I just put a speed up pulley, new blades and replaced the belts on 318 my mower deck. The blades seem to spin fine when the deck is all the way up but once i lower it down the blades seem to slow down and don't sound like they are spinning as fast. Any idea why that is? Is it a belt tension/alignment problem? Thanks for any advice.
318 mower slows when deck is lowered
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beenthere
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What do you mean by "speed up pulley" ??
Sounds like you are getting belt slippage.
Sounds like you are getting belt slippage.
Its a differnent size deck pulley that is supposed to speed up the blades:
John Deere 50-inch Mower Deck Center Drive Speed Up Pulley - AM116141
When I lower the deck the belt angle changes and it looks to be longer, wouldn't that tighten the belt?
John Deere 50-inch Mower Deck Center Drive Speed Up Pulley - AM116141
When I lower the deck the belt angle changes and it looks to be longer, wouldn't that tighten the belt?
Gary Fowler
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My Craftsman mower belt started slipping so I put on a new belt but same problem when I hit tall grass. I fixed it (almost) by drilling a new hole in the deck and moving the tension spring about 2" further out so it put a little more tension on the belt. NOW it takes a lot more grass to slip the belt. Might be your problem is the same. I suspect that if you put on a "speed up" pulley that it is a little smaller in diameter so your belt is now too loose. You need to look at the tensioning pulley to see how much pressure it is exerting on the belt. IF you can easily turn the blades by hand, then the belt it too loose. You may be able to do like I did and move the tensioning spring hanger further out if there is room for the tensioning pulley to move far enough to tighten the belt.
You may even need to get a shorter belt than the factory standard.
You may even need to get a shorter belt than the factory standard.
Yellowfever440
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If i remember correctly the stick on the front mule drive shows that you set belt tension on a 318 when the deck is down.. the deck moves forward when being lowered and that males the belt loose. So you set the tension with the deck down so the belt is as tight as it needs to be when mowing.
1Mcgyver1
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I had the exact same thing happen on my Cub Cadet 1527. First I replaced the belts on the deck, then the belt from the deck to the PTO.
No change. Then I replaced the tension spring on the deck, and the spring to the PTO. Again no change.
I had read that maybe my PTO clutch was going bad, but discounted that since it was engaging.
Finally I bought the bearings for the decks two blade spindles, and the bearings for the double pulley. Also the plastic seal cup for the spindle bearings.
That finally did the trick! Now the deck runs like new with no change is speed as I lower the deck all the way from 6 - 1.
No change. Then I replaced the tension spring on the deck, and the spring to the PTO. Again no change.
I had read that maybe my PTO clutch was going bad, but discounted that since it was engaging.
Finally I bought the bearings for the decks two blade spindles, and the bearings for the double pulley. Also the plastic seal cup for the spindle bearings.
That finally did the trick! Now the deck runs like new with no change is speed as I lower the deck all the way from 6 - 1.