RT188 - Setup Questions

[mattfish11]

OK - so I had my Mercury Fourstroke 75HP flashed to a 115 put on my Ranger RT188. Also installed a 5" jackplate on the back. The dealer that installed the motor put the motor "at the standard position" - which is the mounting the motor so the cavitation plate is flush with the bottom of the boat. This puts the center of the prop 8" under the boat bottom ("prop to pad"). Seems pretty low to me. Curious what RT188 owners have as their setup?!?

[Skeeterbait]

Way too low. You will likely have handling problems with it that deep, let alone a lot of excess drag. I would not want it any deeper than 5.5 inches measured center of prop shaft to the base of the keel (not the tip of the keel) With a 4 blade prop like the Spitfire X7 I would want it even shallower than that. I am currently experimenting with running mine at 3.5 to 3.75 inches using an X7 prop with a hydraulic jack plate and so far I am liking the results. But I need to get a higher pitch prop before I make my final decision. I was running at 4.5 inches though with good results.

[mattfish11]

Way too low. You will likely have handling problems with it that deep, let alone a lot of excess drag. I would not want it any deeper than 5.5 inches measured center of prop shaft to the base of the keel (not the tip of the keel) With a 4 blade prop like the Spitfire X7 I would want it even shallower than that. I am currently experimenting with running mine at 3.5 to 3.75 inches using an X7 prop with a hydraulic jack plate and so far I am liking the results. But I need to get a higher pitch prop before I make my final decision. I was running at 4.5 inches though with good results.

That's what I was afraid of... I'm gonna raise it to about 4" below - then I can use the jackplate to dial in as necessary. Thanks again buddy!

[ZR1driver]

Rt188. 115 pro xs . 4 in set back. Mine is at 5 inches

[mattfish11]

OK - took the boat out for a quick trip to run it and see how she does. I hit 40 pretty regularly and hit 41 once (wind to my back).

I'm at 5500 rpms and I'm really surprised at how very little bow lift I get. This is where I want to be as far as rpms.

I'm about 5.5" prop to bottom of boat and going to be adjusting the motor a little bit farther up - probably get it to about 4" and run it again. See what happens.