i got to tell you guys i did mine and got a a/f box . i dyno my motor 97jets all around running in the boat i had to down size 86 in pri 89 sec now my a/f 12.7 3000rpm12.5 wot pick up 4mph and the motor runs great. before i did this she loaded up and smell raw gas :cheers2: here is my a/f box that i use http://www.amazon.com/Innovate-LM-1-Digital-Ratio-Meter/dp/B000N8DL4G/ref=pd_rhf_p_t_4
I can see if you are doing different kinds of sweeps and loads on a dyno how the jetting would be different.
Lets say you make 500HP @ 4000RPM and it is loaded on the dyno. Your butterflies are at "X" position on the carb so you jet accordingly. Now when you are in the boat and cruising at 4000RPM your butterflies might now be in "Y" position cause you are cruising and maybe not loading the engine to the potential 500HP, you might only need 450HP to cruise at 4000RPM. With the different throttle positions Vs RPM's you might see a different signal to the carb which might affect jetting.
Mine was also a little different on the dyno then when I put them in the boat. And I was the one with the hand held Innovate LM1 AFR reading the numbers with the dyno guy. We spent 4hrs tuning my easy carb engines.
Also different exhaust could have affected his jetting. Maybe the builder and dyno guy wanted it safe when he left the shop.
PM me your address. I might have some extra components that I fabbed up. I will be out to the shop this weekend. If I find them I will send them your way.
Sounds like being "safe" gave away 100 horsepower by the speed increase he found. I don't think there is any excuse for that. Kinda defeats the purpose of using the dyno in the first place.
no lorazo came to the marina and took my boat for a ride:sifone:we work on my fuel lines and carb :sifone:the headers on the dyno were not the same as what i have in the boat. so i got a a/f box and dail my baby in!! very happy here me racing a supercharge wave runner that has mods .he runs 71mph on gps . :cheers2: http://www.youtube.com/user/SuperBajabob#p/a/u/2/jmnD9VV_jB0