I have a couple of these tiger shark engines from Kangke and they both run great. Never had a dead stick yet. I have a tiger shark 46 & 52 and I was thinking about getting AJ to build me a diesel head for one of these. I just got my Magnum 75xl running with one of AJ's diesel heads and with a 15x6 wood Zinger prop I am getting 9000 RPM at top end and 2000 rpm at idle. I think you might be able to get a little more out of your Tiger Shark 91. I find these TS engines to be very powerful. Let us know how it runs when you can.

Thanks