19738hp4spd 0 #1 Posted April 20, 2019 Hello Everyone, I’m new to this site and the Wheel Horse addiction. I recently pick up a 1973 8hp 4 spd from the original owner with all the original manuals and such. The thing runs like a dream and is beautiful shape. When I test drove it drove fine. But now the clutch is not disengaging when I’m trying to shift the machine I tried to adjust the peddle and that didn’t work. As I’ve read on this site that it wouldn’t work. I’ve also gained some knowledge on how the “clutch” works with the idler pulley and belt guard to produce slack on the belt. The only thing I can see that doesn’t match the owners manual is that the belt guard is missing the bottom adjustment tab by the pto pulley. The top of the belt “the flat side” is showing excessive wear from the few days I’ve ran it. When I got the machine the belt looked new and is the correct size. I have a new belt I’m picking up tomorrow just to be sure but I don’t want to put it on and smoke it up when the under lying issue still remains. Share this post Link to post Share on other sites
daveoman1966 3,762 #2 Posted April 20, 2019 The Wheelhorese OEM belt is # 7473 for that 1973 tractor...8hp 4sp. Belt is 82" long x 5/8" width. If you use an aftermarket belt, that MAY be the whole problem. Aftermarket belts are not geometrically identical to OEM nor...IMHO....are they of the same quality. You have the right Idler pulley and return spring in place...working correctly? 2 Share this post Link to post Share on other sites
Ed Kennell 38,669 #3 Posted April 20, 2019 Like Dave states above, make sure the idler pulley is free and working properly. I have found the roll pin that locks the clutch lever (6-28) to the cross shaft sheared in several tractors. If this pin is sheared off, the idler pulley will not engage and disengage properly. Scribe a line across the lever and end of the shaft to determine if the lever is slipping on the shaft. 3 1 Share this post Link to post Share on other sites
squonk 41,343 #4 Posted April 20, 2019 I think you have a damage belt guard or possibly the wrong guard on it. Pics would be helpful. I use aftermarket belts on all my tractors both gear and hydro's and never an issue. 2 Share this post Link to post Share on other sites
19738hp4spd 0 #5 Posted April 20, 2019 8 hours ago, daveoman1966 said: The Wheelhorese OEM belt is # 7473 for that 1973 tractor...8hp 4sp. Belt is 82" long x 5/8" width. If you use an aftermarket belt, that MAY be the whole problem. Aftermarket belts are not geometrically identical to OEM nor...IMHO....are they of the same quality. You have the right Idler pulley and return spring in place...working correctly? Thanks I looked up the pulley and it seems to be the right size just by taking rough measurements. But I’m not sure about the rerun spring. Or how I can check that. Share this post Link to post Share on other sites
rmaynard 15,608 #6 Posted April 20, 2019 Another thing. Shifting is only done with the tractor fully stopped and clutch depressed. There is no shifting "on the fly". This transmission does not have syncronizers. 1 Share this post Link to post Share on other sites
953 nut 55,787 #7 Posted April 20, 2019 13 hours ago, 19738hp4spd said: I have a new belt I’m picking up tomorrow just to be sure Be sure to get a fabric wrapped belt. I have had good results with the "Kevlar" belts from Tractor Supply. 3 Share this post Link to post Share on other sites
Ed Kennell 38,669 #8 Posted April 20, 2019 I never had a problem with TSC belts. And when the length is a question, I buy three different lengths and return the two that didn't fit. Just keep the belts and the sleeve clean. 1 Share this post Link to post Share on other sites
pfrederi 17,881 #9 Posted April 20, 2019 You need that bottom tab to be able to shift. If you can't weld the tab back on the bottom of the guard you could easily make a wire guide. WH used them on several models. These pics should give you an idea of what you need to make 3 Share this post Link to post Share on other sites
19738hp4spd 0 #10 Posted April 20, 2019 1 hour ago, pfrederi said: You need that bottom tab to be able to shift. If you can't weld the tab back on the bottom of the guard you could easily make a wire guide. WH used them on several models. These pics should give you an idea of what you need to make Thanks that’s super helpful. There isn’t a bottom tab and it doesn’t look like there was ever one but I can definitely rig something up with some wire. I’ll send some pick tomorrow. Share this post Link to post Share on other sites
19738hp4spd 0 #11 Posted April 20, 2019 What function does that bottom tab play in providing slack on the belt ? Share this post Link to post Share on other sites
Ed Kennell 38,669 #12 Posted April 20, 2019 It helps support the weight of the loose belt and if adjusted correctly will prevent the belt from making contact with the engine drive pulley. The bottom flange on the belt guard also serves this function. 2 Share this post Link to post Share on other sites
19738hp4spd 0 #13 Posted April 20, 2019 Thanks I’m going to try and fab one up I just wanted to know the function so I can ensure it preforms it. Share this post Link to post Share on other sites
Ed Kennell 38,669 #14 Posted April 20, 2019 We are assuming the idler/tensioner pulley is fully disengaging the belt and allowing it to go slack. If the belt is not loose, the belt guard and the support wire will not keep it from contacting the engine pulley and the belt will keep rotating. 1 Share this post Link to post Share on other sites
The Tuul Crib 7,337 #15 Posted April 21, 2019 On 4/20/2019 at 6:46 AM, Ed Kennell said: Like Dave states above, make sure the idler pulley is free and working properly. I have found the roll pin that locks the clutch lever (6-28) to the cross shaft sheared in several tractors. If this pin is sheared off, the idler pulley will not engage and disengage properly. Scribe a line across the lever and end of the shaft to determine if the lever is slipping on the shaft. Share this post Link to post Share on other sites
19738hp4spd 0 #16 Posted April 28, 2019 Thanks for everyones input I have an update to my problem. I finally got a chance to get back to horse today. It fired right up like normal and the thing went right into gear and mowed the entire yard no issues. I fabricated the the bottom belt guide but didn’t have to put it on. The top of the drive belt is still pretty chewed up no clue why. but I’m going to wait to install the new one. 1 Share this post Link to post Share on other sites
19738hp4spd 0 #17 Posted May 8, 2019 So the second mower with the new horse got about 30mins in and the dang belt wouldn’t disengage again. I turned the machine off and then back on and it worked. Thanks again for everyones help. Everything looks good that I can see the idler pulley is free all the pins are good (6-38) I found a new belt guard on eBay that is coming in on Friday maybe that will help. And picked up a few different size belts. Would the spring 6-32 affect this function? A real rookie question when I read the owners manual I interpreted that the drive belt goes on top of the tab on the belt guard that is forward of the idler pulley is that correct? Share this post Link to post Share on other sites
ET160 29 #19 Posted May 9, 2019 I am having a similar problem with my B80. I have experimented with a variety of belts. I think part of the problem may be that new belts are actually often 21/32" or wider, not 5/8" and do not fit down into the pulley completely. Share this post Link to post Share on other sites
19738hp4spd 0 #20 Posted May 9, 2019 Did you have any luck with a larger belt? Share this post Link to post Share on other sites
ET160 29 #21 Posted May 9, 2019 I've gone through several. The Toro 7473 that is supposed to be right for the B80, grinds. The best so far has been a NAPA B80; that disengages, but is jerky upon release. I have ordered a bunch of different NOS belts to try on ebay. I am running my 40 year old original belt now, which is ragged but still works. Share this post Link to post Share on other sites
19738hp4spd 0 #22 Posted May 9, 2019 Original nice. Mine was newish when I got it and it’s messed up so so I’m thinking I have something stupid wrong which is why I asked about the belt guard belt configuration. Share this post Link to post Share on other sites
ET160 29 #23 Posted May 11, 2019 I tried three more belts today, with one working pretty well. It disengages fine, but is a little jerky coming off. It's acceptable. The belt that works is 82.5" long and 5/8 wide, meant for a Scag mower. From what I have observed, width is critical. The belt that work okay is a little narrower than the others and sits lower in the pulley. Share this post Link to post Share on other sites
