Hey xtraflyr,

I have the same brison 4.2 that I bought in 1995. I just sent it back to Brison for a check up. They are also updating the mechanical advance and something with the nylon ring. It will be interesting to see if it runs any different. The motor always ran fine, but it has been sitting for a couple of years. I have always used the zinger 22x10 prop. If I remember right it tachs 6700 rpm. This is with the very restrictive slimline pitts muffler. I'm also at about 4400ft. Brison said with the 22x10 prop and open exhaust they have readings of 7300 rpm. I run all my Brison motors with a 80 to 1 ratio using synthetic oil. Enjoy!