Drive belt tension adjustment for Mountfield R28M

sujsuj

I recently made some adjustment to drive belt tensioner and somehow after that when I switched engine on blade started rotating without even tensioner/cutter deck  engaged. Basically when engine runs cutting blade also started rotating. This also resulted in burning the belt and now I bought new belt!!. I am just wondering what all adjustments I need to do to ensure only enough tension on the belt..?

Also when tensioner is not engaged , which all drive pulleyes  expected to rotate..?
We have Pulley-1 connected to Engine, Pulley-2 connected to cutting blade Pulley-3 connected to tensioner/cutter engager. I suppose when cutter is disengaged only pulley-1 expected to rotate..? what will happen to the belt when pully -1 rotates but other are not..?
When cutting deck is engaged, Pulley-3 will push belt and increase tension to start rotating all 3 pulleys. Is this the right way pullies work..?

Any help which adjuster I need to move to resolve above issue. See photos.. Thanks very much

ThisIsWeird

Anyone brave enough to go here?



I see another 15-pager.

ThisIsWeird

In short, SS, and as you surmise, that appears to be a very crude system which relies on the belt slipping when the jockey pulley isn't pulled into tension. Clearly there will be some wear taking place on the belt whenever the engine is running and the wheel disengaged and the belt slipping.

It's also a solid reason why you never work in that area with the engine running, even on tickover...

Anyhoo, since you clearly understand how this works, I am hoping you'll make the quantum leap to figuring out what set tension is ideal. I'm guessing you slacken it until the blade stops spinning, and then perhaps a turn more? Something like that. Ie, where the blade stops spinning when the lever released, and engages firmly (that compression spring is nicely squished) when pulled. 

There will almost certainly be a reasonably wide 'sweetspot'; find it, and stick it in the middle.

And, contact the mower manufacturer and ask them too.

For my sanity, that'll have to be my last word on this thread

Section62

ThisIsWeird said:

Anyhoo, since you clearly understand how this works, I am hoping you'll make the quantum leap to figuring out what set tension is ideal. I'm guessing you slacken it until the blade stops spinning, and then perhaps a turn more? Something like that. Ie, where the blade stops spinning when the lever released, and engages firmly (that compression spring is nicely squished) when pulled.

Usually the other way round - back the tension off, engage the clutch, then add tension until the belt has the correct amount of 'play' in it.  The amount of play will depend on the type of belt and belt length, usually something the mower manufacturer will specify in the service manual... or something a professional mower repairer will know. About 1/2 to 1" is typical on longer belts.

If the belt tension is correct when the clutch is engaged, then by design it should be sufficiently slack to minimise wear when disengaged.  If the belt doesn't have sufficient slackness when disengaged (with the tension having been set correcty) then it points to either 1) The wrong length of belt being used or 2) something has been taken apart and not reassembled correctly. Either of these are a strong possibility if the mower is still burning through belts.

ThisIsWeird

Phew - S62 is here :-) I look forward to the next few weeks as you are asked to explain the minutiae.  

sujsuj

Thanks very much..

I think I am getting there with adjustments, one doubt still I have is when cutter deck is dis-engaged that point only the pulley connected to engine will rotate. But it got a belt in it which doesn't rotate...is that the way this is supposed to work...?
 Because this could damage inside of that belt right as pulley is rotating and belt is not as cutter is disengaed and no tension in the belt...Thanks

ThisIsWeird

Over to you, S62 - I'm watching

Dustyevsky

You didn't do as I suggested and get it on eBay while you were winning!

Having said that, there was a loud clang last night as a pulley wheel fell off my Countax and I then ran over it. I paid north of £500 for a repair and service a few months ago, or in mower running time, about 5 hours. So, I'm hoping the machinery place takes some responsibility.

I've not yet had a mower that will run all season and doesn't need something doing. What's more, I don't know anyone else who has achieved that either.

sujsuj

All sorted..... Basic issue is first year I got  ride-on delivered in June only. By that time grass was 0.5 to 1 m high. Then I had to use trimmer to get grass short before using mower. may be attempted many times beyond its capacity. Last year nearly all went as planned so didn't face much issues, but towards end of year drive belt was damaged.. This year  I took till May to get drive belt sorted, then I had oil leakage issue. Again grass grown to 0.5 m which my Mountfield can't handle. So again I had to trim grass before using mower.Thats why I said I used mower roughly, beyond its capability. hopefully next year it will be better.

Thanks everyone.