What's on your bench today?

[peatff]

thats what I thought, but he said he had been using it for an hour on the day it siezed!

 

Of course, when I sold it originally it was filled with Aspen. This must have protected it long after it was used up. Marvellous stuff!

 

It must have gradually diluted the original mix to a point where it was no longer viable 10,000:1 mix ? Just waft the bottle past it every third fill it should be grand.

[spudulike]

thats what I thought, but he said he had been using it for an hour on the day it siezed!

 

Of course, when I sold it originally it was filled with Aspen. This must have protected it long after it was used up. Marvellous stuff!

 

Nice slightly chilled with ice and a slice eh Barrie:001_rolleyes: Every workshop should have a bottle in the fridge!

[GardenKit]

Right, so this issue of running without oil got me thinking. I have always assumed a failure would occur within about 10 minutes. It is one of those things I assumed but actually have no real knowledge of.

 

So today I ran a test. I used an old, but perfectly good, Partner strummer. Drained out the 2 stroke Aspen an refilled with 4 stroke Aspen (no oil)

 

Started it and taped the throttle up to full revs and stuck it outside. i expected it to fail in 10 minutes, but it ran fine until it stopped afar a massive 45 minutes.

 

I expected to find it seized, but it had only run out of fuel, so I refilled the tank.

 

It started again, but not easily, and ran for a further 13 minutes before gently dying.

 

Once again i expected it to be seized, but it pulled over freely. It would not start though.

 

So I pulled the pot off. The piston was scored, but hardly so. The bore was a little scored also, but not much.

 

So 58 minutes at full revs on neat fuel before it stopped with hardly any damage. So how the hell do pistons get scored as badly as we usually see? (I do not really expect answers!)

 

 

 

 

 

[spudulike]

Right, so this issue of running without oil got me thinking. I have always assumed a failure would occur within about 10 minutes. It is one of those things I assumed but actually have no real knowledge of.

 

So today I ran a test. I used an old, but perfectly good, Partner strummer. Drained out the 2 stroke Aspen an refilled with 4 stroke Aspen (no oil)

 

Started it and taped the throttle up to full revs and stuck it outside. i expected it to fail in 10 minutes, but it ran fine until it stopped afar a massive 45 minutes.

 

I expected to find it seized, but it had only run out of fuel, so I refilled the tank.

 

It started again, but not easily, and ran for a further 13 minutes before gently dying.

 

Once again i expected it to be seized, but it pulled over freely. It would not start though.

 

So I pulled the pot off. The piston was scored, but hardly so. The bore was a little scored also, but not much.

 

So 58 minutes at full revs on neat fuel before it stopped with hardly any damage. So how the hell do pistons get scored as badly as we usually see? (I do not really expect answers!)

 

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Very interesting - have you got rid of your backlog of work:001_rolleyes: Me to:thumbup:

[elliott EGD]

That is interesteng and quite impressive to beaing a domestic model . Just a thought it may not have scord as much as it was at full revs constant maby as slower revs or intemitent revs would alow the piston and cylinder to bond slightly .

[wisecobandit]

Theoretically speaking I guess no load on the strimmer engine would equate for a richer mixure equalling cooler running Barry which may extend running time before seizure?

 

Its an interesting topic as like you say we all assume it would only be a short run time on neat fuel.

 

Reminds me of an old guy I used to know that never used to mix his fuel so meticulously as most of us. He would have a full fuel can, unscrew the 2 stroke oil lid and just fill the lid up with oil and throw it in the can yet never seemed to have an issue with any seizures even tho it was prob nearer a mix of 80/1! I am talking 20 years ago so maybe machines wherent pushed to there limits tunability wise as today and fuel had less ethanol etc which may have helped.

[Eddy_t]

That's using aspen Barrie, I have stated before, I believe aspen runs cooler than normal petrol due to less volatile hydrocarbons in the mix

 

 

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[GardenKit]

I really do not think there is much difference in the burn temp. Sure, it is cooler rather than hotter, but not much.

 

I only used Aspen as I no longer keep any petrol on the premises. Horrible smelly stuff:biggrin:

[bobh]

A mate has just bought a husky 372 and got me to take a look at it for him, the saw seems in reasonable nick externally but I'm suspicious about the cylinder, its just too clean, looks as if its a recent replacement.

If its an OEM part what markings would it have on it, (makers names etc) as this seems to have none.

Also its holding revs a little bit after throttle release so I guessing an airleak as well.

 

Sent from my Nexus 7 using Arbtalk mobile app

[spudulike]

A mate has just bought a husky 372 and got me to take a look at it for him, the saw seems in reasonable nick externally but I'm suspicious about the cylinder, its just too clean, looks as if its a recent replacement.

If its an OEM part what markings would it have on it, (makers names etc) as this seems to have none.

Also its holding revs a little bit after throttle release so I guessing an airleak as well.

 

Sent from my Nexus 7 using Arbtalk mobile app

 

The base or the transfer bulge will bear the manufacturer name "Mahle" and on it and the very top of the cylinder by the plug hole, the flat will have "A" or "B" engraved on it !