MS 291 gas cap leaking...

[stillhunter]

I've had it for years and it's been great. I don't know if the O ring needs replaced, it looks good but could it be swollen?. I also notice the cap lock seems to be stuck and hard to shut.

 

[thompsoncustom]

I've had my oring get dry enough it doesn't move and seal so gas is pouring out. I take the oring out and grease it than put it back on and it always seems to fix it.

 

[irhunter]

New OEM caps are 9 bucks. The o-ring is something less than that at the dealer. Or, next to nothing at a plumbing supply place. All you need is a Buna-N o-ring.

Roy

 

[user 74409]

With the cap being hard to close my vote is to spring for new cap. I was in similar boat with leaking MS250 oil cap. I bought new o-ring only to have cap mechanism plastic break the next day. I bought 2 new caps (fuel and oil) for $18.44 + $4.30 shipping and my problems were solved.

 

[aledub]

Clean the threads and replace the o-ring with something made of oil/fuel resistant like Buna. Sometimes I get a leak on the oil cap and have found some sawdust on either the threads or the actual o-ring itself. It usually solves the issue for me and if that fails a new cap is in order. I keep an entire kit of o-rings in both metric and imperial plus I have a kit that I can make my own custom if needed.

 

[stihltech]

The cap itself has swelled from fuel. Replace it.