Stihl 051AV

[bolla]

Hi I have a stihl 051Av it has been sat on the shelf with fuel and oil for a few years.

The other day I tried to start it it felt like it had alot of compression, could just about pull the starter any how the saw started I revved it a bit it seemed fine ,as i was at home in the garden did not want to run the saw for long.

Took the saw to work filled with fuel and oil tried to start it was locked solid, removed spark plug pulled starter it turned over nice and what looks like chain oil came out the spark plug hole

left the saw for a while put plug in it popped and produced a bit of smoke but then locked up again removed plug this time am getting fuel mix alot less oil out the plug hole.

I guess the fuel could be getting in the crankcase if the float is stuck open but what about the chain oil

Are the fuel and oil tanks on the side of the crank seals 

Any ideas

 

The last time I used the saw it used a lot of petrol and with a 36" bar was not oilling enough, I think 36" bar is the biggest you can run on the 51 so it should oil

but if petrol and oil and leaking into each other it may be the problem the chain oil is diluted and not working

 

Thanks for any idea

still looking for an exhaust for an 056 if any one has

[Stubby]

I would never try and start a saw that had old fuel in , a few weeks is old let alone a few years for fear of the damage that can happen .

[lurkalot]

Possible crankcase gasket failure, that would let the oil from the oil tank to get straight into the crankcase http://www.motoculture-jean.fr/upload/pdf/050_051.pdf

[spudulike]

If the crankcase is filling with fuel mix, the needle valve or spring may have failed or the metering diaphragm has gone hard and is holding the needle open. 

The chain oil is probably the gasket and a pressure, vac check will prove that. 

[Rough Hewn]

Yeah mate, oil tank is a b***ch.

if the gasket has gone, oil will leak into crank case.

the pipe leading to the oil pump from the tank may be partially blocked also?

big nasty job.

[peatff]

Drain the chain oil out of it just to see if it will run longer without any, a couple of minutes not cutting will not hurt. You'll most likely have to do something with the carb before it will run properly anyway.

Edited August 9, 2017 by peatff
punctuation.

[Rough Hewn]

After spending lots of time, effort and money on repairing 051,056s and an 075. (Blew the oil reservoir/crank seals.)

Finally got them fixed up, all oem.

great saws.

then bought an 880 and 661 new.

after a few weeks I could never go back to using dinosaws.

I loved my dinosaws but they got sold. 

Got a brand new oem decompression valve you can have if you need one?