Ok I have an Hanger 9 P-51 PTS and loving it. Went flying on Sunday and noticed an excessive amount of oil on the plane after flight. While refuling I noticed the muffler was lose and tighten it. But now I notice that there is still a small amount of liquid leaking from where the muffler goes together in the middle of it. Is this a problem and do I have to get a new gasket for the middle of the muffler? And it is not leaking from where it is mounted on the engine. Please let me know.

first make sure all the bolts are tight there should be one that runs through the muffler also .if its really bugging ya and still leaking try a small amount of RTV silicone a local auto parts store item make sure it is the kind for aluminum and make sure the muffler is clean when you use it. denatured alcohol works great to get most all the oil off so the silicone sticks properly , don't use too much and you will be set.

The High temp RTV works great in the muffler seam. Make sure you tighten the screw first then just use the nut as a lock nut.

I have the same engine in a tower trainer. With the same problem. Must be common to the evo pts engine. I put a one piece Macs muffler on mine, just for the fact of it not seperating and leaking. It also gives a slight power/rpm increase, not that I really need it on a trainer. I am not sure if it will fit on the p51 though due to the cowl and the slant of the engine.

Layne

just another tip,once you tighten the muffler through screw add some fingernail polish to the exposed threads that will help some keeping the screw tight.most of the guys at the field use nylon straps around the mufflers in case the through bolt comes loose and lose half of the muffler,i have seen many mufflers fall apart and a screw is cheaper than a new muffler.