Hey Dave;

I have some general interest questions:

1) On my 63S, the green coating on the disc valve is almost totally gone. How much does this affect engine performance ?
Should it be replaced ?

2) The 63S beats the old 63 by about 1000 rpm on an 11x7 prop (my examples). How much of that is due to the green stuff ?


Thanks;

The "green stuff" is for corrosion resistance only. NO HP gain. The 63S is runs stronger due to the "linerless" cylinder which dissipates heat more readily.