Whaler Central - Boston Whaler Boat Information and Photos

Posted by Jkunze on 02/12/18 - 8:58 AM

Im currently Repowering my 1967 Nauset , now going custom as I’ve already added a rear bench & am considering adding the forward casting deck, which would make it a custom Sakkonet.
I am trying to make some decisions regarding setup & need advice. I bought the boat two seasons ago with a 90hp Honda four stroke mounted to a CMC manual jack plate. It has always seemed transom heavy while planing off. Gas tank is mounted in the console with battery in rear, hull is dry. I have added a rear mahogany bench I built to factory specs & replaced the mahogany console. She is a pretty boat, but alas the 20 year old Honda 90 blew the head last season. I’m now having a new 90 Yamaha 4stroke installed. I am considering a hydraulic jack plate, to replace the frozen manual one, hoping to combat the high bow during planing off as I kept tilting the old motor to compensate before & thought raising/lowering might be better than tilting to keep the bow down. As I said I already have a manual jack plate that seems too low but the bolts are long frozen so it can’t be adjusted. The cavitation plate is currently well below the keel with the jack plate frozen at its lowest setting. Does it make sense to be able to adjust the height while under power or should I give up on the jackplate entirely? Also I am considering adding the original optional casting deck to the bow which would add weight forward of the console. I thought the added nose weight might do the trick. Any thoughts/advice would be appreciated.

Edited by Jkunze on 02/12/18 - 9:16 AM

Posted by Phil T on 02/13/18 - 5:02 AM

J-

The boat has a very heavy motor to begin with. I recall the older Honda 90's were near or at 400 lbs. That is alot.

Add the weight of the jackplate.

The engine reads to be mounted far too low.

When running (now) it reads as if you trim your engine out before the boat actually transitions onto a plane. This will make the bow rise even more before planing.

The advice for operating is to trim the engine in all the way in and then advance the throttle so that the boat accelerates quickly to reach displacement speeds. If you slowly accelerate it makes transition harder and longer. Once on plane, throttle to desired speed. Once there, adjust trim out till RPMs stop increasing.

With the new motor (~25-40 lbs less) and removing the jackplate (15-20 lbs less) AND the engine raised so the bolts are at least 2 holes up, the boat will handle MUCH differently.

See Reference Article on bolt mounting. http://www.whalercentral.com/articles...cle_id=106

Jackplates are good for very shallow running or making up for a wrong sized motor (25" instead of a 20" shaft.) It does not read as though you have a compelling reason to add the expense, weight or complexity.

Don't accept some cheap aluminum prop. Mount a good stainless steel prop.

Edited by Phil T on 02/13/18 - 5:04 AM

Posted by Jkunze on 02/13/18 - 8:29 AM

Thanks Phil. I do trim the motor all the way in to plane off. Sorry if I miscommunicated that. Still I’ve felt it planes off ass heavy since I purchased her two seasons ago. I agree with you about the jack plate too at this point. Thanks for saying what I was leaning towards. I’ll do away with the jack plate & ask my mechanic to mount the Yamaha higher with a SS prop.
I also thought to call Boston Whaler yesterday & asked about my current setup vs what I need. They’re very helpful & also said absolutely remove the Jackplate & have the cavitation plate set to 1-1 1/2” above the low point of the transom. Not sure why but the jackplate was on the boat when I bought it.
Sounds like a plan & thanks again for your good advice & to BW. I’ll report on how she’s running by April, after a 10 hr breakin. I’m going new with the engine so I’m expecting good results & hopefully good catches. Much to get done but hello to some early spring fishing!

Posted by Jkunze on 03/14/19 - 6:47 PM

It was a great season with the new motor on the boat. We put 40 hours on for the season last year & the old boat runs fast! Topping out at 40 mph at about 5600 rpm. I did not reinstall the jack plate & couldn't be happier about it. Also mounted the motor up a little. The boat planes off so much faster than it did with the plate. She's nearly done now. Everything is new & strong on her again. Only thing left now really is to get the 30-40 coats of bottom paint off the hull. Ugh, I think I'll get in a bit of spring fishin first. Happy 2019 season.

Edited by Jkunze on 03/14/19 - 6:50 PM

Posted by Jkunze on 03/15/19 - 4:01 PM

The motor is mounted at the third hole from the top. Prior the boat had a lift bracket mounted to the transom. That brought the motor about 6 inches back & the motor sat low on that bracket as well. It had been installed twenty years ago or so & it never should have been. It was hard to plane off before. Nose up no matter how I trimmed the old motor. Now it planes in a flash. Like I thought it should.