New Member trying to get 3 712's running better

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EdBolz
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New Member trying to get 3 712's running better

Post by EdBolz » Wed Jun 28, 2017 8:37 am

I'm not sure how I got here, but I'm now knee deep in it. 3 Pinz 712's being used by a zip line company to bring customers up the mountain. 1 runs fine, one wouldn't idle properly, and one had a blown spark plug and carb issue (M6 screws holding the lower to the upper stripped, which I've read is common). Put an insert for the spark plug - that's good. PUlled the one carb wiht the stripped screws - I saw a post somewhere that the screws are M6x1.0mm pitch (coarse), but I measured them to be 0.75mm pitch (fine), for which I could NOT find a helicoil, so I tapped it 1/4-20. Seems ok. That one seems to run ok now. I rebuilt both carbs on one that they reported wouldn't idle properly, and it's no better. Having a problem with the chokes on that one not turning fully off - the return spring was missing, replaced that, but it still won't return to fully off. But, not sure if I screwed up the choke plate position - it's annoying that the shaft is square on the lever side - allows you to put it back together in 4 diff positions. I could see a dark section on the plate that seemed to coincide with the large opening in the carb - put them both back in that way. It seems the choke is ok from a function standpoint becasue it will start with the choke fully on - seems to act normal. AS it warms up, closing off the choke raises rpms a bit, but shuts right down when the choke is turned down past halfway. So I have many questions - I've seen a lot of water collecting on the choke side of the carb when running. It's def water, not gas. Both carbs. Condensation? I need to check timing, but don't know where the marks are. The fuel filter, which is loaded with junk, is plumbed between the tank and pump, which puts it in the low pressure side, which I think is wrong - there could be a coarse filter there, with very little restriction, but the fine filter needs to be on the high pressure side to prevent sucking air, right? Are the main jets adjustable? They were loose when I took them apart - now they are tight (they were tight on one of the others). I've read the posts on syncing the carbs - nice posts - I have the syncometer. Need to get this one running as they go full time starting this weekend and need all three running well! Thanks for any help.
Ed

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John L
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Location: Covington, Louisiana

Re: New Member trying to get 3 712's running better

Post by John L » Wed Jun 28, 2017 2:20 pm

From your post there are a lot of pieces of information the guys may need to help you diagnose your trouble. I am not the engine expert like some of these guys. But, I have had a couple of issues I've run down with similar symptoms. I'll just comment on the fuel filter as this could easily be your problem. The filter is supposed to be located between the tank and the pump on the intake side. You reference low pressure side; but I'm assuming you have the original mechanical pump and not some electric fuel pump. If it is standard equipment then change the filter. Any restriction in your fuel line could easily explain why it runs with the choke on and shuts down when it's closed. It's an easy change. Also check the fuel lines from tank to carbs and make sure they aren't spongy. When they get spongy they close down as rpms increase and the carbs get starved for fuel and quit. Try the easy fixes first then work towards the more complicated as you go. Just my two cents. It would be nice if the filter solves your problem

One other thing, you mentioned the filter is full of crap. Make sure it isn't flakes from the inside of your fuel tank. Sometimes these tanks start peeling and paint chips get sucked into the filter and clog it up. If this is happening there is a series of posts on the red flakes of death and how to solve them. Good luck. I'm sure some of the other guys with more technical knowledge can assist on the other issues if the filter doesn't solve the problem.

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John L
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Re: New Member trying to get 3 712's running better

Post by John L » Wed Jun 28, 2017 2:23 pm

Ed... one other thing. The flywheel has an orange v or mark at TDC. So, if you're trying to confirm that the timing is right look for the orange mark. You can turn it with a large socket. If memory is correct, which generally it fails me, it's a 25mm socket. Good luck.

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pcolette
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Re: New Member trying to get 3 712's running better

Post by pcolette » Wed Jun 28, 2017 2:36 pm

Here is a photo of the pointer and pulley for checking the timing. There is a small groove cut in the pulley and when the pointer is on it, the engine is at TDC.
IMG_3109.jpg
IMG_3109.jpg (234.27 KiB) Viewed 819 times
A suggestion on the fuel lines: when replacing them do your best to find the metric lines, 5mm and 7mm. SAE fuel line never seems to seal properly and ends up sucking air.
Paul C.
_________
'73 Swiss 710M
'72 Swiss 710M (For Sale)
'89 Puch 230GE
2002 MB G500 (For Sale)

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edzz
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Re: New Member trying to get 3 712's running better

Post by edzz » Wed Jun 28, 2017 9:27 pm

Please list your location in your profile. You may find a member that is local to you that could help get you up to speed on these trucks.
Ed
75 710K (sold)
06 2WD Ural Patrol (sold)
69 2WD Rokon Trailbreaker 4 sale
A few Honda Trail 90's (all sold)

Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

EdBolz
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Re: New Member trying to get 3 712's running better

Post by EdBolz » Thu Jun 29, 2017 9:57 am

Thanks so much for the helpful responses, Ed & John.
So the filter is in the right spot. OK. Any ideas on where to purchase replacement filters?
Fuel lines do NOT look good - and I was surprised to see no clamps on the carb fittings - I guess its a low pressure system.
Hoping it's not the 'red flakes of death' - I don't know why, but that sounds bad.
Any thoughts on the condensation on the choke side of the carbs? That's bothering me.
Today I need to go in there to replace the distributor seal on the one that doesn't idle - oil everywhere - so then I'll need to do the timing - thanks for the picture, very helpful (I would have been looking on the back side of the motor!)
Great forum. Location is Lake George, NY.

EdBolz
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Re: New Member trying to get 3 712's running better

Post by EdBolz » Thu Jun 29, 2017 10:02 am

Another stupid question - how do you verify the choke plates are properly aligned? As I mentioned before, the stud is square, which allows the plates to be installed in 4 diff positions - doesn't seem ideal.

undysworld
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Re: New Member trying to get 3 712's running better

Post by undysworld » Thu Jun 29, 2017 11:07 am

Here's a link to common parts cross-reference, courtesy of SWP and Goatwerks: http://www.goatwerks.com/interchangelist.htm
I usually get filters at NAPA, and I get the clear ones so you can watch for contaminants to some degree.
Replace all the old fuel lines, just to be safe. I don't recall the psi, but yeah it's low.
Don't worry prematurely about the red flakes. Not everyone has the problem, and worrying won't influence your luck.
I don't know the answer to the choke offhand. The choke plates are shown on pg 1.9 in the parts manual, and that probably indicates the position. But it shows 2 versions. Can you show a pic or describe the plate? One appears to have several small round holes, while the second seems to have a larger oblong hole plus other round ones. Sorry, but I have no way of adding the photo.
If you do not yet own the parts and repair manuals, you really will be needing them eventually, imho.

EDIT: Here is a photo: http://www.pinzgauer.com/parts.php?cat= ... view=01-40

2nd EDIT: Oh. Duh. Check the choke plate position on a carb on the truck that is working properly.
Last edited by undysworld on Thu Jun 29, 2017 11:26 am, edited 1 time in total.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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audiocontr
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Re: New Member trying to get 3 712's running better

Post by audiocontr » Thu Jun 29, 2017 11:10 am

As long as the plate doesnt leak fuel, youre fine
1973 712m
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EdBolz
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Re: New Member trying to get 3 712's running better

Post by EdBolz » Fri Jun 30, 2017 6:47 am

Thanks Undysworld.
Replaced the filter yesterday - the cross ref number on the list is a steel body version, but Napa had the clear version. The one in place had dual nipples on each end - 5mm and 7mm, which is better. It was diff to get the 5mm hose on the 7mm nipple on the discharge end, but it seems ok. Red flakes in the new filter almost immediately. NO change to performance.
The choke plate has a series of holes only - no slots. I did use the orientation of one of the other chokes as a guide, but I don't know/trust the history of these, so I think the repair manuals would be a good idea. I'm about 90% certain that the chokes are right, but would love to verify.
Yesterday I tried to check the timing, but my 25 yr old timing light didn't work (haven't used it in 20 years prob) - is there any special requirement? Ordered a new light - it will be in this morning. And after checking the timing, I'm out of ideas, except to open up the butterflies more. Closing the chokes just kills it - even though it seems normal while under choke conditions, although very rich. I can't think of any other clues that could be helpful.
BTW, this is for a zip line company - Eagle FLyer, in Lake George, NY, and they are looking for an experienced Pinz mechanic to help them out on a regular basis - if anyone is or knows of anyone interested........ I'm not a mechanic, just mechanic-al.
After installing the filter, it didn't fill with gas - just a trickle coming in with no level. I pulled it and blew into the tank to clear any chunks, which seemed to help, but no real improvement in performance.
Again - thanks for all the help.

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pcolette
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Re: New Member trying to get 3 712's running better

Post by pcolette » Fri Jun 30, 2017 7:18 am

There is a drain plug on the bottom of the gas tank and it may not be a bad idea to completely drain the tank and get rid of as much of the accumulated junk that you can. It likely won't all come out but may help. To completely clean it out requires dropping the tank, not that hard a job but easier with a helper.

You'll need a 12V battery for your timing light. I use a spare that I keep around the shop and set it on the ground by the passenger door.
Paul C.
_________
'73 Swiss 710M
'72 Swiss 710M (For Sale)
'89 Puch 230GE
2002 MB G500 (For Sale)

undysworld
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Re: New Member trying to get 3 712's running better

Post by undysworld » Fri Jun 30, 2017 8:47 am

I'd agree with Paul C that you probably want to drain that tank which has the red stuff in it. The tank should be cleaned and relined, I'd guess. To avoid the problem when diagnosing things, rig up another temporary tank to use for now. I use an old tank I pulled from a junk mower.

Seems to me that the inductive pickup on a timing light won't work with the stock military shielded wires. I made up a non-shielded wire to trigger the light.

There are lots of us here that aren't really mechanics either. (Sometimes we only know enough to be dangerous. :twisted: ) If you can find a good VW (old aircooled) mechanic around, you might find that he/she will find your Pinz engine fascinating and a huge help in sorting things out. I've found PInzgauers to be pretty common-sense things to work on.

If the carbs continue to give you grief, lots of guys have reported excellent results from shipping the carbs to Jim LaGuardia (Goatwerks) to be rebuilt and pre-tuned.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
I hope to die in my ski boots... ...just not today. Me

EdBolz
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Re: New Member trying to get 3 712's running better

Post by EdBolz » Fri Jun 30, 2017 12:54 pm

Thanks for all the help. You're going to be pissed when you learn what the culprit was. It was a fuse. The cutoff solenoids weren't opening. I had pulled the wires from them a while ago and noticed no difference, but wasn't sure what they did. Now I know, and one of the Managers, Steve, who was driving it at the time the fuse blew, can now pinpoint exactly when and where. I spent many hours working around that - but a call to Swiss Army Trucks lead to the solution. Oh well, live and learn. Thanks again for the help.

undysworld
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Re: New Member trying to get 3 712's running better

Post by undysworld » Fri Jun 30, 2017 7:51 pm

I believe I already said "Duh". :D Shoulda thought of that.

The solenoids are a really simple check: key on - pull the connector on the solenoids one at a time and listen for that click.

For that matter, any time you have an electrical problem of any sort, it's not going to hurt you to push all the breakers prophylactically. I've found some of the circuits to be somewhat counterintuitive if you're used to American cars. I think the schematic is in the electrical section as a sticky. (?)

Glad to hear it was so easy.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
I hope to die in my ski boots... ...just not today. Me

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edzz
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Re: New Member trying to get 3 712's running better

Post by edzz » Sat Jul 01, 2017 11:17 am

EdBolz wrote:Thanks for all the help. You're going to be pissed when you learn what the culprit was. It was a fuse. The cutoff solenoids weren't opening. I had pulled the wires from them a while ago and noticed no difference, but wasn't sure what they did. Now I know, and one of the Managers, Steve, who was driving it at the time the fuse blew, can now pinpoint exactly when and where. I spent many hours working around that - but a call to Swiss Army Trucks lead to the solution. Oh well, live and learn. Thanks again for the help.
Happy it worked out and Thank You for posting the cure.

For future reference if this truck has fuses and not breakers the nice color schematic will not be 100% correct. The Swiss pattern trucks have breakers while others commonly have fuses.
Ed
75 710K (sold)
06 2WD Ural Patrol (sold)
69 2WD Rokon Trailbreaker 4 sale
A few Honda Trail 90's (all sold)

Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

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