Lawn Mower Wheel Drive slipping?

[Hysteresis]

I bought a Fielder Lawn Mower from Mowers Direct a few years ago. I see Mowers Direct are now out of business (I think).
The drive to the wheels has been failing/slipping for a while, but has now completely stopped driving the wheels. The nature of the failure suggests the Drive Belt (If it has one) is slipping, I have had a superficial look at the underside of the machine but I can't locate any Wheel Drive Belt adjustment to tighten the Belt. Other than stripping the whole machine down, does anyone have any ideas if there maybe some easy way to tighten the Wheel Drive Belt on a bog standard cheap and nasty Lawn Mower, I suspect a new lawn Mower is the answer, but it will definitely not be a Fielder.

 

[foxhole]

Some have drive belts some chains.
Lots of YouTube videos showing how to repair.

 

[Burnerman]

Tip the machine right back on its handles (not on it's side!)
Is there a plastic cover that hides the belt, between the blade and the engine?
Fieder machines usually have a gearbox that is tensioned by a spring, but first things first!
John

 

[Hysteresis]

Some have drive belts some chains.
Lots of YouTube videos showing how to repair.

Thanks Foxhole. There were some good videos on there. After reviewing a few I think my problem is the wheel drive gearbox. It probably has a Plastic drive arrangement, all you can really expect from a cheap and nasty lawn mower. I cant remove this gearbox cover and will need to maybe drill the retaining screws out. Hardly worth the effort to effect a repair which will probably require a new drive gearbox. The You Tube viseos were very informative, thanks for the tip.
I think a new lawn mower is the answer.

 

[Hysteresis]

Tip the machine right back on its handles (not on it's side!)
Is there a plastic cover that hides the belt, between the blade and the engine?
Fieder machines usually have a gearbox that is tensioned by a spring, but first things first!
John

Thanks John, There is indeed a plastic cover. I think the problem is the wheel drive gearbox which I think has a Plastic drive cog. I cant confirm this as I cant get the cover of the Gearbox to have a look. To much arsing around for a cheap and nasty lawnmower which will probably fail with something else in the not too distant future. I have never really been happy with this machine so I think it is destined for the Scrap yard although is is only about 5 years old. Good engine which starts every time. Thanks for your advice.

 

[yorksbuilder]

I have had a mountfield 180 for 11 years, Briggs & stratton engine. The self propulsion failed about 7 years ago or so, so took off the plastic cover on bottom by rear wheels, drive belt was worn through. Bought a replacement online and fitted it and its been fine since then

 

[Hysteresis]

Thanks John, There is indeed a plastic cover. I think the problem is the wheel drive gearbox which I think has a Plastic drive cog. I cant confirm this as I cant get the cover of the Gearbox to have a look. To much arsing around for a cheap and nasty lawnmower which will probably fail with something else in the not too distant future. I have never really been happy with this machine so I think it is destined for the Scrap yard although is is only about 5 years old. Good engine which starts every time. Thanks for your advice.

I had another look at the problem, I ended up at the Drive shaft and the wheel drive pulley wheel which drives the belt which in turn drives the wheel gear box. After dismantling and detaching the wheel drive pulley, I noticed that the only thing securing the wheel drive pulley to the drive shaft was no more than a minute grub screw. Looking at the design there looks to be a requirement for a steel key required to secure the drive pulley to the drive shaft as there is a keyway in the drive shaft. This key way is used to locate the cutter blade shaft to the drive shaft. I could not find a key to insert in the Pulley boss to secure the drive to the wheel drive gear box. I of course may have lost the key to secure the wheel drive pulley to the engine drive shaft when dismantling the unit or there was never a key in there. Search as I could, I could not find any key, if it was ever there.
I hope this lot is making sense!!!!!!
So the question is, if there was supposed to be a Key to secure the wheel drive pulley to the drive shaft I need to get another one or some how make one. Have you any idea where I may get a key for this function. I Have used the minute grub screw to tie the pulley and drive shaft together. I reassembled every thing and the wheel drive function of the mower worked although I doubt it will be for long as the minute grub screw is the only thing securing the drive to the the belt which drive the wheel drive gearbox.

 

[Harry Bloomfield]

So the question is, if there was supposed to be a Key to secure the wheel drive pulley to the drive shaft I need to get another one or some how make one.

They are known as a Woodruff Key. Sometimes a half moon shaped piece of steel, which mates with the drive shaft, sometimes just a parallel sided part.

 

[Burnerman]

There's always some sort of key that connects the engine crankshaft to the aluminium boss that holds the blade. Often they get lost when dismantling! A firm called GHS Ltd will be able to fix you up I should think. I'm not sure about the grub screw though, can you give us a pic do you think?
John

 

[Hysteresis]

There's always some sort of key that connects the engine crankshaft to the aluminium boss that holds the blade. Often they get lost when dismantling! A firm called GHS Ltd will be able to fix you up I should think. I'm not sure about the grub screw though, can you give us a pic do you think?
John

Thanks for your reply John. I reassembled the Mower and it all worked although as I suggested the longevity of my effort is in doubt. The reassembly was really to determine If I had Identified the problem. To clarify, the aluminum boss involved, it is the boss that the wheel drive belt uses to drive the wheel drive gearbox. When I dismantle the mower again I will post a picture. Harry Bloomfield suggested it was a Woodruff Key is not quite correct, a Woodfuff Key is the Half Moon Key, this one will be the plain and simple Square key. I do think I have Identified the problem and will have another look to see if a square key will do the trick. On reflection, I think there may be very little machined Keyway in the drive shaft to accomodate a square key. I must say though, I didn't take a close enough look, as at that stage as I did not know if I had identified the source of the problem. Hindsight is a wonderful thing. The grub screw I mentioned is a very small one, too small to do any serious grip on the drive shaft, quite what the function is debatable, maybe to just hold the boss in place whilst inserting a square key????
Thanks so much for your help.

 

[Burnerman]

Looking forward to hearing about the outcome!
Indeed, the woodruff key is typically half moon in shape, the flat key is called a feather key (with slightly rounded ends) and the list goes on, including a gib key which has a clubbed end!
For sure, the engine crankshaft end will be parallel with a key slot cut in it, the boss may have the corresponding slot in it, or even part of the casting.
Either way, the boss needs to be tight on the crankshaft, and on the other (gearbox axle) end the pulley is usually connected using a roll pin.
John

 

[Harry Bloomfield]

Harry Bloomfield suggested it was a Woodruff Key is not quite correct, a Woodfuff Key is the Half Moon Key,

Which is what I actually said, and named the part!

this one will be the plain and simple Square key.

I didn't give the square type key a name, because I didn't know the correct name. I didn't suggest they were called a Woodruff Key.

 

[Hysteresis]

Looking forward to hearing about the outcome!
Indeed, the woodruff key is typically half moon in shape, the flat key is called a feather key (with slightly rounded ends) and the list goes on, including a gib key which has a clubbed end!
For sure, the engine crankshaft end will be parallel with a key slot cut in it, the boss may have the corresponding slot in it, or even part of the casting.
Either way, the boss needs to be tight on the crankshaft, and on the other (gearbox axle) end the pulley is usually connected using a roll pin.
John

Hi John, Mower Fixed and running as new. The problem was that there appeared to be no square Key in the Wheel drive Boss and was relying on the Small Grub Screw to hold the boss to the drive shaft, or maybe the key had dropped out at some time. I attach the photographs for your information. Mower Boss 1 shows the boss in place on the mower blade Drive shaft without the Square key in Place, Mower Boss 2 shows the Home Made Stainless Steel Key in place. When the Mower Blade boss is put in place on the drive shaft, the Blade Boss fits closely up to the home made Key and as such should prevent the key coming out. When I get the opportunity I will try to find a supplier for a proper manufactured key, but I think that will be difficult to locate. Mower Boss 3 shows the Small Grub Screw to which I previously referred.
My mower is up and running now, it remains to be seen as to how long my 'Botched Key' survives.

 

[Hysteresis]

Which is what I actually said, and named the part!



I didn't give the square type key a name, because I didn't know the correct name. I didn't suggest they were called a Woodruff Key.

Hi Harry, May I sincerely apologise for misinterpreting your very Helpful comments, which were very helpful to me, Thanks again.
My misunderstanding was simply that your comment suggested Woodruff was a generic Name for ALL keys and not specific to the Half Moon shaped Key. So sorry if the misunderstanding offended you, that was certainly not intended.
This website has so much helpful advice from people such as yourself. I would hate to offend any of our tremendous contributors.
Thanks again.

 

[Harry Bloomfield]

When I get the opportunity I will try to find a supplier for a proper manufactured key, but I think that will be difficult to locate. Mower Boss 3 shows the Small Grub Screw to which I previously referred.

I wouldn't bother - that SS key, is much tougher than the cast-alloy pulley it is driving. The pulley will collapse long before the key.