Yanmar 4BY2-180 RPM's on 2013 R25SC

[Capnron]

Not a whole lot mentioned in the manual, but what is a good max cruising RPM? I get 4200 WOT and it will reach about 18 kts, and at the 3600 recommended somewhere here I only get around 13 kts with 2 people, half a tank of gas, little water or black water and light wind. I purchased this recently and cleaned out some weight, it has a clean new bottom but has been in the water a while. It seems like with a top of 18 I should be able to get 14-15 or so. I have played with the trim to optimize the speed that I get.
Ron

 

[Boatdreamer]

Hi Capnron, here's information from our 2012 R27 with the 4BY2-180. We just did a 350 mile trip to the Bahamas and this is what we found out. We were fully loaded with fuel, water, food and dinghy with outboard. We ran at 3200 RPM's for most of the trip which was between 11 and 12 knots. We burned 6 gallons an hour and the engine temp ran 195-196. I read somewhere that you shouldn't run more than 80% of max RPM for more than 5-10 minutes. The max RPM is 4000, that is why I don't run more than 3200. We also have bottom paint. I've seen 20 kts at 4000 RPM's lightly loaded in fresh water. I hope this answers your question.

Tim and Donna
Gratitude

 

[Capnron]

Thanks. Better safe than sorry.

 

[PhilR]

On a good day, my 4BY2-180, 27' Tug will do 20 knts. At 4,000 rpms.