Pressure in the fuel tank

[Yournamehere]

Could a vacuum give the impression of pressure?

That when you take the cap off, air rushes in and fuel splurges out?

A bit like blowing the dust out of a glass and getting a face-full of dust.

Just a thought.

[peatff]

Could a vacuum give the impression of pressure?

That when you take the cap off, air rushes in and fuel splurges out?

A bit like blowing the dust out of a glass and getting a face-full of dust.

Just a thought.

 

It might do but if you have a vacuum in your tank the fuel will stop flowing and the saw will cut out.

[Yournamehere]

It might do but if you have a vacuum in your tank the fuel will stop flowing and the saw will cut out.

 

check.

next.

[Will Heal]

It might do but if you have a vacuum in your tank the fuel will stop flowing and the saw will cut out.

 

 

No it's not a vacuum none of theses symptoms.

 

Any way the saw can't be too poorly, I think it's breeding

Bought a runner on eBay for spares today

[traktorz]

Having had a pair of Jonsered 535, albeit not the same model as this 520, I guess they share some similarities.

 

I remember the tank ventilation is a bit complex with filter and hoses. This filter might be stuck.

 

When 535 was introduced, one new feature was the air gap isolation of the tank, that should avoid fuel vapour problems.

 

Maybe less fuel vapour problems with Aspen alkylat fuel?

 

So, try use Aspen and re- or triple-check the tank ventilation!

[harrythecat178]

We had a MS200T arrive with a similar issue, it was down to blocked cooling fins, the saw had been having cooking oil rather than chain oil and hence had baked a sawdust cake inbetween fins, We had to use a hacksaw blade to cut fins clean

[GardenKit]

Having had a pair of Jonsered 535, albeit not the same model as this 520, I guess they share some similarities.

 

I remember the tank ventilation is a bit complex with filter and hoses. This filter might be stuck.

 

When 535 was introduced, one new feature was the air gap isolation of the tank, that should avoid fuel vapour problems.

 

Maybe less fuel vapour problems with Aspen alkylat fuel?

 

So, try use Aspen and re- or triple-check the tank ventilation!

For some reason I seem to like the Aspen idea:thumbup1:

 

Although Aspen may well improve the issue due to its slightly lower vapour pressure, I feel it would be as well to identify the cause first and effect a cure.

 

The saw should run fine on petrol, it always used to and has only changed on the last fill up. I really would just take the simple action of changing the fuel first. There really are problems with bad batches of petrol, even when 'fresh'. I know of one machine at least, that just would not start on a fresh fill of fuel, simply changing the fuel to some from a different garage cured it.

 

Cure it first, then run on Aspen:001_smile: