I am in the process of raising my F 200i4 on my 208 to the last hole. Have seen good results going to the 4 blade prop, and the fact that it appears to have better grip has got me thinking I will raise the Yam to see if I can increase my WOT by 100 rpm's of so. At the moment I am 56- 5700. Any of you running your outboards at their highest point with any results you would care to share. It is a simple process I have done before, just removing the old sealant/adhesive.... Sikkaflex is the pain.
Getting a raise
- Thread starter trapper
- Start date
Technically, you want the anti-ventilation plate of the motor to be in line with the base of the hull. If you raise it too high, the plate won't do it's job and will lead to cavitation.
I had issues when I repowered in 17 going from a 3.3 liter to 4.2. my 3.3 would spin up to 6,100 rpm with both the Yamaha saltwater series two and power tech os4 props. I buy the 4.2 and the dealer mounts it on hole 1 on the outboard ,which is the lowest deepest hole. I can't get the motor spin up past 5300 or so. Tried both Yammy and Power tech..so, I move it to hole two on the motor ( from the top) and did see appreciable gain in performance. This boating season I asked my serving dealer to raise her one more to hole 3.
I ran the boat Sunday for the first time but I was in the ICW between Flagler and St. Augustine and I didn't run her WOT,but at 3800 RPM I was cruising at 30-31 which took me going to 4000 RPM to break 30. I would suggest I am seeing noticeable performance gains. Ken at prop gods suggested if my antiventilation plate is below the water while on plane that's it too deep. I observed mine just at or slightly above the water line yesterday while on plane. Now the 228 is a bracketed boat and that rule of thumb keeping the antiventilation plate even with the bottom of the keel at the stern I am not sure ever applied.
I think without any knowledge of your boat the sweet spot for the boat is either hole 2 or 3 and not the last hole raising your motor to highest possible point. Please post your findings when you splash her.
I ran the boat Sunday for the first time but I was in the ICW between Flagler and St. Augustine and I didn't run her WOT,but at 3800 RPM I was cruising at 30-31 which took me going to 4000 RPM to break 30. I would suggest I am seeing noticeable performance gains. Ken at prop gods suggested if my antiventilation plate is below the water while on plane that's it too deep. I observed mine just at or slightly above the water line yesterday while on plane. Now the 228 is a bracketed boat and that rule of thumb keeping the antiventilation plate even with the bottom of the keel at the stern I am not sure ever applied.
I think without any knowledge of your boat the sweet spot for the boat is either hole 2 or 3 and not the last hole raising your motor to highest possible point. Please post your findings when you splash her.
I dealt with that same situation when I repowered my Grady with the 4.2 L. They changed the lower unit gear ratio from 2.0 to 1 on the 3.3L to 1.75 to 1 on the 4.2L. Thats about 12% higher gear ratio, I think. Made my new 4.2 with same HP rating unable to spin the prop off the old motor up to top RPM.
I have yet to gaze in wonder at my anti-ventilation plate while up on plane, so......I am hoping to get a glimpse when I wet the yacht with the Yam in the new "no holes barred position. The raising or lowering of the outboard is not a difficult event, I have the support and the chain hoist. Found the best way to get the old sealant (Sikaflex) out of the holes in transom and motor mount is a dull drill bit the same size as the holes. It is getting the new sealant around bolts etc., that seems to have a way of becoming part of ones wardrobe as the rubber gloves get a work out. I am wondering if the getting stern up a little more on plane has something to do with dragging a 100lb. kicker and 2 AGM Group 31 batteries back there. I will know more later this week when we get to play.
Correct, on a bracketed mount, the engine(s) should come up some. I believe an inch higher per foot set back from the transom.
Got out to play with the new Powertech 4 blade prop. All good! Did mange for the first time get to see the antiventilation plate looking back at me. Better results than the 3 blade Reliance. Thanks again Ken at Prop Gods.
Summertop511
Well-Known Member
All well and good during performance testing. Now get out in big following rolling seas where you have to trim up to keep bow up and the motor starts ventilating. I’d keep her down one from where you are at now.
Fortunately Summertop we do not get much of that "big following rolling sea" up here off the inside of the Island, If we do I have not found myself in it too often. Not sure if you meant trim or mounting hole down.