spudulike

I spend some time on the Arborist site and many of the Yanks are really in to porting and muffler mods etc, one guy took his Stihl 026 as standard and measured the head temperature at idle and WOT, he then ported and muffler modded it and did the same and the temperatures were significantly lower - the general concensus was that the saw was clearing the gasses out faster thus making it run cooler whilst producing more power, revving higher.......and burning more fuel!

Spud

It is possible the spark arrestor in the exhaust is clogged, it could also be an air leak so a pressure check would be worthwhile - normally you get an increase in idle speed that can't be brought down with this though.

Worth checking the impulse hole in the rubber boot lines up with the carb and lines up with the carb.

Check out the carb filters and make sure the fuel tank breather is clear of dirt.

Goodluck

Spud

Spudulike do you have the service manual as a PDF?

Yes - all 16 meg of it!! You can get it here http://www.gardening-tools-direct.co.uk/content/husqwm254_hw1987_1018812-96.pdf

Search and ye will find

Spud

The longest guide bar specified was 36", rule of thumb is divide the cc of the engine by 3 which gives you 26" so a 36" is pushing it - you could try this and a semi or full skip chain to keep the speed up!

Spud

From memory when I worked on mine, you remove the clutch and sprocket, remove the allen bolts that retain the pump and then insert larger bolts in three pre tapped holes and tighten the allen bolts that then push the pump housing outwards as the bolts push against the casing.

The worm drive is a push fit and should come off with a couple of screwdrivers behind it - there is a manufactures tool, like a puller or you could make one.

I do have a service manual for this saw if you want to PM me.

Fab saw by the way.

Spud

A running engine needs spark, compression and fuel - if you have compression 140psi+, and a decent fat spark, then it must be and sounds like fuel, if it is flooding then the needle valve sounds likely - if it is flooding because you are simply pulling the engine over too much with the choke on then that is different!

Spud

Most of the time it is the more easily repaired clutch side seal that goes - up to you if you change both!

Spud

Could be a blockage or leaking impulse circuit stopping a decent flow of fuel at low revs - also worth checking the fuel filter in the top of the carb and don't forget the fuel tank breather.

The breather can be checked by loosening the fuel filler cap to see if it improves matters.

Spud

9 times out of 10 it is the one on the clutch side that goes which is just as well as removing the flywheel can often be a pig!

Spud

Everyone knows the defacto site is Mike Acres -

http://www.acresinternet.com/cscc.nsf/GasbyManufacturer?OpenView

Only problem is the sites been down a couple of days - worth a look though when he is up and running again.

Spud

Agree with the sharp chain but if it is more POWER you want then typical tweaks are: -

Muffler mod - open up the outlet pipe to 3/4 of the exhaust port, take out any spark arrestor and drill more holes in the baffle plate

Open up the inlet and outlet ports - not for the amature

take out the base gasket and seal with liquid gasket - raises the compresion but check the squish

For further info go to the Arboristsite - full of useful info!

If you make any of the changes above, make sure you richen your mixture on the "H" screw by 1/4 turn or tune by ear so you can hear the four-stroking burbling at the top end of the revs

Spud

Put it on the bay - starting price of 99p, start the listing on Thursday evening around 9-10pm on a TEN day listing. Make sure you have many pictures, preferably on well cut grass (sets off the orange paintwork), video of it working on you tube and link the vid, show the compression being checked - you will get top money - I speak from experience!

The listing will end Sunday night - most people will be in and watching, you will have two weekends & ten days for many watchers to gather, great time of the year to get best price but make sure your listing is good with a link to a website selling a new one and state the RRP.

Spud

Say the saw is low on compression, spray the WD40 down the carb, it enters the combustion chamber, seals the piston, raises the compression and bang - it starts!

Spud

If the chain cutters have been damaged, best thing is to put it on a grinder to put it back in good fettle and then use a file again to sharpen once it loses its edge after use.

You can file a damaged chain but it is pretty hard work and difficult to get everything even

Spud

I spend lots of time on Arboristsite and they often say these saws are for sale in South America and I think the saw is genuine but not for sale in Europe or the US.

If you watch any news articles on rain forest clearance you will see some locals using these saws to fell some big old trees - don't know how this guy got them but IMO they are real - Stihl would be none too happy to see them for UK sale!

The copies are usually branded 395XPs and come out of the Zomax factory!

Spud

My money would be on a blocked tank vent or low compression - compression falls as the saw gets hot and if it is borderline can stop a hot saw starting.

You can check a blocked tank vent by running the saw with a loose petrol cap.

Crank seals are unlikely as usually the saw races at idle and will need an over rich setting on the L screw to compensate - that is if it doesn't sieze in the early stages.

Spud