Husqvarna 450 won't start

[Gentleman]

We have this saw that a customer brought in. 6 months old won't start. We have checked everything on this saw and can't figure it out.
Compression, vacuum/ pressure test, fuel line, intake manifold, impulse, spark all good. Just put a new carb on it and still nothing.
Anyone seen this before?

 

[huskyboy]

Will it pop with fuel down carb throat? New plug?

 

[wcorey]

Sheared flywheel key?

 

[merc_man]

Is muffler plugged?
Any scoring on cylinder?

Sent from my SM-J320W8 using Tapatalk

 

[Onan18]

Sheared flywheel key?

THIS!!! ^^^

Also seen coils show good spark, but will not crank or run correctly. Did you put a new fuel filter in?

 

[Simondo]

Wet plug?? ...dry plug?? ...no pop at all or a pop and then still wont run??

 

[Chainsaw Jim]

Usually when I come across this it's either something wrong with the air filter or a broken torsion spring inside the spark plug boot. Then there's the bad ignition system which is a little less common in my experience.

 

[Stump Shot]

We have this saw that a customer brought in. 6 months old won't start. We have checked everything on this saw and can't figure it out.
Compression, vacuum/ pressure test, fuel line, intake manifold, impulse, spark all good. Just put a new carb on it and still nothing.
Anyone seen this before?

Yes, a component in the module inside the coil gives out and the spark you see is not powerful enough to spark under compression and the engine will not run.

 

[psuiewalsh]

Inline spark check should tell you if it's hot enough

 

[J_M____]

I’ll vote for flywheel has spun and is firing with incorrect timing

 

[Gentleman]

Will it pop with fuel down carb throat? New plug?

Yes new plug and you can barely hear a pop.

 

[Gentleman]

Sheared flywheel key?

The last thing I did was pull the flywheel and checked the key. It is good.

 

[Gentleman]

Is muffler plugged?
Any scoring on cylinder?

Sent from my SM-J320W8 using Tapatalk

I pulled the muffler to do the leakdown test and the piston looked good.

 

[Gentleman]

Wet plug?? ...dry plug?? ...no pop at all or a pop and then still wont run??

Yes plug was wet when I pulled it.

 

[Gentleman]

Also seen coils show good spark, but will not crank or run correctly. Did you put a new fuel filter in?

We first thought the coil so we swapped one off a new saw just to try.

Did not change the fuel filter. I'll try it. I hope it is something that simple.

 

[Terry Syd]

My modified 450 is the most reliable starter of the bunch. Three pulls with the choke, maybe four, and the engine comes to life.

I had a problem with the fuel primer when I first got it. It used to flood the engine. The pressure in the tank would over fuel the wet side of the carb. I ended up blocking it off. No more problems after that.

 

[Veljko]

I have problem like that.They have put fuel line in wrong order on primer.

 

[psuiewalsh]

How wet? Try holding wide open throttle while cranking?

 

[merc_man]

Pull plug and dry out.with compressed air.

Sent from my SM-J320W8 using Tapatalk

 

[backhoelover]

Flywheel magnets!!!Had it happen on a 455 one time had me straching my head