What's on your bench today?

[GardenKit]

Interesting - didn't realise they even had one! Presuming it's that black clip type thing? How does it work/move? Does it lift the exhaust valve?

 

Cheers

Yes Mike, most small engines have a decompressor of on type or another.

 

This one is centrifugal, in the first picture the spring has set the lever to 'decompress' and the little metal tag at the top sits alongside the cam lobe but stays proud of the lobe, holding the exhaust valve slightly open.

 

 

As the engine fires and the engine speed increases the small weighted lower ends of the lever are swung out by centrifugal force, which pushes the tag away from the cam lobe so it clears the follower, allowing the valve to fully close.

[mikerecike]

Yes Mike, most small engines have a decompressor of on type or another.

 

This one is centrifugal, in the first picture the spring has set the lever to 'decompress' and the little metal tag at the top sits alongside the cam lobe but stays proud of the lobe, holding the exhaust valve slightly open.[ATTACH]122377[/ATTACH]

 

 

As the engine fires and the engine speed increases the small weighted lower ends of the lever are swung out by centrifugal force, which pushes the tag away from the cam lobe so it clears the follower, allowing the valve to fully close.

[ATTACH]122378[/ATTACH]

 

Brilliant - thank you Barrie

[Rich2484]

Ok. I am in need of a parts diagram for an mtd lawnflite ride on mower.

 

Went out the the lifeboat managers today as he had a problem with his and his health issue has meant he can't work on it anymore.

 

Well the rear drive belt was gone so he had his sone replace it, after it wouldn't run up hills. Well a slope. So looked at it and a bush had gone on a shaft holding the centre pulley assembly. Fine so replaced that. But it is now making a grinding noise when moving.

 

So looked under while it was moved back and forth and the centre pulleys are wobbling. Now looking they look like a variable drive pulley. They take the main engine pulley and another belt to the rear gearbox. With the wobbling the pulley is scraping the metal assembly around it.

 

Now first off there is no movement in the pulleys but they do move up and down on the shaft. Is there any spacers that go between them anywhere and where do they go?

 

So anyone got a parts diagram for this machine? It's a lawnflite MTD ride on, side exit Shute.

[GardenKit]

Rich, with regards to the MTD.

Firstly, I HATE the things.

Secondly, its difficult to offer advice without knowing all the machine details.

 

but, in general terms the variable speed models are tricky to set up. The engine pulley and gearbox pulley are fixed, but the double centre pulley is on a radial arm so it can move forwards or rearwards and the middle sheave can go up or down. The rear belt has a tensioner pulley so dont worry too much about that, its the front one that has to be checked when stopped in fast, and slow gear. It must never be slack.

 

In order for this system to work the belts must be fitted as a pair, and in my experience must be genuine parts.

 

When fitted, the belts will pull either into the top or the bottom depending on the position of the varistor pulley, but at no time must the belt touch the shaft.

 

A bit of playing about will eventually get them right, but they can be a right b**ch to do. Its a waste of time trying unless the belts are new.

[spudulike]

Busy day, got the troublesome Jonnie 2171 going with the Meteor kit now fitted - cleaned the ports and re-beveled to make sure, had to order a new carb boot as the 372 and 2171 are not quite the same and all is good, got 150psi compression without running and it sounds just fine - got to tach on a 20" bar and then ship it out.

 

Also did a quick fix on a 346XP with a fuel leak - the breather had popped out and an MS200t that I had done earlier had ended up needing an accelerator pump mod - now done.

 

Started on a 372XP that is being ported - cleaned it up and now need to get the dremmel and diamond burrs out:thumbup:

[Rich2484]

Rich, with regards to the MTD.

Firstly, I HATE the things.

Secondly, its difficult to offer advice without knowing all the machine details.

 

but, in general terms the variable speed models are tricky to set up. The engine pulley and gearbox pulley are fixed, but the double centre pulley is on a radial arm so it can move forwards or rearwards and the middle sheave can go up or down. The rear belt has a tensioner pulley so dont worry too much about that, its the front one that has to be checked when stopped in fast, and slow gear. It must never be slack.

 

In order for this system to work the belts must be fitted as a pair, and in my experience must be genuine parts.

 

When fitted, the belts will pull either into the top or the bottom depending on the position of the varistor pulley, but at no time must the belt touch the shaft.

 

A bit of playing about will eventually get them right, but they can be a right b**ch to do. Its a waste of time trying unless the belts are new.

 

Glad I'm not the only one who hates them.

 

T he centre pulley is a right pain. The big spring is to user friendly. Took me nearly an hour and LOTS of swearing and bruised hands to get it back on. The pulleys move up and down. Will check if its touching.

 

One bad design on this rode on is no access panel above the pulleys. So with the owners permission going to cut it out and place a panel in bolted down.

 

The belts are new by the way. I'm not really sure what I done but it pulls up a very steep slope easily now. I removed the pulley assembly and added a new plastic bush into the arm, also after putting the belts back on the pedal felt stiffer as if it was actually doing something.

 

Even a simple job like removing the deck was a pain.

 

Just wasn't sure if any shims where needed in the pulleys. And if so how many. His son had replaced the belts before I got there so wasn't sure what he had pulled apart to do it. Really the belts are easy to replace. Rear one is on tensioner idler as you say and the front is held on with a metal guard bolted either side of the engine. So really they are easy to do unless you lose control of the centre pulley assembly and the big spring lets go

 

Sorry I've got the model no.s written down somewhere. But I'm sure its a 305 model.

[NI Tree]

well it not on my bench my desk (lack a bench at uni:thumbdown:) i got alot cleaning and oiling of a leather harness

[GardenKit]

Glad I'm not the only one who hates them.

 

T he centre pulley is a right pain. The big spring is to user friendly. Took me nearly an hour and LOTS of swearing and bruised hands to get it back on. The pulleys move up and down. Will check if its touching.

 

One bad design on this rode on is no access panel above the pulleys. So with the owners permission going to cut it out and place a panel in bolted down.

 

The belts are new by the way. I'm not really sure what I done but it pulls up a very steep slope easily now. I removed the pulley assembly and added a new plastic bush into the arm, also after putting the belts back on the pedal felt stiffer as if it was actually doing something.

 

Even a simple job like removing the deck was a pain.

 

Just wasn't sure if any shims where needed in the pulleys. And if so how many. His son had replaced the belts before I got there so wasn't sure what he had pulled apart to do it. Really the belts are easy to replace. Rear one is on tensioner idler as you say and the front is held on with a metal guard bolted either side of the engine. So really they are easy to do unless you lose control of the centre pulley assembly and the big spring lets go

 

Sorry I've got the model no.s written down somewhere. But I'm sure its a 305 model.

But did the son use genuine belts?

[Rich2484]

But did the son use genuine belts?

 

Yes because Roy (lom) was moaning about the price of them. Got them from another local (ish) mower shop.

 

I havnt fitted any new belts to the mower, just replaced a bush and reset the belts in place. The front one was coming loose when it shouldn't have like you said.

 

Anyway the mower runs fine now just the scrapping with the pulleys wobbling when its engaged. If one bush was worn it would make sense the other would be aswell. Just didn't check them when I had the assembly apart.

[Rich2484]

Run of t he mill stuff. A mower blade to sharpen and balance.

 

An ms250 coming in. Yes that one.

 

A hedge cutter coming in for sharpen. Done a long reach and double sided already.

 

The ride on is on the list to go and do tomorrow. Doing it the owners garage. He has some nice tools and he is giving them all up. Moving house and his house is going up for sale. He has an old army 110 he has restored that he is going to sell aswell. Might have to check the funds.

 

Got some chain lifting gear from him yesterday. Will put a pic up on gardenkits thread when I take one. I have no use for them but I'm sure someone will.