Whaler Central - Boston Whaler Boat Information and Photos

Posted by 1970katamajs on 04/27/20 - 7:14 AM

I have a 1970 16' Katama...my present engine is a merc 75 four stroke...My engine is going into limp mode and I found that the water yube bushing was pinched and not seated properly. I replaced the water pump and water tube bushing and am hoping that fixes the issue. After all the problems narrowing down the issue I was considering a repower to a Yamaha F70 which is 100 lbs lighter that the Merc 75 four stroke. Does anyone have an F70 Yamaha on a Katama? that can provide performance stats? TIA

(changed to proper boat model for clarification)

Edited by Joe Kriz on 04/27/20 - 1:02 PM

Posted by Phil T on 04/27/20 - 7:51 AM

Lightly loaded, a Katama with an F70 will reach 35-39 mph at wide-open-throttle (WOT) when rigged and propped correctly.

Posted by reelescape1 on 04/27/20 - 10:22 AM

Good Youtube stuff by 3DSailor you might be interested in seeing. He takes an older 17' Montauk w/70 Yamaha 4S from NW to Key West. Similar set-up I think.

Posted by 1970KatamaVB on 05/19/20 - 10:37 AM

We have a 1985 Johnson 60 HP on ours and it will push it quite well. We can even pull freeboarders or tubes, though they can pull the boat a bit

Edited by Joe Kriz on 05/19/20 - 11:37 AM

Posted by biggiefl on 05/19/20 - 11:08 AM

FYI...I believe the 1985 60hp 2cyl was the last year of that model and replaced by a 60hp 3cyl in 1986. The 1985 60hp I believe is still powerhead rated hp so in todays engines would be more like a 55hp. I had a 1968 custom with a small gearcase mercury 60hp and yes she was pretty impressive for that small motor.