So I lag, but yesterday I finally got around to trying out the pump swap.
First off it was cold, I got there late in the day, and I had some technical issues, but I did get some pump time. I forgot to tighten some bolts which led to me flooding my engine compartment in a matter of minutes. Fixed the problem and ended up with a dead battery. After a jump and then borrowing a battery I finally got to beat on the ski a little.
Wow the results were good. Even without the proper Impeller (Skat straight 16), tuning being off (temp is like 20-30 degrees colder), and my engine needs freshened up, It hooked up much better. Pulled a little harder on bottom. The response at mid rpm when I opened it up was significantly crisper. I actually pulled something in my left shoulder from opening it up at mid rpm and getting yanked. Handling seemed good, I didn't really hit any hard carves or turning as it was cold and I'm a *****. It did seem more stable, slightly more responsive, and smoother in the steering though.
I did have one small hick up which could be a combination of tuning and impeller size. I would open it up at idle and run all the way to top speed. About mid way through I would get a small "burst" of cavitation and then it would immediately yank hard. Nothing horrible in anyway, it really felt like the engine jumped in power at that point in the rpms, and it took the pump a split second to pull some extra water. As i said it was a split second and the ski basically hopped and then pulled hard. Don't know if that makes sense.
I did also get to play with the trim a little. Wow! I had it set up for nose down at first and it was a bit more stable at high speed. I ended up adjusting it for maximum trim nose up and it made a huge difference. My 130 lbs had to struggle to get the nose out of the water with the Pro-Tec plate before. With the trim up I just stood at the back and the nose would ride high, blip the throttle and I was vertical without even pulling or doing anything other than holding on. One down side, the cheapy knob I bought as a temp adjuster broke off during the last ride, no big deal as I just had it on their to try it out before I made a more solid one.
Basically top end was the same, bottom end and mid were much more responsive and overall pull was harder and smoother. This was on a 61x/64x conversion with just a b-pipe (ported manifold/head pipe) and rev limiter mod.
Important thing was my alignment seemed fine. Now I can clean up the garage and get this thing ready for paint, engine rebuild, etc. I'll be rebuilding the engine with a girdled head, minor freestyle porting, lightened flywheel, cold fusion couplers, and hopefully a wet jet mani and reworked 46 carb.
