Husqvarna 440 with stripped spark plug - worth rebuilding?

[David Ellis]

Yup, 4 of 5 mm hex for all of my Husqvarna saws (slightly older) for the muffler screws.

 

[lone wolf]

A new cylinder for bad threads?
Sparkplug threads are a common repair in the shop. I have used regular Helicoils and the sleeve type. Use grease on the tap to catch shavings and clean out the cylinder when done.

Do you pressure test after the repair?

 

[flymo]

5mm Allen it is! Thanks folks! And also good news is that by shining a flashlight through the plug hole, I can see the entire top of the piston via the exhaust port, so I should be able to find any stray chips.

 

[stihltech]

Do you pressure test after the repair?

I do not. It is important to rethread straight and that the gasket on the plug can seal to the cylinder. No repair threads above to interfere.

 

[lone wolf]

I do not. It is important to rethread straight and that the gasket on the plug can seal to the cylinder. No repair threads above to interfere.

I have found that some of them leak.

 

[J D]

I have found that some of them leak.

I found that with one i didn't get quite right... made myself a little reaming tool that fit snugly in the hole & evenly machined down the top of the insert/cylinder so everything was flush & at 90° to the plug hole

 

[Chevboy0167]

https://www.vibra-tite.com/threadlo...t-lock-extreme-high-temperature-threadlocker/