Number 1 Carb issue.

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Buzz
United States of America
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Location: Jacksonville, Fl.

Number 1 Carb issue.

Post by Buzz » Mon Feb 01, 2021 7:46 pm

I been having issues with engine performance when accelerating away from a stop and on the highway. When pulling away the truck shook and felt like a slipping clutch. On the highway I could not match my normal top speed with a few seconds of smooth running followed by a few seconds of rough. To shorten the story, I have found the front carb is running rich as the plugs for those two cylinders are covered in dry carbon. I have torn it down, cleaned it, checked the float levels and installed new idle mix needles.
I have found when setting the mixture on this carb, the engine is almost unresponsive to changes in the turns. In fact, it will run lean, even with the idle mixtures closed. So, my question is what to check next? At this point the performance is too bad to even get to 30 mph.

Thanks in advance, Buzz

To clarify what I have checked: Plugs and wires are new. Rick checked the SSI for me and its OK. New fuel and air filters. Valves have been set. I have done a compression check and got between 140 and 148 dry and between 145 and 150 wet.
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

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heinz
Austria
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Re: Number 1 Carb issue.

Post by heinz » Tue Feb 02, 2021 2:10 pm

Hi Buzz - If the spark plugs nr.1 + 2 are black it could be for many reasons. Spark plugs and the spark itself is sure o.k.?

If you suspect the carb, check the post "Whoa is me, truck running poor!" from "Pinzengauer" just two lines under your post.

As there are two cylinders working poor is the choke working correct? Maybe its running on choke?

The flaoter valve is working correct or staying open / leaking?

Are the carbs running synchronized?

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Buzz
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Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Tue Feb 02, 2021 7:49 pm

Hello Heinz and thanks for your post. I agree, its getting fuel from somewhere even with the mixture needles closed. I rebuilt these carbs about a year and a half ago. Perhaps I reassembled the choke incorrectly on number 1 although I would have thought the problem would have appeared before now. Still, worth checking. I will also recheck the float bowl levels and swap out the float valve while I'm at it.

By the way, yes the carbs have been synchronized at idle.

Thanks again, Buzz
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

User avatar
Buzz
United States of America
Posts: 229
Joined: Tue Dec 06, 2005 5:33 pm
Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Wed Feb 03, 2021 6:28 pm

Hello Heinz,
I went through each of the things that you suggested and it was the float valve. Specifically it was sticking both open and closed. Open enough to turn the plugs black at one turn. And then today when I went to measure the float levels the float balls were completely empty! So I just pulled out the float valve and put a new one in with the same two washers I always use. And now the truck is running perfectly.
Thanks for your time. I appreciate it. I have owned this truck for 19 years. And this is been one of the more perplexing problems I have had.
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

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

Re: Number 1 Carb issue.

Post by Tjerk » Thu Feb 04, 2021 1:34 am

Buzz wrote:
Wed Feb 03, 2021 6:28 pm
Hello Heinz,
I went through each of the things that you suggested and it was the float valve. Specifically it was sticking both open and closed.
So, what is the sticky goo in your fuel Buzz that causes the needles to stick?
Tjerk

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Buzz
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Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Thu Feb 04, 2021 6:49 pm

Tjerk,
I have concluded its not a sticky valve; but is instead, simple jealousy. See, I bought a G Wagon last spring with the idea that the G would become my Hunt Club and Beach truck. That would allow me the time to do some heavy maintenance on the Pinz. I Think the Pinz got jealous of me brining in a younger truck and decided to say "Lets start the maintenance right now"
Cousins2.jpg
Cousins2.jpg (693.31 KiB) Viewed 545 times
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

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heinz
Austria
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Joined: Mon Apr 02, 2018 3:14 am

Re: Number 1 Carb issue.

Post by heinz » Sat Feb 06, 2021 4:16 am

Hello Buzz!

Good to hear that you could locate the problen and solve it.

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Buzz
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Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Sun Feb 07, 2021 5:46 pm

Well, now I have a new twist for you. My announcement was shortly after a test run with the intake manifold and air cleaner off. When I put the truck completely back together she fell on her face as soon as you pushed the accelerator with any real authority. So, I decided to start form zero with a recheck of the the ignition, valves and carburetors.

While in the process of reassembling number 1 carb I found a part missing. See the pic below. Carb 1 on the left. Carb 2 on the right.
TwoCarbsresized.jpg
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That's a 10mm hole in the side near the accelerator pump! That side is away from you when you are fiddling with the mixture screws and the idle. I do not know when or how this plug came out. I have to assume this is my main culprit in the trouble I have been having. I will not know or say more until I have the hole plugged and truck up for testing tomorrow or the next day.

Have any of you seen this issue before? - Buzz
Attachments
Carb2Resized.jpg
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"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

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heinz
Austria
Posts: 17
Joined: Mon Apr 02, 2018 3:14 am

Re: Number 1 Carb issue.

Post by heinz » Mon Feb 08, 2021 2:23 pm

Hi Buzz!
I think that this may be the hole you are talking about. This is the air hole for the starting device. I practically don´t know if it´s affecting the function of the carb, but it definitely shold be closed to the outside.
I have added a few pics for explanation as "pdf" files, as they are smaller in size, compared to the jpeg - I hope it works.
If iot does not work with the pdf format I can send it as jpeg.

Rgds,
Heinz.
Pinz Carb 04089x.pdf
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Pinz Carb 04088x.pdf
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Pinz Carb 04087x.pdf
(124.27 KiB) Downloaded 20 times
Pinz Carb 04086x.pdf
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Pinz Carb 04090x.pdf
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heinz
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Re: Number 1 Carb issue.

Post by heinz » Mon Feb 08, 2021 2:30 pm

To few the pics on the post above you may have to click on it and than a file will appear on the left side of the bottom line on your PC. Let me know, if you could not see the pics.

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Buzz
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Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Tue Feb 09, 2021 12:00 am

Got your pictures as PDFs and was able to open them by downloading and opening with Adobe. And yes, you are correct, that is the opening and I think it where the super rich condition was coming from. I think the vacuum was acting with the hole and was pulling fuel up to flood everything. All was well at idle and low revs. Then when I stepped on the gas the fuel was pulled through without any regulation by the jets. I have replaced the plug and will post pictures of the repair tomorrow. I am up past my bedtime; but, optimistic about a resolution.

Thanks, for your response. - Buzz
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

User avatar
Buzz
United States of America
Posts: 229
Joined: Tue Dec 06, 2005 5:33 pm
Location: Jacksonville, Fl.

Re: Number 1 Carb issue.

Post by Buzz » Wed Feb 10, 2021 7:54 pm

Ok, I replaced the plug on carb 1 the other night and am happy to report that the truck is running like a champ. Maybe, better than ever. I think that plug had been leaking a long time and it may be something others may want to check on their own trucks.

As posted earlier here is what I found as I cleaning the carbs in pursuit of the gremlins that had been eluding me for weeks. The hole where the plug fell out is marked with the yellow arrow.
Fix1a.jpg
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This plug is not shown as a "part" in any Zenith parts manual I have been able to find. Looking closely you will see the plug was made slightly concave and then "dimpled" with punch or press to expand the plug in the hole. Then it was staked to further prevent the plug coming loose. I have marked one of the impressions meant to retain the plug.
Fix1bjpg.jpg
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So, to make my own plug, I used some thin aluminum scrap I had on hand to cut out a square blank. The hole itself is stepped with small ledge running around the circumference of the inner edge of the hole. The ledge is 1 mm deep and 1 mm wide. I found that a 7 mm socket fit in the hole and against the step very well. So I used the socket to make a pattern.

I then used some heavy scissors and files to progressively fit the blank until it was about 2 mm too large.

Then placed the blank over a hole in my vice to put a dimple into it with a punch. If were doing it over again I would probably just use washer as the support to punch the dimple.

Next, I took the dimpled blank (plug) and placed in the hole convex side up and seated it in place with first the 7 mm socket as a punch and then gentle tap with a flat faced punch to expand the plug in the hole.
Fix7.jpg
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Last step, as insurance, I covered the plug with JB Weld TankWeld
Fix8.jpg
Fix8.jpg (48.05 KiB) Viewed 415 times
I will probably go ahead and put JB Weld on the second carb also. The elimination of the leak gives a startling improvement in performance and I sure do not want a second plug to fall out. Especially, if I were off road somewhere.

Thanks to Heinz for offering suggestions while we solved this puzzle. - Buzz
"It's as stupid and wonderful as owning a pet elephant."
1974 Pinzgauer 710M
1990 Puch G Wagon 230 GE

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heinz
Austria
Posts: 17
Joined: Mon Apr 02, 2018 3:14 am

Re: Number 1 Carb issue.

Post by heinz » Thu Feb 11, 2021 1:30 pm

Very nice to hear that you ´ve got the problem solved and the engine is running smooth as it should - with a smooth running engine the Pinz is very nice to drive.

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