loose base screws so I decided to attempt a rebuild/repair since the pinz came with the kit. But had a few questions.

1. Have been looking to figure out what is the correct float height. This is what I found front and rear., same height. I believe the manual mentions 16 mm +/- 1mm. So I think this level is too low. The pictures I have found about this and the one included in the gauage tool, I have a hard time telling where the fuel level is at. It has a 1mm shim for the float needle, should I go 0.5mm or no shim at all? Haven't measured it but that metal piece height corresponds to 16mm I take it?
Float gauge.jpg
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2. My float looks to be in decent condition but I bought a couple anyway before disassembly just in case since they don't seem to be too expensive. The new ones are one piece but my current one, the floats moves independently of each other. Seems if one looses buoyancy, it will not be affected too much. Seems like a very interesting design, wondering why the new ones are one piece.

2. Jim L's instructions mentioned two of the base screws are shouldered and they are to be placed essentially on the diagonals. All 8 of my base screws are the same. The front carb screws looks good, but the rears could/should be replaced. EI has the screws but not shouldered, just partially threaded and with a hex socket head. SA has shouldered screws. In both EI and SA website, the parts diagram shows same screws and same part #, but I found on this thread: viewtopic.php?f=12&t=11736&p=87663&hili ... rew#p87663; the only diagram showing two different base screws with two different part #s. Anyone know why that is?

BTW: had the chance to meet with Jim L in real life, not only super helpful with his repair write up but also super helpful and gracious with teaching and answering questions about the Pinz. Stand up guy. Main reason I decided to tackle this is that if I screw it up, I will just send it to him.



3. Is it ok to submerge the whole throttle body into carb chem dip for cleaning? I am aware there are throttle shaft seals, which I was planning to replace also, but I do not want to remove the throttle plate. Those seals are expensive. From the way it looks, it seems there is only one way to install it, anyone know which way that is?

4. After following Jim L's instructions, there are still some screws left in the carbs. These can be left while submerged in the carb chem dip also?

5. One shut off selenoid did not work. Are these worth replacing? I read they just helped shut the engine off because pinz tend to run rich.

6. Read many recommend sanding the mating surfaces to take out warp to allow better seal vs using 2 gaskets as for the cab cover. Any down side to doing both or even just using two gaskets?

7. Took out the plugs to check them out. #2 seems lean, the others seems ok to me, but maybe a little soot/rich? Hoping more experience eye can let me know what they think. Doesn;t make sense to me though as I would anticipate #3 and 4 to be the lean one given those were the ones with loose carbs.
Plug 1.jpg
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Plug 2.jpg
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Plug 3.jpg
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Plug 4.jpg
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Thanks in advance.
Kelvin

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Hotzenplotz
Austria
Posts: 337
Joined: Wed Jan 18, 2012 9:07 am
Location: Vienna, Austria

Re: Misc Carbs questions

Post by Hotzenplotz » Wed Apr 22, 2020 2:07 am

Kelvin

Your float level is way too low. If you cannot remove any shims underneath the float valve, simply bend the center piece of the float to adjust the height.

The NDIX floats consist of two buoyancing elements, which have to move independently. Purpose is to keep the fuel level correct as the lower of these two elements determines the fuel level.If the spares you got dont move independently, there is something wrong.

In the German forum I have shown nuts for the base screws that look better to me. They have the M8 thread , but metric keysize 10, so you can propery tighten them.
https://pinzforum.kiruna.de/viewtopic.p ... 64#p105788

If you want to clean the throttle body in an ultrasonic cleaner, disassemble the whole shebang. The seals for the shaft are radial seals and have to be installed with the flat side facing outwards.

The shut off solenoids are off by default. The cylinder with the defective one does not get any fuel....

I use to place fine sand paper on a marble plate and get a flat surface for the matin pieces. Single asket is sufficient. Obviously you have to remove all protruding components.

Hope that helps you plan the next steps
Cheers
Albert
========================
My Pinz has NEVER been with any army

newtopinz
United States of America
Posts: 62
Joined: Tue Dec 31, 2019 5:59 pm
Location: Monterey Bay area, CA

Re: Misc Carbs questions

Post by newtopinz » Sat Apr 25, 2020 4:37 am

Thank you Albert for your response.

I opened the shaft ends and found only remnants of them on one throttle body, none on the other. From what I can see, it seems they were installed with flat side facing the throttle plate. I want to confirm that it is suppose to be facing away from the throttle plate? These seals are the most expensive seals-to-size ratio I've ever seen.
Worn shaft seal.jpg
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worn shaft seal 2.jpg
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Shaft seals.jpg
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The base screws I was speaking of are the screws that attaches the throttle body to the float body. I think the metric nut you speak of I believe is for the screws from the manifold to the throttle body. As far as I can tell, those are working fine. The picture from SAV shows the shouldered screw which I think I'll just get a set of four and use two on each carb as Jim L recommends.
Shouldered screw.jpg
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Carb worn screws.jpg
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How fine of a sand paper grit for flattening the gasket surfaces? 220 enough or up to 400 or even 600?
The gaskets between the manifold and throttle body and also throttle body and float body is super thick, do these surfaces need to be sanded down as well? How about the choke plate surface?

Thanks
Kelvin

newtopinz
United States of America
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Joined: Tue Dec 31, 2019 5:59 pm
Location: Monterey Bay area, CA

Re: Misc Carbs questions

Post by newtopinz » Sat Apr 25, 2020 4:43 am

These are the floats by the way. Bottom is new. New floats from either EI and SAV look identical to me from their website. I think I'll just take the black rubber/plastic parts off the new one and put it on the metal portion of the old float, unless it is better just to use the old one again. They seem to be in working condition, no rattles or sloshing/fluid inside.
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Floats.jpg
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Hotzenplotz
Austria
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Location: Vienna, Austria

Re: Misc Carbs questions

Post by Hotzenplotz » Sat Apr 25, 2020 6:38 am

Kelvin

The finer the sanding paper you use, the better the result.
When I redid my carbs I sanded all mating surfaces, i.e. head to body, body to throttle assy and choker.
you correctly identified the location of the metric nuts I mentioned.

I used philips head screws M6 x 40 to connect throttle assy to main body, and secured them with loctite medium. This allows for the use of a torque wrench.

For the shaft seals I strongly recomment you remove the shaft and clean yout the mess in there. The seals have to me installed like any circular seal, flat side out so the pressurefrom the inside helps tp press the rubber against the shaft. Same orientation is used at e.g. crankshaft, portal axle, ...

When you reinstall the butterfly disks into the throttle assembly , sand the disks on both sides before you install them, and secure these tiny screws with loctite, too.

re floats: the ones with the independently moving bodies are the preferred solution. going uphill the fuel level is determined by the lower , i.e. rear float body. if you use the connected floats you might get a shortage of fuel
Cheers
Albert
========================
My Pinz has NEVER been with any army

newtopinz
United States of America
Posts: 62
Joined: Tue Dec 31, 2019 5:59 pm
Location: Monterey Bay area, CA

Re: Misc Carbs questions

Post by newtopinz » Sat Apr 25, 2020 10:55 am

In the operating environment for the throttle, wouldn't the positive pressure, atmospheric pressure in this case, be on the outside versus the vacuum within the throttle body. As such, with the design of the radial seal, seem flat side would be facing in so that the atmospheric pressure, which is higher will help with induce seal.
Portal and crankshafts does not deal with relative vacuum environment as far as I know.

Am I thinking this too much?

Tjerk
South Africa
Posts: 22
Joined: Sat Jun 23, 2018 3:48 am

Re: Misc Carbs questions

Post by Tjerk » Sat Apr 25, 2020 11:13 am

Sharp side to what you want to keep out and that includes dust!
Tjerk ZS1J

boeing7873
Argentina
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Re: Misc Carbs questions

Post by boeing7873 » Sat May 23, 2020 8:43 pm

Where did you find those shaft seals?
One of my carbs leaks a little through the front end...
Jerome
CRJ Driver

newtopinz
United States of America
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Joined: Tue Dec 31, 2019 5:59 pm
Location: Monterey Bay area, CA

Re: Misc Carbs questions

Post by newtopinz » Sat May 23, 2020 10:59 pm

Swiss army vehicles.

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