Motor Rebuild

[CrazyDryaton]

I currently have a 5.7 Yamaha stern drive in my boat. I'm going to completely restore my boat but I am wanting to change to Merecruiser. I would like to be able to rebuild using my same block. What advice could you give me for doing this or is it even a good idea. I plan on replacing my outdrive with a Bravo III. Thanks!

 

[Bondo]

I would like to be able to rebuild using my same block. What advice could you give me for doing this or is it even a good idea. I plan on replacing my outdrive with a Bravo III.

Ayuh,..... Welcome Aboard,..... Have ya found, or bought any of the replacement driveline yet,..??

You'll be further ahead to buy a Complete, pulleys to prop set-up, than tryin' to piece it together,....
Ole rotten hulls, with the driveline of yer choice is the Best way to go, as ya get all the crazy expensive little tiny pieces in the package, includin' the controls,....

You could then sell all yer Yamaha junk as a package,....
All of the accessories that are bolted to the Long Block to create the Bobtail motor, are very different, 'tween the Yamaha, 'n the Mercruiser ya want it to be,....

While the Long Block of yer motor is the same long block used by Merc, vintages could screw ya up,....
'n,.... A Long Block Crate motor is usually slightly cheaper than rebuildin' the long block yerself, 'n it's a fairly involved process, most Diy'ers don't have enough knowledge to complete, Properly,....

 

[Scott Danforth]

Welcome aboard, total agreement with bondo. pull out your motor, drive, AND controls. sell as a complete package, then get a complete pulley to prop mercruiser with controls and drop in. you will be thousands of dollars ahead.

 

[CrazyDryaton]

Thank you Bondo and Scott. Sounds like I’ll be getting a whole new setup. Any idea we’re i could go about selling the yamaha?

 

[Bondo]

Any idea we’re i could go about selling the yamaha?

Donno,..... Findin' somebody that would rather get 1 more lap outa their Yamaha might be tough, but those folks are out there,....
Ya see posters a couple times a year maybe in the "Other I/O's, 'n Inboards" forum,...
Not many Yamahas out there, in North America anyways,....

I usually ask whether they're in Love with the hull,..??
If so, Scrap the Yamaha, 'n drop in a Merc or Volvo, is My standard answer,....

 

[Scott Danforth]

try ebay and craigslist. there is always someone trying to keep their white elephant alive.

 

[HT32BSX115]

Thank you Bondo and Scott. Sounds like I’ll be getting a whole new setup. Any idea we’re i could go about selling the yamaha?

Howdy,

Welcome aboard --#3!

I did a similar thing about 12 years ago, removing the complete 87 model OMC 460 King Kobra and replacing with a complete 97 454/Bravo III

You might tell us a little more about your boat. How big is it? (What is it?)

As far as selling the old "stuff", I was able to sell most of what I had via ebay, craigslist, and word of mouth on other forums (not allowed here though)

I was pretty patient. I sold everything piece by piece. Your Yamaha stuff should still be fairly desirable since it's getting scarce.

If you're going to keep your engine, you'll still want to get rid of the Yamaha specific stuff like the manifolds, flywheel housing, starter (if different) and possibly the front stuff (alternator/PS brackets etc) trim pump, transom mount etc......... All you'll want to keep is the long block.

The best way to do it is to find a donor boat that is damaged (a tree fell on my donor boat but didn't hurt the engine/drive)

Remove all the Yamaha stuff and install the Mercruiser stuff. (you'll likely need to drill 2 additional holes for the Bravo outdrive transom mount)

Also, since you might also get an engine from a donor boat, you might decide to use the donor engine also. Don't try to put the thing together by obtaining everything piece by piece. That will be FAR MORE expensive than finding a donor boat.....and with the donor, if everything is there, it will be much easier to assemble.

If your boat is under about 21ft or so, a Bravo III might not be the best choice.

Cheers,


Rick

 

[CrazyDryaton]

Rick,
I have a 21ft Victory VIP runabout. I did find a guy that will build me a 383 stroker and put it in for $1500 I thought that was a GREAT price myself. As far as the outdrive I'm actually thinking about trading the whole Yamaha system for a used outdrive. Do you think I would be better off parting my stuff out and getting a donor? Also why do you say the bravo III might not be the best choice. I'm new to this whole thing so I'm not totally sure about everything. What would you suggest for the drive?

 

[HT32BSX115]

why do you say the bravo III might not be the best choice.

You have a fairly large heavy boat. Since you didn't indicate what it was before, I was thinking you had something smaller (like an 18ft boat) that might not benefit from a Bravo III

Your boat would absolutely benefit using a Bravo III powered with a 383. Aside from the low speed & reverse handling, you will be AMAZED at the incredible improvement in hole-shot performance.

My Mercruiser Bravo III package came out of a 1998 24ft Bayliner Cuddy. I was told that it might be too much for my 21ft Four Winns. (I didn't agree......I was replacing a 460 Ford and King Kobra!)

You could certainly trade the Yamaha package for a used outdrive. But understand that there's a LOT more "stuff" needed along with it. The advantage of getting a donor boat (with a good drive, transom, engine and accy's) saves you the nightmare of locating all the stuff you will need to complete it.

I didn't buy the donor boat but I removed from it everything from the steering wheel to the props. including the complete wiring harness front to back, the dash gages + dash harness!

Plus the shift, throttle, and steering cables, shifter (although I later bought a new Teleflex shifter) and all the shift linkage on the engine + trim cyls, trim pump, solenoids, wiring, and the complete transom gimbal mount.

It was a challenging project but not all that hard to install. I also had to do a bunch of engine compartment fiberglass work + completely rewiring the boat.

If I had to pay someone to do it, there's no way it would have been worth it. But now, I have an 87 boat with a 97 engine and drive with only about 200 hrs on it (since new) AND the yearly licensing for the boat is only about $25 .... Since the boat is so old, the insurance (liability) is about $100 per year!

There's definitely an advantage to fixing up and re-powering an older boat! (although I still want something bigger!)

 

[Scott Danforth]

if your putting a 383 in the boat, you really need to replace the yamaha stuff and go with either a volvo penta Duo-Prop or mercruiser bravo 3

if your getting a 383 built for only $1500, the guy isnt charging you labor and he is using cast pistons and a cast crank and possibly used parts. The scat rotating assembly is $900, machine work is $300 (clean, line-hone, deck, bore and hone), gaskets are $150, oil pump and pump drive $60, timing set $50, new head bolts $50

doesnt leave room for anything else including things like bearings, cam, valve train, clearancing the block, balancing the rotating assembly or machining the heads.

do you know what he is using for pistons? heads? etc. the correct parts are crucial to a marine build.
cast crank is OK for mild builds, hyper eutectic pistons are OK for nearly all builds, however highly recommend vortec heads and the proper LCQ style pistons. Highly recommend getting the motor balanced. Also recommend springing for coated bearings

 

[HT32BSX115]

if your putting a 383 in the boat, you really need to replace the yamaha stuff and go with either a volvo penta Duo-Prop or mercruiser bravo 3

I guess it might be appropriate to mention this here.......while there is NOTHING wrong with Volvo (except Volvo Penta XDP drives .....run fast from them)...............

I would suggest Mercruiser only because there's far more of them out there on the used market than Volvo. When I was looking, I was actually looking primarily for a 300+ hp SB/BB VP SX or Duo-Prop package for my Four Winns Liberator. (I even considered doing the famous DonS DPS install on my 460)

During that time, I found several SBC (300hp EFI) and 454/496/502 Bravo I and Bravo III packages. (and I bought one)

I never did find a (damaged) boat or a stand-alone package, VP engine/drive up here in the NW.

Not saying they don't exist, I just couldn't find one when I was looking in the NW (Portland, OR/ Seattle Puget Sound area)

I even considered buying new (VP and Merc were about the same price new, by the way......about $24k)