560xp not starting, spark OK

[adw]

Sorry Stubby there is no solenoid as such, the auto tune unit on the side of the carb is not available as a spare , so it would be a new carb, unfortunately new carbs come with no firmware on them, so it would have to go to somebody with access to CST ( common service tool ) as for the mods on the very early 560, this was to take the breather hose away from the air folter elbow, the problem was fuel gas being sent into the elbow causing issues, the fuel hose was also shortened to stop kinking under the carb floor, the fuel hose has been altered again to take it further away from heat transfer from the cylinder, slots in the top covers were added to aid cooling,  there have been numerous changes to the main bearing cage material, cages breaking up has been on going, you only know its gone as you get a strange vibration and some poor running, it then rips the crank seal and they no longer run, maybe the problem, there has also been issues with the air filters allowing dirt through which has not helped the cage situation, black frame filter 80 micron, yellow frame filter 44 micron and orange frame 25 micron, the latest 560 now has a higher top cover and the filter and elbow from the 550 mark 11, it would be very unusual for the auto tune unit to loose its firmware, the ring peg in the piston has been moved a few times doe to heat allowing it to come out and cause a seizure, the later crankcase now has the same main bearing on the flywheel side as the drive side and a cover washer to protect from dust, also yey another cage material from SKF. THERES NO STOPPING ME ONCE I START SORRY.

[spudulike]

Basically the manufacturers are struggling to make their machines meet the demands of the US EPA and are in a state of flux.

Damn...I should have been in PR (Public Relations)!!!!!!

[Paddy1000111]

I didn't even think about blown crankcase seals/vac testing the crankcase. I suppose it would still fire over with some fuel dribbled in too....

[adw]

 Emissions are driving everything in this industry now days, and the push to go fully battery is coming at a pace, time we hung up our tools and accept the two stoke is a dying breed. But still looking forward to the 592

[mirecc]

Haven't pressure tested the crankcase but i am positive that no fuel is coming through carb into cylinder. Maybe it is worth to disassemble it and try to blow nozzle and passageways, check strainer etc. Maybe there's just something clogged up somewhere? It's earlier model 560xp, fuel hose is defo older style, connected to carb's intake under the air filter. Not sure about firmware updates.

[adw]

I am always wary when a saw is running fine one day but will not start the next, It usually means it has suffered a partial seizure, this will also account for why it's not pulling fuel through, you really need to do the easy stuff before wasting time, a quick compression test, or at least pull the muffler off and check the exhaust face of the piston, if you have already done this then the next step is a pressure/vac test

[Khriss]

19 hours ago, adw said:

 Emissions are driving everything in this industry now days, and the push to go fully battery is coming at a pace, time we hung up our tools and accept the two stoke is a dying breed. But still looking forward to the 592

Sod that. Will just rebuild older Huzqys. K

[Paddy1000111]

can you hold the saw up by the starter? i.e. hold the starter handle and let the saw go, does it drop and turn over or hold up? Usually a pretty fool proof "rough" compression guide. 

[spudulike]

The poor mans compression gauge!!!

[adw]

Heaven help us, you may as well kick it down the road and see if it bounces.