Einhell petrol mower GC-PM 46/3 S drive

[JohnW2]

Hi there, I'm a bit confused, so I wonder if anyone can help!

II have an Einhell GC-PM 46/3 S self-propelled petrol mower, which is 2-3 years old. It's been generally working fine, but recently the drive belt has started coming off. This belt goes between the 'camshaft' pulley (behind the blade) and a pulley on the 'gearbox' which is attached to the rear axle, to drive the rear wheels.

In trying to fit a new belt, I find (to my surprise) that the gearbox is sort-of 'floating' - free to rotate around the rear axle, with no spring, bracket or whatever to maintain tension in the belt, and no evidence that there ever was anything like that.

Does anyone know whether this mower (or a similar one) is meant to have such a 'floating gearbox' and, if so, how that us meant to work?

Kind Regards, John

 

[Burnerman]

These axles do float to some extent - this controls the belt tension - but the axle gearbox should have some sort of spring mechanism to keep the belt tight.
I don’t know this particular machine but it sounds like a spring has vanished.....maybe rusted through?
Often there is a hole in the gearbox casing that holds the spring end.....is there anything similar on yours?
John

 

[JohnW2]

These axles do float to some extent - this controls the belt tension - but the axle gearbox should have some sort of spring mechanism to keep the belt tight.

Thanks for your interest. That's what I was expecting to see, but ...

I don’t know this particular machine but it sounds like a spring has vanished.....maybe rusted through?

Again, that's what I expected, but can find no evidence that there was ever any spring (or bracket/adjuster, or whatever) attached at the gearbox or, at the other end, to any part of the machine

Often there is a hole in the gearbox casing that holds the spring end.....is there anything similar on yours?

See above - I can't find anything. I'm not sure how useful they will be, but I'll attempt to take some photos tomorrow.

Kind Regards, John

 

[jj4091]

https://www.einhell-service.com/en_GB/3400727-gc-pm-46-3-s.html Item 43 says it is a tension spring

 

[Burnerman]

That's exactly the sort of thing I was trying to describe......one end hooks onto the transmission somewhere, the other disappears towards the cutting deck (machine inverted).
John

 

[JohnW2]

https://www.einhell-service.com/en_GB/3400727-gc-pm-46-3-s.html

Over the past few days, I have become very familiar with that list of parts and the associated (unfortunately very low resolution) 'exploded diagram'

tem 43 says it is a tension spring

It does. That appears to be the return spring on the lever on the gearbox which is operated by the clutch cable- and that spring is still present.

I cannot find any other possibly-relevant spring in that list of parts (can you?), nor any evidence of where a spring could ever have been connected to either gearbox or the body/deck of the mower.

Kindest Regards, John

 

[JohnW2]

That's exactly the sort of thing I was trying to describe......one end hooks onto the transmission somewhere, the other disappears towards the cutting deck (machine inverted).

It's exactly what I was expecting to see, too, but see my reply to jj4091

I have tried, so far with no success, to get advice and/or a service manual from Einhell. Things initially looked promising, in that they acknowledged (in a message which did not look 'computer-generated') by query, and said that they would respond 'soon', within an hour or two - but a couple of weeks and a couple of further'jogging' e-mails later, I have yet to hear anything!

Kind Regards, John

 

[Burnerman]

That tension spring is bloomin' big for the dog clutch lever.......could you possibly give us a photo or two of what you have - machine on it's back?
Regards
John

 

[JohnW2]

That tension spring is bloomin' big for the dog clutch lever.......could you possibly give us a photo or two of what you have - machine on it's back?

I'm about to try to take some photos, but it won't be easy - so 'watch this space' !

In the meantime, these poor (low res) images (of the "transmission") are from the Einhell website ...

Enlarging the middle one (showing the 'back' (upper, when standing on its wheels) side of the gearbox just about shows the spring in situ (I would add that mine looks slightly different from this pic) ...

Kind Regards, John

 

[JohnW2]

OK, my first stab at some photos. The first couple show the extent to which the gearbox will currently rotate on the axle - were it not for the clutrch cable and the bar joining the two rear wheel mounts, it would literally go 'round and round' the axle ...

This next one is about the best I can do (without a lot of dismantling) to show the 'back' ('top') of the gearbox - with part of the 'tension spring' visible ...

Kind Regards, John

 

[Burnerman]

On your first photo I notice a drilled hole next to an Allen screw.....could that be where a hooked end of a spring could locate?
John

 

[JohnW2]

On your first photo I notice a drilled hole next to an Allen screw.....could that be where a hooked end of a spring could locate?

Do you mean gthe hole indicated here? .....

... if so, then, yes, I had a similar thought, since ithat is the only hole/bracket/whatever on the gearbox I can see to which a spring could have been attached. However, there are two "buts" ... firstly, a spring from there to tension the belt would have to go 'backwards' ('into the photograph') but it's route would then be perilously close to (if not blocked by) the pulley and/or belt ...

.... secondly, I can see nothing on the body of the machine behind the gearbox to which the other end of a spring could have been attached ....

I suspect that I am going to end up having to improvise some sort of 'bodge', but would have liked to do something which at least approximated to the original situation - if only I could work out what that 'original situation' was!
Given the issue of the pully and belt, I suspect that I'll probably have to somehow attach a spring to the 'other side' (left in the photos) of the gearbox and having the other end of it attached somewhere to the back of the machine's body.

Any other thoughts/suggestions?

Kind Regards, John

 

[Burnerman]

For sure this is an interesting one! That was the drilling I was on about but to be fair, there wasn’t any sign of a truth mark where the spring would have been.
Anyway, the axle has to be retained one way or another and naturally it would tend to be pulled towards the engine.
Most retaining springs are actually vertical from the axle up into the voids of the metal deck.....Honda technique anyway! Some designs have a rod connected to the axle which passes through the deck where the grass box is - the rod being threaded and often spring loaded.
Unless we can find an identical machine I guess it’s bodge time to somehow pull that axle towards the rear of the mower, but I can’t suggest anything else unfortunately.
I do think that tension spring that jj found has something to do with it though......it’s just too long just to be a clutch release device.
Regards
John

 

[JohnW2]

For sure this is an interesting one! That was the drilling I was on about but to be fair, there wasn’t any sign of a truth mark where the spring would have been.

Indeed - quite apart from the pully/belt 'being in the way', I would have thought that there would be some tell-tale marks there had there been a spring going through that hole.

Anyway, the axle has to be retained one way or another and naturally it would tend to be pulled towards the engine.

Quite so. That's obviously the problem I have, and need to rectify. The mower is relatively young and otherwise fine, so I would be very reluctant to throw it away, and to get it 'professionally repaired' (if I could) would probably not be very 'cost-effective'!

Most retaining springs are actually vertical from the axle up into the voids of the metal deck.....Honda technique anyway!

A spring going from that hole we've seen would, of course, be 'vertical'when the mower was on its wheels - but, for the reasons that have been discussed, I can't see that there could ever have been a spring there.

Unless we can find an identical machine I guess it’s bodge time to somehow pull that axle towards the rear of the mower, but I can’t suggest anything else unfortunately.

Indeed. I had obviously hoped that I might find someone who has got an identical machine, so they could look and tell me how it is meant to work!

As you say, I need to pull the gearbox towards the back of the machine, and that will require a 'horizontal' spring, somehow attached to the rear of the 'rear' (left in photos) of the gearbox. I may possible be able to use the same lug that the existing spring goes through or, alternatively,attach some sort of bracket using one of those allen screws. .

I do think that tension spring that jj found has something to do with it though......it’s just too long just to be a clutch release device.

Maybe, that spring in Einhell's list is just over 9 cm long, and I would have guessed that the one on my machine was probably 7 or 8 cm. However, I'll have a go at actually measuring it tomorrow, and will report back.

Many thanks for all your interest and attempts to help!!

Kind Regards, John

 

[ericmark]

We also had a problem with drive belts on a ride on mower. shown here parked in the disabled parking bay, showing the blue badge as a joke. But what we found was there are a lot of imitation belts on the market, they look the part, but will either come off, or break, we have a second mower at the station the other end of the line, and that one works A1, but the belts on the one shown never seem to line up correctly. Belts seem to have a problem lasting one season.