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Discussion in 'Lawn Mowing' started by turfcat75, Apr 29, 2001.
can anyone tell me how to change the drive belt and blade belt,or have a site with some info?
I have a 36" Exmark hydro and have changed both the mowing deck belt and the hydro pump belt after each of the five seasons the machine has been used. It is not difficult.
I back my machine onto auto ramps so that the rear of the machine is high. I change the hydro filter at the same time - much easier to get access with the wheels six inches higher.
If you have a 48" machine, then you have two mowing deck belts. My 36" machine has a single belt. The second belt on the deck itself should be simple. The belt from the motor should be similar to my 36" machine. Take off the engagement idler so that there is plenty of free length on the deck belt. Also, there are two belt supports under the engine, supports that keep the belt in the motor pulley when the belt is disengaged. These are bolted to the underside of the engine deck, a strip of metal with a short length of rod that sticks downward. The rods are the parts that keep the belt in the pulley groove. Just loosening the brakets will enable you to swing them out of the way so that the belt can drop down. Take out the old belt.
Now, take off the hydro pump belt. Disconnect the spring that holds the tightener idler. You need more ample slack from the idler and removing the spring is the best way. The spring is strong, so be careful. I believe I use a large Vice-Grips to grab the spring and then rotate is enough to take if out of the hole in the bracket. After the spring is gone, the idler will move freely and the belt will loose enough to be removed.
At this point, I suggest that you swing the idler back and forth several times, AND grease the fitting on the post. The motion on the post is so small that it may get bound up over the course of the season. During cold weather, I use the cold start release. This is the ring/chain that comes off the right side. Pulling the ring and attaching it to the bolt head will release the idler, loosening the belt so that the pumps don't operate. When cold, the drag from the hydro pumps is significant and makes engine starting much harder.
Anyway, be sure that the idler bracket freely moves on the post, get it greased. I grease mine at least once per week during the entire season, and then exercise the cold start chain/ring several times. This is just to keep the bracket moving freely on the post.
The install of the two belts is basically the reverse of the removal. Install the upper belt first, the hydro belt. Get the idler spring reattached.
Before installing the mowing deck belt, swing the idler bracket several times on the post. This is the same situation as the hydro idler bracket. It does not rotate very much when engaging the deck drive. Therefore, it may bind up. This is the best opportunity to be sure that it moves freely. Grease the fitting while makes the swings.
Intall the mowing deck belt. Be sure to adjust the belt tightener to a large extent before getting it back into place. This will make the belt adjustment very loose when assembling. The takeup shank (square, with a lock nut) has at least one-half inch of leeway. Put the engagement idler back, and tighten. Now you can adjust the belt tension with the adjustment screw (square shanked part). Lock into place with the lock nut.
Return to the rear of the mower and reposition the guide posts that were loosened and swung out the way. The posts cannot rub on the belt when in running mode, but must be close enough to the outside of the belt that they help make a loop around the motor pulley when the mower deck drive is disengaged. If they aren't positioned right, the mower deck belt will drag a bit, and the blades may not quite stop running. The posts assist in making a loose loop around the pulley.
I've written all this from memory, so I hope I've not missed something. I'm pretty sure that the mower deck pulley is on the bottom, and the hydro pump pulley is on next to the engine. If I'm wrong, please excuse. However, the procedure stated above will have be modified slightly, only in the sequence of belt removal. I apologize if I've misled because of a faulty memory.
BTW, when doing the mower deck belt replacement, this is your only chance to grease the fitting on the engagement crank. The idler is in the way in the normal position. But, while it is taken off, there is a clear path to the fitting. Well - a clear path may be stretching the point a bit! I cannot grease the fitting with a straight pipe on my grease gun. I have a flexible hose that I install on my gun so that I can reach that fitting. Despite what the book says, this is the only time each season that fitting gets greased on my machine!!! What a dumb design. It is very difficult to reach to grease. I can't even see the fitting. Getting the grease gun to the fitting is done by feel.
I hope all this helps. Sorry for the length, but I didn't want to leave out any steps. If somebody things I'm wrong on any point, feel free to correct.