sthil ts400 chop saw none start

low compression, mworn piston rings, air leak from base gasket, decompressor valve leaking /bent, cylinder base bolt loose, step in crank case, fuel breather tube kinked and blocked fuel filter

[BOXTERS]

If the saw was stripped right down previously(had the crankcase split) there is 2 locating tube dowels which locate both halves of the crank cases if either one or both are missing the cases will not align properly and will result in the issue you are having with the miss alignment of the 2 halves. Crank case pressure test should be .5 bar if it holds this for some time all is good. The "4 stroking" is normal as the ign coil has a rev limiter (electronically controlled internally) this clips the spark at roughly about 9, 800- 10, 000rpm (engine speed) to prevent the blade over speeding and bursting the cutting disc.This gives the sound of 4 stroking, when under load this disappears and the engine will sound like a normal 2 stroke engine...hope this helps in future repairs.

[emclearance]

I bought a Stihl ts400 with a new carburator and top engine part . IT WILL NOT Start, i took off my carburetor on my other ts400, no joy . Even a sniff of easy start, only once in 20 mins, did it fire up for 10 seconds . Then i got to thinking has the New top engine section been assembled correct . As by then i was thinking "Air is leaking " somewhere .
I shall let you know the out come in about 3 weeks .

[giovanni]

How did you remove the flywheel from the crank rod

[bigchief]

its not 4 stroke u will kill it in 4min with just petrol