PDA

View Full Version : Gravely Belt WB blades spinning fast then slow IDEAS?


Buddha92SLC
04-25-2008, 12:12 AM
My old gravely belt drive WB has something happening with the blades. When I engage the pto the blades are spinning but it doesn't seem that they are spinning at their fullest potential. Then today I was mowing a thick lawn, and the blades would slow down almost to a stop where I had to crawl to finish the yard. Is this a belt tension issue? Where else should I look for. it is weird because sometimes the blades sound like they are spinning super fast and other times lagging. Any ideas?

Jay Ray
04-25-2008, 12:49 AM
It might help if you said whether you have an electric clutch or some manual system of blade engagment.

Buddha92SLC
04-25-2008, 12:47 PM
Yeah that would help wouldn't it. It is a manual lever that engages the blades. There is a small ball style switch that the bar pushes in to engage the blades. This is a Gravely WB Pro36 from the 80's probably. It's a tank.

John Gamba
04-25-2008, 02:26 PM
Yeah that would help wouldn't it. It is a manual lever that engages the blades. There is a small ball style switch that the bar pushes in to engage the blades. This is a Gravely WB Pro36 from the 80's probably. It's a tank.

Is the belt Glazed?? Can you post a pic of the belt where it hits the pully??

GravelyNut
04-25-2008, 04:43 PM
Could be that there are worn spots on the belt. Slips when the drive pulley hits that area. Then picks up again when it gets past it. Under no load, the belt gets past the worn area fast enough not to slow down the blade spindle. Belt tension may be weak at those spots also.

John Gamba
04-25-2008, 04:55 PM
Could be that there are worn spots on the belt. Slips when the drive pulley hits that area. Then picks up again when it gets past it. Under no load, the belt gets past the worn area fast enough not to slow down the blade spindle. Belt tension may be weak at those spots also.


Lets not forget about warn Pulleys:) They only grab the OUTSIDE of the belts.With older mowers its good to replace the pulleys,belts and Tension mechanisms.


Dont forget about the Engine pullys :waving:

GravelyNut
04-25-2008, 05:12 PM
Lets not forget about warn Pulleys:) They only grab the OUTSIDE of the belts.With older mowers its good to replace the pulleys,belts and Tension mechanisms.


Dont forget about the Engine pullys :waving:
That is true.:drinkup:

John Gamba
04-25-2008, 05:16 PM
That is true.:drinkup:

I said it wrong. The worn pullys will only grab the "Top" of the side's. Make slip easy:laugh:

Buddha92SLC
04-25-2008, 07:21 PM
Ok this is strange... today when it happened multiple times I grabbed the pto engagement handle and pulled back ever so slightly. The blades picked back up to full speed instantly. Whenever it happened I pulled back a little on the pto handle and it would kick back up to speed. Strange. I'm going to pull the deck cover off and take a look tomorrow. I'll take pictures. I just replaced every belt on the mower last season. I'm p/t so I think the belt is still good. I only have 10 customers. Any ideas where to look tomorrow with this new information?

John Gamba
04-25-2008, 07:51 PM
Ok this is strange... today when it happened multiple times I grabbed the pto engagement handle and pulled back ever so slightly. The blades picked back up to full speed instantly. Whenever it happened I pulled back a little on the pto handle and it would kick back up to speed. Strange. I'm going to pull the deck cover off and take a look tomorrow. I'll take pictures. I just replaced every belt on the mower last season. I'm p/t so I think the belt is still good. I only have 10 customers. Any ideas where to look tomorrow with this new information?



The tensioner.

GravelyNut
04-25-2008, 11:22 PM
The tensioner.
And make sure that all pivot points are lubed so there is no binding.

Buddha92SLC
04-26-2008, 05:11 AM
Thanks for the info. I'll have a look tomorrow. I'm thinking its the tensioner as well. Ballpark how much would that piece be to replace you think?

John Gamba
04-26-2008, 07:32 AM
And make sure that all pivot points are lubed so there is no binding.




The items that pivot probably will need to be replaced.they do get rounded out.

John Gamba
04-26-2008, 07:33 AM
Thanks for the info. I'll have a look tomorrow. I'm thinking its the tensioner as well. Ballpark how much would that piece be to replace you think?



I have no idea? Can you post a pic of the mower?

LawnSharks
04-26-2008, 06:27 PM
Now that indeed sounds like a tensioner issue.

Buddha92SLC
04-27-2008, 06:41 PM
I checked the tensioner and it was doing its job. Checked the belts and the pullies and both looked great. I lubed up all of the pivot areas. Then I noticed this spring that attached to the rod that engages the blade belt. It was at the very bottom of the pto handle under neath the body of the mower. I noticed it didn't have any tension on it even when engaged. Few turns of the wrench and a double nut to ensure it won't back off and I think I've fixed it. We will see this week how it does, but it already sounds like the blades are spinning much much faster than before. Thanks for all the insight guys. Zac

John Gamba
04-28-2008, 06:48 AM
I checked the tensioner and it was doing its job. Checked the belts and the pullies and both looked great. I lubed up all of the pivot areas. Then I noticed this spring that attached to the rod that engages the blade belt. It was at the very bottom of the pto handle under neath the body of the mower. I noticed it didn't have any tension on it even when engaged. Few turns of the wrench and a double nut to ensure it won't back off and I think I've fixed it. We will see this week how it does, but it already sounds like the blades are spinning much much faster than before. Thanks for all the insight guys. Zac

:waving::waving::waving: