Whaler Central - Boston Whaler Boat Information and Photos

Posted by lakedays on 08/14/23 - 9:11 AM

Just bought a 2005 130 sport with a Mercury 40hp four stroke efi. Pretty disappointed in its power with 2 adults and 2 kids. I suspect the prop needs to be changed but im new to boating so?

At full throttle off the line it struggles to plane and when it does it max’s out at 4500-4600rpm, not sure of mph but guessing low 20’s? I feel it’s worth mentioning the boat is at 5100 ft elevation as well.

Current prop. Black Mercury 10-3/8 14 pitch. Out drive is 2.00 x 1

Any suggestions?

Edited by lakedays on 08/14/23 - 9:12 AM

Posted by Phil T on 08/14/23 - 9:59 AM

With elevation comes reduced atmospheric pressure and combustion engines suffer performance degradation.

Electronic fuel injected motors experience less drop than carburated engines.

At 5100 ft above sea level you loose 6.1 horsepower. The 40hp is now a 33.9 hp engine.

The Black Max 14 pitch came with the engine/boat from Boston Whaler.

While the 130 Sport of that era was not a stellarly fast at sea level with a 40hp engine, in your location it is a bit of a dog.

To help offset the elevation, you should lower the pitch of the prop. I would estimate a 12" pitch of the same make and model of prop would help. Note the boat's top speed will not increase.

The only way to gain speed would be to replace the engine with more horsepower. A 60 or 70 would bring you back up to to the upper 30's.

Edited by Phil T on 08/14/23 - 10:02 AM

Posted by lakedays on 08/14/23 - 11:21 AM

Thank you Phil.

This morning I was doing more reading and noticed the new 130’s with a merc 40 come with a 4 blade 10.1” x 14” Spitfire propeller. What’s your opinion on that? Would that be better or worse than a 12p 10.3?

Posted by Phil T on 08/14/23 - 11:32 AM

Prop size is not universal since the blade geometry for each prop model different.

If you go with a Spitfire, you will still want to drop down in pitch. Maybe 12" pitch.

Posted by lakedays on 09/09/23 - 7:41 AM

I installed the 4 blade 10.375 12p and it made a noticeable difference. I would still like more power but I’m happy enough to stop looking for larger outboards for now. The new prop planes in about half the time it did before. Maybe 4-5 seconds with 2 adults and 2 kids (415lbs) 6gal of fuel.

Posted by wesley8808 on 10/15/23 - 6:13 AM

I have a 2006 130 with a 40 hp and had the same issues. I first added a SE Sport hydrofoil which helped a little but ultimately repropped as suggested above. When loaded down, it can still be a bear to get on plane but with me and my wife it is great.