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View Full Version : why do blades keep running- even with belt loose?


mowisme
04-26-2010, 07:53 AM
I picked up a used Scag and seems the blades keep running even with lever in the 'disengage' position? the belt appears plenty loose in that position too. only thing is been sitting awhile - light pitting in pulley cause this?- thanks

Hoy landscaping
04-26-2010, 08:10 AM
how long does it stay running?

mowisme
04-26-2010, 08:22 AM
They just keep going..as if belt was tight? This is a older STHM so no pulley brake or anything. Only thing I can think of is pulley is not smooth enough?

Hoy landscaping
04-26-2010, 08:36 AM
you disengage the blades and it still does not stop

mowisme
04-26-2010, 09:00 AM
Thats correct HL..they just keep going and going as if belt is tight..but it isn't? I'm thinking either main pulley on deck is not smooth enough..or the one on motor isn't..never seen this before. Belt isn't new but looks ok yet.

Hoy landscaping
04-26-2010, 09:32 AM
does the engage lever work? i have a mower where the blades start spinning when the engine starts but when you engage the blades they spin at normal speed. not sure what happened but im going to leave well enough alone

mowisme
04-26-2010, 09:43 AM
HL..I got the cover off and yes- lever works as should. tightens when engauged- loosens when dis-engauged. Bit baffling. I'm wondering if maybe belt is real loose on deck..but still too tight on motor pulley? I just brought this home so not had a chance to go over it real good. I know it was bit scarey loading it up ramps with blades still running. Thanks on your help. Geno

unkownfl
04-26-2010, 09:49 AM
HL..I got the cover off and yes- lever works as should. tightens when engauged- loosens when dis-engauged. Bit baffling. I'm wondering if maybe belt is real loose on deck..but still too tight on motor pulley? I just brought this home so not had a chance to go over it real good. I know it was bit scarey loading it up ramps with blades still running. Thanks on your help. Geno

Still to tight to fully disengage. Sometimes previous owners install the wrong size belt but you may be able to adjust it out at the tensioner.

44DCNF
04-26-2010, 02:04 PM
See if any belt guides are missing or out of adjustment. Carefully examine the belt path while it is running...you should be able to see where it is grabbing.

Hawg City Lawns
04-26-2010, 02:17 PM
i had an old craftsman rider that did that never figured out what it although i didnt really inspect it too hard i always thought it was a loose belt but i did find out that when you disengage the blades idle the motor down like youre going to shut it off wait til the blades stop then throttle back up that always worked on that thing maybe itll work on yours

mowisme
04-26-2010, 02:33 PM
I think I located the problem folks. (A) the idler pulley has loose bearing and 'wobbles' (B) the linkage is wore bad so the pulley even in the 'disengage' position still bounces back-n-forth in linkage and gets or keeps blades going. I'll fix all that and go from there. I kind of got 'took' on this I think. Motor runs beutiful thou..and suppose to have new head gaskets..but wear in other areas. Its early 90's STHM ($1200) -One of the front wheel arms has the bearing/bushing 'Gone' and hence wore that shaft that yoke rides in right out. ( I can rebuild..but perfer not) Any leads to 'used' scag arms? E-bay has one I'm thinking on. funny thing is..exact same size/shape as my old SW36. Sure shows what happens when lack of maitinence was done. I don't mind the work and can handle the mechanics of it..And I really can get by without it..so is more of a 'project'. I just wanted one as had one few years ago with a original Scag blower on instead of deck- fun to use. I'll most likely only use at Church- don't need with my accounts, all to small for this size (61"). Thanks again- Geno

rosarioslawncutters
04-27-2010, 01:07 AM
do they at least slow down? it could be that the controls might need adjusting, the belt is too small, or bad worn brakes...

44DCNF
04-27-2010, 01:25 AM
Is the caster bracket so hogged out it won't hold a new bushing in? Maybe you could shim one in and align ream it and it would hold.

mowisme
04-27-2010, 07:19 AM
44D.. It might hold bushing..I am contenplating grinding off welds and welding new tubes for bushings on both arms. Not sure where to get that thick of pipe thou?..looks to be double wall thick. I'll take another look when time permits. It has also worn the top and bottom of both tubes on ends of them. just totally crazy they didn't keep up the maitainence. a bushing here or greese occasionally would have prevented this. On the good side: it did run and mow nice when I tried it after getting it home.