Powering a 1973 16 O/B

[TuxedoPk]

I am picking up a 1973 16 OB this weekend sans the 200hp engine that was pulled from the boat and sold separately by the previous owner.

The prior owner suggested putting in a 150 because he felt the 200 was too much for the boat. I've seen people on the registry with 135s to 225s.

Can anyone share what performance level I should anticipate at varying engine sizes?

[BigGrizzly]

The boat is rated for a 135 on the sticker and in the brochure.

[olredalert]

-----Saw one down in the Caymon Islands this past week with a 175 Johnson.Boat and motor had seen better days but was still being used commercially to tow an inflatable with about six people in it.Ran good according to the guys running it.....ol red!.....Bill S

[McGary911]

TuxedoPk, Frank C has one, with a 115 i think. Before deciding the power you want, make sure that transom is still solid. If its been running around with too much motor for long, there can be enough damage to make even a 150 unsafe, if not repaired properly. Make sure you get some pics for us when you get her home!
Ol'Red, where did you see the 16 OB in the caymans? I was down there on 7 mi beach recently, and was certainly checking the local boats, no Donzi tho. My dad is gonna move down there in a year or so, so Im gonna get to know Grand Cayman pretty well i would think :D

[Dredgeking]

merc's 300x.

you can never have too much, but you can use too much. wink

[TuxedoPk]

LOL.. Somehow I think Merc 300s would be a bit overboard... Then again, I just closed on a 14F today with a 354:) (seriously) It is being shipped and I'll post pics when she comes in.

Scott's going to take a look at her with me; I feel really confident that if the boat has any issues, he'll spot them in a minute. I'm going with his suggestion to power the boat with 150s.

My original question had more to do with what speeds could be obtained at varying engine sizes.

[MOP]

That old I would peel it and redo the transom and tank without thought. We had one around here with a 200 Johnson, jacked with tabs. It ran nice the guy did not seem to have any trouble with handling it. As I remember it was not as fast as I thought it would be, an 18 with a small block Volvo setup which I believe was about 250hp got away from it, not real fast but did show its transom.

[mattyboy]

Tuxedo,
John Benkoczy( board member) has a beautifully restored OB 16 with a 175 Johnson on it it flies!!!!!!! he docked last season by me in Greenwood Lake drop him an email he's a good guy he'll answer any question you have , the OB's have a lot more free board then the V8 16's every time we pulled up near him my friends said my boat looked like it was sinkin.....or that I need to loose weight eek!

Matt

[Formula Jr]

Big Griz points out an important fact here. If the boat was CG rated at 135 and you go bigger, there may be insurance problems and inspection problems down the road if they have that in a data base anywhere. Its funny that OBs had a HP rating, where as I/Os and inboards/ V drives never did.

[Dredgeking]

jr., i think that's an old wives tale. coast guard rating where? i didn't see no stinkin coast guard rating wink

if you re-work the transom set it up for twin counter rotating 300x's. :D hell, you have all that extra free board.

[BUIZILLA]

Hmmm..
4 stroke outboard ???

interesting.. :p

J

[Dredgeking]

mad, i understand the rules and regulations. i'm just saying that maybe the cg plate disappeared. maybe it was stolen. hell, maybe there never was a cg plate. hmmmmmmm. maybe you find the plate. maybe it was hiding in the bilge, maybe the plate that you found states the max hp at 330. hmmmmm. then you could slap a 300x on it. i'm saying that just about anything could happen to that cg plate. wink

[RPD]

I have had a 16 OB for about a dozen years... had an Evinrude 140 for years.... 2 years ago I repowered with a Yamaha 150 EFI (Vmax... Bass motor)... power is NOT a problem and I think it could easily handle the 175... only problem for me was a) the 175 of that motor wasn't available that year and b) I didn't want to chance moving the power curve too far up the mph range and lose pulling power in the skiing speed range...

What is a problem is weight and freeboard when sitting still.. once on a plane, no problem... my 140 was about 375 lbs and OK, John Benkoczy's 175 (see above) is about 390 lbs or so... my 150 is about 445 lbs... by that point the transom is getting very low in the water.... the Yamaha HPDI motors are about 365 lbs and would probably sink it...

The best thing I did was close the control cable hole in the motorwell just forward of the transom... I then moved all the cables to the forward bulkhead of the motorwell and enclosed them in the flexible conduit that is used these days... steering was converted to hydraulic, the hoses do not pass through to the motorwell, rather there are fittings passing through and the hoses attach inside and out... thus a watertight arrangement.

PS: when we took the motor and deck off we inspected the transom and stringers, which were in perfect shape and needed nothing... my glass man was quite impressed by the strength of the contruction.

[TuxedoPk]

What is a 354?

It's a typo for 327.

[Shanghied Again]

I have the brochure boat from 1973 she has a 115 Merc the origional engine was an evinrude 115, The boat runs a solid 55 mph. The most I would go is a 150.

[TuxedoPk]

Today has been one of those days..
I posted my thread about this boat in the Donzis for Sale section under the heading "Condition of 1973 16'. Aside from the wrong forum, it is a 1972. At least Donzi is spelled correctly.


The thread has a pic of the boat and some questions concerning "issues" with the boat which may or may not be important. I am supposed to pick the boat up this weekend, so this is my last chance to identify any issues and make sure I don't overpay.

[Ben G]

TuxedoPk
This is an interesting question. I asked the same question when looking to change a 150 Merc( old six in line) and received some interesting replies.Some 16 owners, in Ausralia and the US I am sure, run up to 225 on the back at speeds of up to 75 mph.I put a 200 on the back and the hull handles it very well.A couple of pieces of information seem critical however.As others have indicated the transom needs checking and I was advised that Donzi did at one time produce plates to strengthen the transom for those wanting higher power.You will at some point need to acquire dual cable or hydraulic steering for safety and control at higher speeds.A number of 16 owners with higher powered outboards also use 6-8 inches of setback via a sternjack which I am told significantly improves handling and performance.There may be other bits of information that are relevant but as best I can assess thes are the critical ones.At the end of the day it is still the way to go to create exciting affordable perfomance.