More problems with my 90" mower- need advice

[woodlandfarms]

OK, So first there is this weird wobble that has started. Only appears at mid speed. It is coming from the main motor. this is a fairly new mower.

4 things I have noticed

I don't think it is bearings. It seems tight to the pull and twist.

The belt has a thin spot. It looks like the best is stretched in a spot. Does anyone know what size of belt this is? Would the thin spot cause a vibration.

My lovejoy is breaking apart. The rubber is cracking. I don't think it is age related. could this be the cause?

Finally, in looking at the lovejoy, I noticed the motor and the lower joy are not aligned perfectly. When the machine was delivered, the motor was loose. I just wrenched it on, and maybe the motor moved abit. We are talking a 16th of an inch out of alignment.

thanks for the advice. I have to order a new cylinder tomorrow and am mulling over having a belt and coupler thrown in the shipment.

Carl

 

[toy]

Woodlandfarms the lovejoy coupling needs to be in alignment as close as possible to reduce the wear on it. If I was going to make an order anyway I probably would get the belt also, unless you know the correct size of the belt already. If I did order the belt I think I would record the correct size of the belt so the next time I could buy it locally, that is since you think the belt might be stretched already. Could there be something that fouled the blades so that they couldn't spin that might have caused the worn spot? I am sure that you removed the belts before you tested for wear on the bearings. I think the lovejoy coupling is for load shock protection rather than to compensate for a miss alignment issue.

 

[J_J]

Carl,

Have you tried a strobe light on the coupling to see if the alignment is correct or moving/shifting. Paint a white mark on the coupler. When the strobe is showing only one spot, the rpm is correct. As you vary the rpm, you will have to adjust the strobe to match the rpm. If the rubber disk is brittle, it may be worn, and will cause a vibration. A worn belt will also cause a vibration. You might look for one of those Kevlar stranded belts that will bend good on the front and back side. The idler tend to bend most belts backwards.

 

[MossRoad]

On my 60" deck a few years ago I had a big wear spot on the belt. As someone mentioned, it looked like the belt was held in place while a wheel tried to spin it, causing several spots that were concave. 3/4 of the thickness of the belt were missing in those spots. And it did cause a vibration.

The best I can figure is I probably tried to engage the deck while the blades were stationary in heavy wet grass, causing the deck motor pulley to grind some low spots in the belt.

 

[ponytug]

Carl,

Lovejoy couplers need to be very accurately aligned. 1/16" of an inch is a lot of play. Don't forget that you are also trying to align the axes of rotation as well, so you want the two spindles (motor and mower) to be co-axial. Any mismatch in alignment (laterally or axially) will chew up the spider in the coupler and the coupler itself.

I would second MR on the worn belt. It will certainly setup a vibration, as will a wearing Lovejoy.

All the best,

Peter

 

[toy]

Sometimes when you run a love joy coupling when the shafts are misaligned it will cause the rubber part to get hot and you can smell a rubber burning smell, but you could possibly get the same smell if the belt was slipping on a spindle especially if the belt was tight and the blades were somehow fouled as MR mentioned in the tall grass. The love joy couplings purpose I don't think is to make up for a sloppy shaft alignment but instead to absorb shock. By the way the belt jumping off and getting fouled under the pulley will cause belts to wear a spot on them or even cause them to break guess how I know, my Craftsman gt taught me that.