So problem #2 above, of the throttle slowing down on its own when you remove your hand from the tiller, has been solved. Racer's suggestion of needing part # 174741 appeared to be the best approach. I did not want to cut into the material covering my throttle cable under the tiller, so as to attach a clamp, as mentioned here and in Leeroy's Rambling, because my covering material is more of thick rubber winding tape wrapped along its length and once I cut it, to get at the throttle cable, I worried it would come fully unwrapped and I would have to cover it all with something else. The only issue I had with part #174741 was where it went precisely and what it actually did. I was worried that it was a sort of lock that one might tighten for trolling. My problem was stabilizing the throttle at higher speeds and one cannot "lock" a tiller at high speed because the ability to quickly unlock a throttle is effectively your brakes on a boat and the ability to quickly slow down, I think most of us will agree, is fairly necessary for safety on a boat. So I decided to see if I could replicate part #174741 (throttle friction control) with a simple hose clamp as shown in the picture below. It worked perfectly. Once tightened, one maintains full control of the twist grip/throttle but it does create enough friction to stop the twist grip/throttle from slowing down on its own, at all throttle speeds.
That problems was actually quite annoying. Thank you everyone for your help. I just wanted to post an easy fix for anyone who finds themselves with this problem and it also shows precisely where part #174741 would go and how it would go if you prefer the more BRP approved solution.
