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Bird76Mojo

My ongoing Allis 720 saga thread

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Bird76Mojo

This thread will be to document my ongoing laundry list of problems with my Allis 720

Just when I thought I had her going, running well, and everything operating correctly with the hydro, I drove it over to dad's house to see what he was doing with the combine and I made the mistake of shutting it off, and it wouldn't restart! UGH!! It tries to start, as in it spits and sputters.. It has spark according to my spark tester that you touch to the plug wire.. I checked both plugs and although they're a little sooty, they don't look that bad. I'll pick up some new plugs tomorrow after work just to be sure.

I loosened the fuel hose and it started leaking fuel out, but I plan to totally remove the fuel hose and see if it's getting good flow or not. Next will be to remove the carb again and see if anything is suspicious in there...

I suspect timing, but I'm unsure right now.. It did start a little harder than normal when I first fired it up after work today, but after it started, it ran fine all the way to dad's house and idled well once I got there..

I swear. this tractor has gremlins like nothing I've ever owned!


List of things I've done so far to get her ready to work and look better doing it:

  • Tubed one rear flotation tire..
  • Rebuilt one rear dropbox completely with all new bearings and seals, handmade gasket..
  • Installed a new top/inside bearing in the other dropbox..
  • Installed new vent valves in box dropboxes..
  • Sandblasted both dropboxes and painted them with etching primer and Rustoleum black industrial enamel..
  • Sandblasted, greased, and went through ALL of the rear brake parts, and installed new disc brake actuator springs (John Deere carries them cheap, or Ebay)
  • New seals installed in the plates behind the rear brakes..
  • Removed and cleaned the carb once already..
  • Cleaned the fuel tank thoroughly and installed the electric fuel pump, filter, shutoff valve, and new rubber fuel hose..
  • Used heavy rubbing compound, then cleaner wax, on all of the original paint on rear fenders, sides of chassis, hood, pto cover, etc..
  • Sandblasted and repainted all tins around the hydro cooler, trans top cover, control lever cover tins, etc..
  • Fresh hydro filter, with new fluid last year or so..
  • Installed one of my spare rear pto shafts and clutches..
  • Sandblasted and painted the floorboards with bedliner..
  • Went through the 3pt hitch and painted it last year..
  • New hoses on the rear lift cylinder..
  • Installed some good used front hydraulic couplers since the originals were lightly damaged..
  • Cleaned and painted the battery tray area, and hold-down bracket..
  • Installed a bushing today in the hydro control lever in the tunnel, that I robbed from my parts tractor..
  • Sandblasted and painted the belly pan with my favorite Rustoleum red oxide primer and topcoated it with Rustoleum black industrial enamel..
  • Adjusted the drive belt tensioning system to factory specs (previous owner had it all messed up!)
  • Installed a new ignition switch and wiring plug due to the factory unit being full of rusty terminals.. (Ebay has the plug cheap!)
  • Greased all zerks I could find..



The saga continues.......



 

Edited by Bird76Mojo
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Talntedmrgreen

The two things that plague me most with these Onans

-fuel in the oil (usually remedied by a 12v pump or a fuel valve)

-fouled plugs (I go through 2 or 3 sets per year, per tractor)

 

Check the oil and then put plugs in regardless of spark. 

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Bird76Mojo

Thanks for the advice Mr. Green. It's much appreciated. I'm almost at my wits end with this tractor. I was nearly ready to push it downhill in to the pond today when it did this. Luckily my father's cool head prevailed this time.

I plan to get new plugs after work tomorrow and will report back with any changes..

A Kohler carb conversion may also be in the cards soon...

I do have a shutoff valve after the 12v fuel pump, just for peace of mind.

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Bill725

I thought a conversation with @ShaunE, he stated there are (2) different main jet settings. One from Onan and another from Simplicity. And I thought he said the one from Simplicity is the one which works, Hopefully he will respond.

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Talntedmrgreen

Gerald, were you having running issues prior to this ruogh start problem?  Carbs don't change jet settings on their own, but can become obstructed by debris.  I have had a few machiens that were out of time, or needed the points adjusted, but those are simple tasks and I have not had any change on me later.

Plugs are a lot easier to try, and I only share this becuase I have had to change them so, so many times.  I cannot find the key to keeping the plugs clean.  Just this past Friday I fired up my Twin 20's, and both started easy and ran good.  The better runner of the two always eats plugs, and after parking it for a few hours, I tried everything to get it going again.  Nothin.  I tried so long the battery ran down.  I actually gave in and decided to leave it out for the night, and tow it in Saturday.  Just about ready for bed, later on, it hit me....I never tried new plugs.  I put my PJ's on, tried one more time with no luck, swapped plugs and it fired right up.  I have been able to clean my fouled plugs and save them for later, and that works well. 

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Bird76Mojo

I attacked it first thing after work and got down to the issue. First I tried installing new plugs with no change at all. But I'm still glad I picked them up. Gapped them to .025"

Then I checked for full fuel flow, and it was very good.

So I removed the engine tin piece to inspect the points, then the points box cover. Turns out the top screw that holds the points had worked itself completely loose! I've never personally been in the points box since I bought the tractor, so it was a good learning experience for me. There was hardly any oil in the points box as well, so that's a good sign. Maybe a little from vapor.. So I gapped the points to .020" and she fired up better than ever. Ran smooth as silk after a small adjustment of the air screw on top of the carb. (I had fiddled with it the other day when it wouldn't start up again)

With no time to waste I then dug out my bracket to mount the front plow. Slathered some anti-seize on some appropriate bolts, and mounted it up. Picked up the heavy chonker of a plow and dropped it on my landscape wagon to transport it to the tractor..


Another question for you guys though. Does your hydro fluid get milky looking or frothy? The hydraulics seem a little loud to me, and the fluid gets pretty aerated in my opinion. I still think I'm going to treat her to a fluid and filter change once again, just to be sure. What fluid are you all using, and what does it look like after running for 30 minutes or so when you check it immediately?

Here's the fruits of my labor so far..


 

20200916_192113.jpg

Edited by Bird76Mojo
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Bill725

 

11 hours ago, Bird76Mojo said:

What fluid are you all using,

You may want to consider Amsoil Synthetic Tractor Hydraulic - Transmission Oil All Weather SAE 5W-30. I have it both of my Sovereign Sundstrands.

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Bird76Mojo
10 hours ago, Bill725 said:

 

You may want to consider Amsoil Synthetic Tractor Hydraulic - Transmission Oil All Weather SAE 5W-30. I have it both of my Sovereign Sundstrands.

Although I believe in Amsoil products, I won't pay their premium prices for it. At least not in my older used equipment. In my race truck, maybe..

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Bird76Mojo

After work yesterday I picked up some Harvest King (Rural King brand) Dex/Merc in a 2 gallon jug for $19.99, and a WIX filter. Today, I set out to do a fluid change after fixing a friends car for her..

I removed the sending unit and the suction elbow to drain as much nastiness as possible. I used a little of the Dex/Merc to help push the old fluid out of the drains as well. Reinstalled the suction tube and sending unit with some high-temp sealant, and swapped the filter.. Once filled, I removed the setscrew on the pump, unhooked the plug wires, and tried my best to prime the pump. It seemed like air would never really stop coming out, but it's one of those things where it's hard to tell when you're finished. So after several times, gushing fluid everywhere, I put some high-temp thread sealant on the setscrew and snugged it down. Sprayed everything on top and underneath with some brake cleaner, and reinstalled the freshly painted belly pan.

I also learned my battery is showing it's age while priming the pump, so I had to hook up the charger...

I started her up and was AMAZED at how quiet the hydraulics were!! A night and day difference! Also, they were 10 times faster than before. I was amped up to play in the sandbox after that. lol

I backed up to the rear blade and got it hooked up, and started pushing brush in the woods, trying to clear out the undergrowth to pretty the place up a little. The tractor showed it's lack of weight/traction quickly, but I kept playing for about an hour anyway. Too much fun! :) 

So the next task is to reinstall my double set of rear wheel weights.

I made some foam pieces last week by cutting/trimming some closed cell foam and then hanging it up to give it several coats of Plasti-Dip. So I installed those today before reinstalling the seat. They're just an attempt to shed any water off to the front or rear instead of it going in to the brake system. The way I see it is they're better than nothing at all..

20200919_144358.thumb.jpg.f9babe4ce13754aa9494bc51ab448b6e.jpg
20200919_144411.thumb.jpg.a13c7cecb49cd5184e4a3ac18a29c27f.jpg



Again, here are the fruits of my labor.... Not bad for a $500 tractor!!

Hopefully I can get started on the Allis 616 next spring and I'll add it to this thread. I have two new Onan shortblocks and one is going in the 616.. It will become my full time mowing tractor to replace my tired old Simplicity 7119 that's been repowered at least 3 times.


20200919_180903.thumb.jpg.c375711421c23ab871d70affe2e114e8.jpg
20200919_180817.thumb.jpg.d72b57fde7a8891536e959136366fdf7.jpg

Edited by Bird76Mojo
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Bird76Mojo

Thanks guys. It's a fun little unit to operate. Now, if only I could find a bushhog for it.

Anyhow, at least I'm ready for winter this year WAY before it's actually here. lol

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Bird76Mojo

This tractor is a mini-bulldozer with the front and rear blade!! With some patience, it will clear a surprising amount of wooded area. I got the double set of rear weights mounted yesterday, and today after work I started clearing the scrub (poison ivy/briars/honeysuckle/small saplings) in my wooded backyard.

I WAS AMAZED at how well it did if you just take your time and use good sense.. Pics to come this weekend as I get more cleared. :)

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Bird76Mojo

I did some more clearing today after work. I worked on it yesterday for about 2 hours, and today for about 3-4 hours. The 720 performed VERY WELL! I'm still amazed at what this little tractor can move. Dad was also very surprised and he's been a farmer and heavy equipment operator his whole life.

20200925_145954.thumb.jpg.8b78226e0efabd0b6dc445dbe8267658.jpg

I made a short video just to show my progress to my family members, and it doesn't show any tractor work, but if anyone would like to see my progress then feel free to check it out. It's listed as invite only on Youtube.

Boring video: 




GB :)


 

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