Offshore 27 Re-power with Twin Yamaha F300 4.2L

[conch]

This is a first report of a test run [of a Boston Whaer OFFSHORE 27] with my recent engine replacement [of twin Yamaha F300 4.2-liter engines], but not many details for now as this was more of a shakedown trip.

The [Boston Whaler OFFSHORE 27] hull has two fresh coats of Micron 66 bottom paint, 243-gallons of fuel, the usual gear on board, and three people. I intended for my crew to take notes, however that assignment sort of faded away above 42-MPH.

[The Boston Whaler OFFSHORE 27] boat jumps on plane, and at 6,000-RPM we observed 57-MPH. The jack plates were at 50-percent and engine trim at 50-percent. The engine speed was still climbing, and, at this point, I backed off. Performance is beyond what I expected. Cruise will wind up around 3,500 to 4500-RPM, I think.

The propellers are Yamaha 19T from my old 1992 250-HP engines with carburetors, which were removed. Next I will try a pair of Yamaha SWS II 15x21 propellers.

I have added the extra battery charging leads to each engine and added water pressure senders. We put in new Seastar steering cylinders, as well. The electronic engine controls are great. I did not think they would be this nice. The engines are quiet and I can not tell if they are running from the helm at idle. Push button starts and stops are new to me also. We also took the opportunity to replace the electronics: Furuno and Sitex--out; Garmin--in. Also totally re-built the triple-axle trailer, adding electric-over-hydraulic disc brakes. [To discuss this topic, see the thread in REPAIRS and MODIFICATIONS--jimh]

Back at the dock you had to chisel the smiles from our faces. Real stats to come.

I saw on the Yamaha color display [indicating] 1.7-MPG at 50-MPH, but I have not yet set up the display, so I don't know what it was reading. Initially I had trouble seeing the engines on my Garmin chart plotters, but that was corrected back at the dock and was a simple menu setup item I missed.

--Chuck

[msirof2001]

That's my favorite Whaler model with my favorite Yamaha model. I am curious: what will be your optimal cruise speed and MPG?

[littleblue]

Wow, congrats! Great boat and great motors. Please do post results (and photos!).

[PJMSport15MY1984]

Chuck--you definitely sound like you found an ideal re-power solution. The new re-power sounds very fast.--Paul

[flymo]

Chuck, need some pics of that bad boy!

I always loved the Offshore 27, and if I hit the lottery I'd get the version of it that's still available from Brunswick CGP. I have a friend who has one of the 4.2s on another boat, and he loves it.

Tim

[conch]

I will try to get up some pictures. I am probably the last person without a cellphone or camera. Lots of company this time of year in the Keys and someone will help out with photos I'm sure.

The grandchildren want a stereo installed and hinted at a Christmas gift for the boat. I also have new radar, Go Light, VHF,and antenna to install.

When none of the local boatyards would do my re-power I did it myself. I only transported the boat to a local icehouse with a forklift to lift the old engines off and new on. Already owning the boat and buying the engines on my own from Texas, none of the local yards had any interest in my re-power and all were "too busy" for me. Having my own trailer, I brought her home to do the rigging work. I will be finished soon, but I keep renewing things I see needing updating as I take something else apart.

Chuck

[Jeff]

Short Video Chuck sent me of his 27.

https://youtu.be/Ir-UF2cFltA

[conch]

Jackplates Installed

[conch]

helm.jpg (29.81 KiB) Viewed 20393 times

Garmin Chartplotters installed

[flymo]

Really nice - thanks for the pics!

[littleblue]

Any update on the fuel consumption and MPG? This boat and motor combo is the stuff that dreams are made of--at least mine.

[conch]

Loose Yamaha engines I purchased from Texas coming home on the trailer.
When I arrived from my motel in the morning Chris and Kent had them already bolted onto the trailer I dropped off the previous evening.

The engines and their warranty had to be transferred to me by a Yamaha dealer. I could install and rig them but all had to be checked and signed off on by a dealer after operational testing of all systems. This is something you pay for per engine, all is done now,and my warranty cards came in the mail. I'm good til thru 2019. The new electronic controls needed to be matched to the engines, so I purchased the patch cord and software online and the Yamaha YDS system 1.33 ran on an old laptop and plugged into the engines test port.

Andy at SIM Yamaha answered my questions and provided great prices and prompt shipping.
Hope to get some time on the boat soon as the Thanksgiving wave of company is leaving shortly.
Chuck

[Apogee]

Those are some big engines. Did you buy them new or used? I do not see the shipping crates. I bought one F300 with all the controls and harnesses, and it cost me as much as a new car.

[MVeeWhaler]

Really sweet set-up! What is the shaft length on those motors??

[jimh]

The sidebar topic of trailer brakes has been moved to its own thread.