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Discussion Starter · #1 ·
Hi, first post here...wow lots of info too.

I just became the owner of a 1990 ranch king/mtd mower with 18horse briggs and a 46in deck.

This is my first rider ever, im a pretty decent mecanic but have no experiance with riders. Rescued this bad boy from a chicken coupe in southern il...to my knowledge is has been sitting for 10 years.

Anywhoo did the usual fluids/filter/plugs and tore down the carb and put it back together. it fired on the fourth crank too! when i'm mowing, it seems ok in first gear, but the higher gear you put it in (its a 5 speed) it jerks. it acts like you push the clutch in and then pop it back out. if you lift the deck and shut off the pto, it almost goes away....ut not completely. I don't know how to tell if its the belt slipping, and frankly I've spent 60$ getting it running now, I'd hate to spend another 50 on a belt to find out the rear end is junk..

what do ya'll think? Belt or bad tranny/rear end?
 

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First welcome. I have the same mower but MTD branded with the 14speed trans. Been a great mower. I would guess that the variable speed pulley is sticking. It looks like a double pulley in the center of the mower. Belt runs from the engine to the bottom sheave and the top belt runs from the top sheave to the transmission. As you change speeds the center of the pulley moves up or down to change speeds. Bad news is after sitting that long you may have to change the belts. If you don't have a book on it,let me know and I'll copy mine and try to email it or will use snail mail.
Aaron
PS got relatives in that area dad was born there
 

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:MTF_wel: Have the auto drive on my MTD. Make sure that center sheeve is running free and not sticking. Bearings can also go bad on these. If you find the bearings are bad can get replacements from a bearing supply house usually cheaper than buying from a lawn mower parts house. Just take in the old bearing and they can match it.
 

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Discussion Starter · #4 ·
First welcome. I have the same mower but MTD branded with the 14speed trans. Been a great mower. I would guess that the variable speed pulley is sticking. It looks like a double pulley in the center of the mower. Belt runs from the engine to the bottom sheave and the top belt runs from the top sheave to the transmission. As you change speeds the center of the pulley moves up or down to change speeds. Bad news is after sitting that long you may have to change the belts. If you don't have a book on it,let me know and I'll copy mine and try to email it or will use snail mail.
Aaron
PS got relatives in that area dad was born there

dude..heck ya a manual would be great, my email is [email protected] if you can mail it.

2nd I dont see a variable speed pulley, of course I'm a rookie so I may not know what im looking at. there is only 2 belts on the mower, one runs the deck and one runs from the crank around 3 spring loaded idlers (attached to the clutch linkage) then to the back. the belt is loose enough that in the middle of the mower, I can touch both sides together with little effort. All the pulleys seem to be just normal pulleys.

I sprayed the belt with belt dressing and was able to get a smooth 1st, 4th, and 5th gear out of it, but 2nd and 3rd still jerk real bad.
 

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If it is a variable pulley drive you would have a pedal that works much like a hydrostatic drive - the harder you push the faster you go. If you just have separate gear settings and a clutch pedal then it is a gear drive and you wouldn't have a variable pulley.
 

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Discussion Starter · #6 ·
nope, not hydro. it works as a clutch/brake. As you push it in, the gear disengages, if you push it farther the brakes work.
 

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Discussion Starter · #7 ·
so with the pulley out of the way now what? belt? or could this be worse...somthing in the rear end?
 

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Discussion Starter · #8 ·
ok, maybe its older than I think...I can't even find an internet pic of one...anyway heres some pics of mine< maybe this will help..













 

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It's a 1989 model 752, and your right it's a 5 speed. Put it in any gear without it running and check the belt tension. Also check the belt condition ,make sure there are no chunks out of it.

Then if it that checks out, take the belt loose and check the idler pulley. It could have bad bearings.

If that checks out put the belt back on and check the clutch pedal adjustment.

If you still have trouble please post back any questions.

I don't know if you have the manuals for your tractor, but heres a link to them.

http://manuals.mtdproducts.com/mtd/...=true&langId=-1&model_num=139752&serial_num=1

Walter
 

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Discussion Starter · #11 ·
wow..great info, thank you so very much.

I printed out the manual and read some...it does not say how to adjust the clutch or if it was even possible. I do notice it lets out all the way at the end which makes me think the belt is stretched and slipping...i guess since first gear is so low, the belt slipping just doesn't affect it much.

I don't know if it matters, but when the clutch is out all the way, the idler is pushed as far as it will go, as in, it sits in the same place it would if there was no belt at all. Is that normal, or should it not be able to push the belt that far?
 

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Looks like the clutch rod is not adjustable. But the brake is. If you put it in nuetral with the brake off is it easy to push. If it's hard to push the brake is sticking.

If the belt is slipping, let the clutch out faster. You will be able to tell easier.
Make sure all the idler bearing spin free.If they catch at all they get worse as they get hot.
 

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Discussion Starter · #13 ·
Looks like the clutch rod is not adjustable. But the brake is. If you put it in nuetral with the brake off is it easy to push. If it's hard to push the brake is sticking.

If the belt is slipping, let the clutch out faster. You will be able to tell easier.
Make sure all the idler bearing spin free.If they catch at all they get worse as they get hot.

I'll check all of that out this week, thanks. If you dump the clutch, it will just sit there for a few seconds then it will go.
 

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I'd ensure that brake rotor/disc isn't all rusty or pitted--after a 10 year nap,its likely its pretty rusty,and in the lower gears,it might not be noticeable,but in the higher gears with faster speed,and rust "grabbing" on the brake pads might give you that "jerky" sensation your describing..the disc I'm talking about is in the picture before the one showing your model numbers..
 

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Discussion Starter · #15 ·
great point it is rusty and pitted, but moves very freely while in neutral. I have to push the pedal all the way down to get the brake to work and it wont hold on a hill, so i think it will definatly need brakes.

on a side note, I mowed my sisters yard yesterday and she has hills, I noticed when pulling up hill, it jerkes in first gear also, but stops on level ground. The spring loaded adjuster is all the way over as far as it will go, like it would sit in he same spot whether there was a belt on it or not, and the belt has alot of slack in it. I don't know what it should look like, but I assume it should be alot tighter than that.
 

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go out and get yourself a new belt for it bcause with the clutch pedal all the way out the idler should have some room to move still to compensate for belt stretch but from what your describing the belt has streched too much and the clutch idler can no longer compensate for the added legnth of the streched belt. a new belt should stop all the jerking
 

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Discussion Starter · #17 ·
replaced the belt and inspected all of the pully's and nothing has changed...still jerks just as bad as it did...i'm so angry that my free mower has now turned into 168$ of mistakes....

while mowing yesterday I now notice a distinct "pop" from the transaxle as it jerks....i'm guessing my problem is in the rear end/transaxle...any ideas where to start? im almost into this to far and too much money to turn back now..
 

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Might check the mounting bolts holding the transaxle onto the chassis,if they were loose it might let it slop around enough to affect belt tension and alignment..sounds like the idler pully wasn't tightening the belt enough before,if it ran out of travel with the belt on--it should go another inch more if the belt is off,in my opinion..

Sometimes rust in the pulley sheaves can cause grabbing and or slippage too..
if all else checks out,I suppose it could be an internal problem in the transaxle..I dont know if the 5 speeds had a chain inside or not,if it did and was loose,that could cause the jerking ..but a lot of these "variable speed" setups were never that great ,even new they didn't always work right..
 

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is the new belt the OEM recommended or did you match up the old belt? If you matched up the old belt you may have a belt that's to long. The tension pully should not be against the stop when the clutch is released, if it is try a shorter belt. Also if the new belt is not as wide it will go deeper in the pulleys which could make it too long.

You could raise the rear wheels off the ground and try turning the pully on the axel by hand and see if you feel the jerk that way, if so you may have a gear inside with teeth broken.
 

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Discussion Starter · #20 ·
sorry for not explaining..

I bought an origonal MTD belt, ran me 48$ and some change, the tensioner is tight now and prolly about 1 inch off the stops.

it is not a variable speed trans, only 5 gears..

the mounting bolts on the rear are tight.
 
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