I purchase a 446-80 paired with what appears to be a k46 deck. The correct belt for this unit should be a C23359, When installed the belt is out of alignment with the deck drive pulley and will jump off when drive is rotated by hand, plus the idler pulleys are also out of alignment with the clutch pulley.
A74 belts measures 5 inches longer than the EOM C23359 belts but puts all of the pulleys in proper alignment.
I am scratching my head on this one. Is there a difference in the length of the Mule drive for a long and short frame tractor. I have 3 decks and mules but have not found a difference in any of them.
If the weather is nice tomorrow, a deck will be installed and photos taken.
5" in belt length is a huge difference. A K46 is exactly the right vintage deck for a 1980 tractor and all mule drives are dimensionally the same. There are some differences but nothing to prevent them from interchanging between long and short wheelbase tractors. Hopefully your pictures will help determine the problem.
This is the deck I have been running with the A74 belt and it should probably be an A73. This picture is with the C23359 belt installed. Notice how it rubs on the mule brace.
This morning I changed the deck but not the mule. This is with the C23359 installed and it is only slightly better.
Here is a shot of the second deck and another mule. This time there is a noticeable change in belt tension.
Both decks have had the mule mounting brackets rewelded and the first mule appears to have a slightly different adjustment arc on the idler mounts. Possibly the previous owner modified all of the wear points and there is a stacked creep on the overall dimensions. I have not been able to find any single dimension that is different by more that a 1/2 inch between the 2 decks. The second deck has aluminium spindles making it a later model deck.
The second deck needs all the spindle bearings replaced. I want this tractor to be the trim mower where there is a chance of hitting a rock. Rocks are just to ruff on the RM60.
Only guessing here, but the pulley on the left side, sitting on the seat, in the first two pictures looks smaller than the third picture. And it looks like the arm, third picture, where the pulley is bolted to seems to have a more of a downward slope than the in first two pictures. Some thing is different.
Here's some pics, I had to put a new c23359 on this morning. I had been running the L471 belt that came on the 448 to it's end. This morning it kept turning over so it is done.
deck's on, blades sharp, let's go it's time to mow
propane1 wrote: ↑Sat May 11, 2024 4:43 pm
Only guessing here, but the pulley on the left side, sitting on the seat, in the first two pictures looks smaller than the third picture. And it looks like the arm, third picture, where the pulley is bolted to seems to have a more of a downward slope than the in first two pictures. Some thing is different.
Noel
You have a good eye Noel. I would have never seen that. Harry
@propane1 Noel, You are correct about the angle of the idler mounts being at a different angle. That is a difference in the 2 mules. The photo that @Timj posted looks like the same version of build that may last 2 pictures show. As Bob said the mules should be interchangeable, but will have a slightly different profile.
The belts used by Case a Colt at between and A and B belt profile. Idlers and pulleys purchased after market are all so A and B profile. If and A profile pulley is used the pulley diameter can be the same as Case but the belt will not nest as deep. If the drive hub and idlers are aftermarket "A" then there could easily be several inches of added travel needed. 1/2" increase on the drive pulley diameter would add approximately 1" and the a 1/2" change on each idler would add about 1".
Since one of my decks had hangers reattached by previous owner, and there is a noticeable belt length change on it, the hangers measure a closer to the front of the deck. What I haven't confirmed is the centerline distance from the drive spindle to the hanger ears centerline.
Bob is sending me an eom drive pulley and it should be delivered Monday.
Stay tuned. In the meantime the when the 446 was purchase it was impossible to start without removing the air cleaner and priming. There is no evidence that it ever had a fuel pump. I plan on putting a 1-2 PSI electric pump on it this week.
@propane1 Noel, You are correct about the angle of the idler mounts being at a different angle. That is a difference in the 2 mules. The photo that @Timj posted looks like the same version of build that may last 2 pictures show. As Bob said the mules should be interchangeable, but will have a slightly different profile.[/b
The mule drive bracket and pulleys should all be the same, any differences are at the rear of the mounting frame. Sorry for any confusion. I definitely think that there is an issue with the one that came with the 1980 tractor.
deck's on, blades sharp, let's go it's time to mow 
I would have never seen that. 
Harry