Stihl 024 AVS with strange symptoms

[Mad Professor]

Yes, I started with a seal puller, which got the non-flywheel side out, but instantly broke on the flywheel side, so I popped it out with a screwdriver, which was difficult. I'd seen it done on youtube, but I'm sure I scored the inside somehow. I can't really see (or get a photo) until I get this seal out. Aerobic sealer might be the way to go. I will figure out how to properly remove and then get a new seal. Good to know that the cylinder is looking ok but I'll probably not replace the piston until I'm sure the seal problem is solvable.

Spend some time cleaning up the cylinder before you even think about getting a piston. Post some good pictures of the cleaned up plating. If the plating is all there you need to remove all the aluminum transfer.

As Bob said a scratch where the seal seats in the case can get fixed with some good sealer. It would be worse if you scratched the crank.

I've even heard of people fixing that type of leak, by putting the saw under vacuum and applying sealer to the location of the leak, so it pulls the sealer in. Not as good as a proper fix.

 

[ktpnw]

Spend some time cleaning up the cylinder before you even think about getting a piston. Post some good pictures of the cleaned up plating. If the plating is all there you need to remove all the aluminum transfer.

As Bob said a scratch where the seal seats in the case can get fixed with some good sealer. It would be worse if you scratched the crank.

I've even heard of people fixing that type of leak, by putting the saw under vacuum and applying sealer to the location of the leak, so it pulls the sealer in. Not as good as a proper fix.

Great info, thanks. What’s the best way to clean off the aluminum, just a mild scrubby pad and elbow grease? What kind of sealer would be recommended?

 

[ktpnw]

Ok big progress has been made. Gasket maker sealed up the leak great, I actually ended up doing as Mad Professor noted and sucked the gasket maker in with a vacuum. Figured I'd give it a shot and it works great, if it fails I will pull the seal and do it the right way. After letting it cure overnight it passed a pressure test, held both vacuum and pressure (10PSI) for 30 seconds without any movement of the needle.

I also was reviewing the carb diagram and noticed a crucial thing, I had the metering diaphragm and gasket switched (installed in the wrong order). I am positive I put it in the same as I took it out, so the previous owner must have switched them. Good lesson to not trust that things are put together correctly. But unsurprisingly, putting those in the right order also made it run much better. Doesn't smoke nearly as much now, so I think that was the culprit of that issue.

Now to get a new piston and clean up the cylinder and I should be back in business. Thanks again to everyone here for the knowledgeable help, it's really very much appreciated. I will pay it forward how I can.