Only slow speed

F

fyrekrig

Forum Newbie
I have a MTD 420/30 which I believe is similar to ClubCadet rear engine.
Model 13B226JD308
Serial IB236B20515
DOM 02/16
I recently replaced the flat pulley (Part 756-04224) and drive belt ( Part 754-04331)
The mower was working fine for a few days then in the middle of moweing it started to slow down.
First a little bit slower and then finally very slow.
Have inspected all the belts and can not find the cause of this.
Any comment appreciated
 
With the MTD variable speed pulley system both belts have to be replaced as a set otherwise things don't sync properly and will lead to problems. Also make sure the variable speed pulley isn't sticking in one position which will also limit your speed.
 
Thanks your reply.
The other belt was replaced only a few weeks ago.
Pulled up the mower and started to play with speed settings and realized when I released
the clutch quickly it all went back to normal. Did run the mower up and down our yard and now seams to work.
How is the clutch supposed to work? It does not look like a spring loaded disk as on a car.
Is it possible that it overheated when I stopped and started mowing the lawn?
 
Could be the spring that tensions the belt on the transmission pulley could be getting weak, or the belt idler arms or the variable pulley slide is getting hung up and not moving freely.
 
More testing done!
The brake pedal will not return fully when switch gear and only slow speed.
Only when I force the brake pedal fully back will I have speeds according to gear leaver settings!
As long as I force the brake pedal fylly back I have a normal workin lawnmower!
 
The tension spring that is associated with the engine to variable pulley would be suspect in not providing enough pull to keep the system working correctly.
 
That is the spring. Also something else to look at. The variable speed pulley grooves can get worn and basically act as a speed limiting factor also due to belt hanging up in the worn areas.
 
What options do I have with the spring?
Does it weaken over time? Will a new one solve the problem?
Is stronger springs available?
Any way to increase tension by altering spring fixing points?rod.jpg
Any point of adjusting rod lengh?
 
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The springs do iappear to weaken overtime. A new spring may fix things, but the truth is it could be a combination of things causing the issue. Belts can do weird thing, wear on the stack variable pulley groove cause cause issues on how the belt rides in the groove, and then spring tension not keeping up.
 
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