228 sea trial

[fathergoose]

I’m in the process of buying a 2009 228 with a 250. During the sea trial it run up to 6000rpm with no problems but the speed was about 8 mph less than expected. Top speed was 39 mph. The bottom is painted but clean and fairly smooth, no water in the bilge and no curtains. It ran great nice and smooth just slow.

Any ideas why the lack of speed
Thanks

 

[Zebulon]

Prop???

 

[mmiela]

Seems a little slow my 226 with an F225 will do 37-38 in ideal conditions.

 

[Doc Stressor]

It might have a 15" prop and you are hitting the rev limiter at 6000 rpm.

My 226 with a 250 tops out at 44 mph with either a 17" or 16" prop.

Bottom paint can slow you down quite a bit if the surface isn't smooth even if it is clean.

 

[Ky Grady]

My 228 with F225 does 40 at 6K, running a 4 blade 16P.

Definitely check prop pitch.

 

[fathergoose]

Thanks for the replies. Turns out that Yamaha totally redesigned the f250 in 2010 and the performance numbers that I was using were from 2010. Also found out that the trim indicator was not operating properly. After the fixed the indicator we were able to get within 1mph of the published performance data for a 2009.

 

[ocnslr]

Engine trim during WOT evaluation doesn't need a trim indicator.

Start with engine(s) up just a bit. Find your open area and come up to about 5000rpm. Trim the engine up in small increments, watching the speed and rpm, until she seems "happy". Now go to full throttle, then bump the engine trim up until either you hear the change with the prop ventilating, or you see engine RPM increase with no increase in speed. Then just bump the trim down a touch, and that is your WOT speed and rpm. If you like, you can reverse course to run the other way for comparison.

Takes twice as long to finger type on my tablet as it does to actually do it.

You can use the rpm and gps speed to calculate prop slip as part of prop comparisons.

Helps to have rpm from an MFD or other digital instrument, instead of the older Yamaha tach gauges.