diagnosis

[openspaceman]

Fair enough but personally i would not run a saw for 30 seconds on old fuel .

 

I'll concede that to you and Stubby, even the husqvarna leaflet cites it as a cause for seizing. so best advice must be to change it for new fuel.

[openspaceman]

Been asked to list this PDF by another member:001_tongue:

 

Thanks spud, that must be one of the attachments from the chainsaw repair forum cut4fun mentioned??

 

re your previous post, this saw came to me after the fitters so was already in bits with the plug missing.

 

As the rings were stuck and only light scoring on the exhaust side I'm tending to think over revving coupled with lean mix .

 

re Gardenkit's test, I do remember seizing a newish saw by using neat fuel, it was in the days of 4 star before unleaded was available and yes it ran for more than one tank before failing, at the time I put it down to the lead acting as a lubricant.

[GardenKit]

I thought you could kill a 2 stroke in seconds/minutes without oil in the fuel. Seems hard to believe!!

I thought just the same Rich, and still tell my customers the same now when telling them how to fuel their machine.

[GardenKit]

I remember your test, very interesting although on a saw, you are pulling another circa 3000rpm+ and is under a lot more load in a big cut so may be different - you got any saws you want to test with sraight fuel?

 

All interesting stuff though!

I agree Steve, but after all the little 22cc strimmer was running flat out, with no respite for that time, but not under load. Still amazing though.

 

But it does prove the need to identify the cause of seizure. There are some people who would just whack on a Pot and Piston.

 

This may be fine in the case of a lean seize where we know the correct mix has been used (as long as the cause of the lean running is fixed). The lower end should be fine as it has always had lube.

 

But in the case of a 'straight fuel' seize, the crank and bearings have been denied oil and so will have significant wear. Sticking a P&P on this may well be a false economy as the lower end is likely to fail soon after.

 

I personally will never repair a 'straight fuel' seize without doing the bottom end too, but this is seldom economic.

[Richard 1234]

I thought just the same Rich, and still tell my customers the same now when telling them how to fuel their machine.

 

 

I'm going to try and get some aspen for next week as I have a month of hedge cutting starting and I want to try this stuff and see the difference for myself.

Cutting hedges always seems to blow exhaust vapour straight into my face!!

[GardenKit]

I'm going to try and get some aspen for next week as I have a month of hedge cutting starting and I want to try this stuff and see the difference for myself.

Cutting hedges always seems to blow exhaust vapour straight into my face!!

Good Man!

You will appreciate the difference.

Do you have a local supply? If not we can deliver direct.

[Richard 1234]

Not sure I think so but in London for the week so was hoping to pick some up here or on way back to Lincoln will try aspen website I suppose to find dealer?

[spudulike]

I agree Steve, but after all the little 22cc strimmer was running flat out, with no respite for that time, but not under load. Still amazing though.

 

But it does prove the need to identify the cause of seizure. There are some people who would just whack on a Pot and Piston.

 

This may be fine in the case of a lean seize where we know the correct mix has been used (as long as the cause of the lean running is fixed). The lower end should be fine as it has always had lube.

 

But in the case of a 'straight fuel' seize, the crank and bearings have been denied oil and so will have significant wear. Sticking a P&P on this may well be a false economy as the lower end is likely to fail soon after.

 

I personally will never repair a 'straight fuel' seize without doing the bottom end too, but this is seldom economic.

 

Not wishing to be controversial or lambasting my mate Barrie, we all have different ways of working and ways of doing business.........I have done a significant amount of repairs to seized machines with only one ever coming back and believe that this was just a case of the saw bedding in a bit fast and over-revving and not being picked up by the operator. Even this has now been fixed again!

 

The bottom ends tend to take a fair amount of abuse due to the nature and size of the bearings but do check them for play and smoothness before reassembling.

 

I have had one machine that actually bent its rod when it seized but even managed to straighten that using some VERY unconventional methods and it ran OK afterwards.

 

Some saws deposit a lot of aluminium if they still run poorly after seizing. These can be touch and go but as long as the mains are flushed and show no sign of being "catchy" then it is worth a punt IMO.

 

The bottom line on this sort of repair is to Pressure and Vac test all machines that have failed ensuring the crank seals, impulse line, manifold and ALL sealing surfaces are airtight. I also check the fuel line and carb ensuring it is clean, in good condition and then tach the machine so the saw is known to be good - I guess this is why I have a higher level of success than many less stringent techs.

 

Each man to his own, I know what works for the guys that send their machines to me and think the result is proof that it works.

 

Sorry Barrie, just my own opinion:blushing:

[agg221]

Not sure I think so but in London for the week so was hoping to pick some up here or on way back to Lincoln will try aspen website I suppose to find dealer?

 

Depends which route you are taking back to Lincoln, but if it's up the M11 then Duxford Hire & Supply is less than 5mins off route.

 

Alec

[Richard 1234]

Depends which route you are taking back to Lincoln, but if it's up the M11 then Duxford Hire & Supply is less than 5mins off route.

 

 

 

Alec

 

 

Thanks Alec but we are stopping in Milton Keynes to stay with family on way back donut will be M1 -A46 home!