Loose heli-coiled plug

[Stihlmar]

Any advice out there for fixing a heli-coiled spark plug that's loose? Plug is tight in the coil but helicoil is loose in the cylinder. Was going to try and vac test the saw but even before tear down was done. Turned it over and heard it hissing. I would assume that would cause it to run erratic and not hold a tune?

How many 064 cylinders do you guys have laying around?

 

[Ozhoo]

Loctite would be the first thing to try. As for effecting the tune, no it does not.

 

[schmauster]

It will make it run weird if it has a loose plug, ive chased 'tuning issues' to find a plug that was loose. Erattic idling and everything. Once you get it tight things should smooth out. A little loctite or maybe some JB weld

 

[Van462]

Loctite 294 is a high temp wicking grade. Bad part about loctite it will be creating an insulator around your ground. I would think there would be sufficient metal to metal to provide a good ground but who knows.

 

[Thommo]

It might be worth trying a copper washer under the spark plug. The plug should seal on the flat part that the washer seats on and not the thread.

 

[Little Al]

If IRC Timeserts are larger dia than Helicoils you could try & see if the timesert will screw into the slack helicoil threaded hole? or tap out for the Timesert I much prefer over the Helicoil as it's a solid insert, I have tried Locktite & found it to be only a short term fix

 

[LondonNeil]

I recently had success sealing a plug in a similar but not identical situation with a 1.5mm thick copper washer. Photos of my problem on my 'new to me 038 thread'. My saw was running but had been set very very rich, it's better now.

 

[pioneerguy600]

As stated above ^^^ have a Timesert installed in place of that Helicoil. The ones I have fixed are still running many years after installing the inserts.

 

[earlthegoat2]

If you want to use thread locker for a short term diagnostic on the saw then go ahead and do that. I do not think the Loctite will hold it forever though.

There is also a solid one piece helicoil brand insert that could be tried for quite a bit less expensive than a genuine TimeSert.

Only problem is that I think by installing the Helicoil it may have jeopardized the linstallation of said solid insert. Maybe still something worth taking a look at. Solid inserts also need to be installed with Loctite for retention and sealing purposes.

TimeSerts are one of the very best spark plug thread fixing devices out there and they have a long history of success behind them. Spiral thread helicoils do not.

 

[Little Al]

If you want to use thread locker for a short term diagnostic on the saw then go ahead and do that. I do not think the Loctite will hold it forever though.

There is also a solid one piece helicoil brand insert that could be tried for quite a bit less expensive than a genuine TimeSert.

Only problem is that I think by installing the Helicoil it may have jeopardized the linstallation of said solid insert. Maybe still something worth taking a look at. Solid inserts also need to be installed with Loctite for retention and sealing purposes.

TimeSerts are one of the very best spark plug thread fixing devices out there and they have a long history of success behind them. Spiral thread helicoils do not.

The solid Helicoils I have had dealings with still had the sharp diamond shaped thread profile if the female thread in the head is a bit dodgy & the plug is a bit heavy handed in the tightening I have had the helicoil thread split they seem lightly constucted in comparison to the Timesert as said TS's are along lasting fix

 

[Deleted member 149229]

A loose heli-coil insert will never be trustworthy, installed them for many years and if he tapped hole isn't right then neither is the heli-coil.

 

[backhoelover]

http://www.ebay.com/itm/HELICOIL-M1...358785&hash=item2ef39c979d:g:oQgAAOSwmrlUzrrS

 

[earlthegoat2]

http://www.ebay.com/itm/HELICOIL-M1...358785&hash=item2ef39c979d:g:oQgAAOSwmrlUzrrS

yes, that is the one I was referring to above. It is not as thick as the timesert but I have had luck with it when repairing original threads. Im not sure this will work in the OPs situation though since it has already been drilled out and tapped for the helicoil.