Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: artsamm on October 12, 2013, 09:14:06 am

Title: MS 460 No Start
Post by: artsamm on October 12, 2013, 09:14:06 am

Good Morning, have a MS 460 that will not start. After about 20 minutes of use it stopped. Pulled oin cord and would not pull. First thought was. "This is not good"
Pulled recoil assembly off and it must have been bound up, crankshaft turned. Put it back together, and it would turn over but would not start. Does not even "hit" like it does right before you would drop it to 1/2 choke.
Did some further checks:
Plug: clean, and .020 gap (good according to spec)
air filter: clean (tried starting without air filter, no go)
Gas filter: clean
gas: Not old,  and do have a small odor of fuel when cranking over, does not seem enough of an odor to be flooded. Besides if flooding was an issue, should clear out over time.
ignition: has spark at plug when pulling cord with  switch on; none when switch off.
compression PSI: 75 psi at first pull, 100-110, after 4 consecutive pulls (appears OK, although not certain what spec is on a small 2 stroke). Used 2 different gages, same result.
Removed compression release to make sure that was not stuck open or damaged;  that looks OK.
Tried starting with compression release in both positions (pushed in, puled out), No go. Been trying to start saw on ground with foot on lower part of rear handle.
Any advice? Thanks alot everyone!

Title: Re: MS 460 No Start
Post by: Cut4fun . on October 12, 2013, 09:28:14 am

Pull muffler off and look at piston and rings.  PSI sounds like this.

 Check fuel line, fuel filter, impulse line, tank vent also while you are at it.  Good looking over basically.

Title: Re: MS 460 No Start
Post by: artsamm on October 12, 2013, 09:42:21 am

Not certain what the impulse line is. Tank vent, I believe that is top of tank near fuel cap? I work on trucks, not small 2 strokes (2 srtoke Detroit diesel, I know better) Thanks for the help.

Title: Re: MS 460 No Start
Post by: Cut4fun . on October 12, 2013, 09:46:38 am

Pull the muffler off first for a look at the piston and rings first hand. 

Then I will post a pic of impulse later.  Going to a chainsaw gtg.   

Need to figure why it toasted topend if it is scored.

Title: Re: MS 460 No Start
Post by: artsamm on October 12, 2013, 09:49:45 am

Thanks alot!

Title: Re: MS 460 No Start
Post by: Cut4fun . on October 12, 2013, 09:50:19 am

That was 2 easy.  Here is a 046 460 thread of rebuild I just did.

You can see impulse line between tank running to cylinder.  It is off in pic, not attached to cylinder in one I seen.  http://chainsawrepair.createaforum.com/stihl/stihl-046-460/

Title: Re: MS 460 No Start
Post by: Adirondackstihl on October 14, 2013, 08:43:35 am

Hmmm......nobody mentioned flywheel key  ;)