Re: [OMC-Boats] Volvo Conversion

Scott,

When I researched re-powering my 66 Sportsman several years ago I
looked at several alternatives, including conversions to:

modern Volvo/MerCrusier I/O, modern or vintage Outboard, and Jet Drive.

I had access to a dealer training/demo Volvo I/O unit at a fairly
attractive price. But there are/were several drawbacks to this
approach which I discovered in doing my research:

1) The OMC Transom must be heavily reinforced to become the primary
structural load bearing member of the gimbal mount. It isn't simply a
matter of covering up the original opening. You basically have to re-
engineer and re-build the entire transom and tie it into the hull's
existing underfloor stringer system. If you are going to do that, you
might as well re-build/engineer for outboard power.

2) There are major geometry issues, as well. The vertical dimension
issue crops up with respect to lowering the OMC Boat's original floor
to accommodate an Volvo or Merc powerhead.
(This was part of the reason the later stringers went to the short-leg
outdrive with the SelecTrim, so OMC was more industry compatible with
other OEM boat builders.)

  Most of the OMC boats, simply are too shallow to handle this
approach. The exception might be the 69-70 16 hull which has the
addition 4-inch dead-rise, but I've never measured this at the
transom, so it still might be an issue.

3) Lastly there are significant control/infrastructure issues: A)
Steering, B) Shifting, C) Throttle, D) Fuel, and E) Electrical.
While all of these issues can be solved with enough money (and you can
probably find examples where it has been accomplished), at some point
it becomes easier to either stay with the original OMC stuff or make
incremental/evolutionary improvements.

In my case the 71 OMC 215 replaced the 66 OMC 150. Originally,
retaining a stock/vintage look wasn't a main goal but now I'm glad I
did. The electric stringer has a lot more going for it than most
people give it credit for. At the same time I did pick up some
benefits: I now have a very reliable, safer boat that is smoother
running and steering and is much easier to obtain parts for. For
example, my boat now has the more easily serviced 5-bolt drive leg,
the square rubber boot (vs obsolete round rubber boot), the neutral
safety switch remote shifter, and most importantly, the safer
TruCourse steering.

As it turns out the Rochester QuadraJet is about as close as you can
get to modern EFI (at least throttle body types) in turn-key
reliability and operating economy. In fact yesterday, we did 3.5-hrs
of boating that included towing a 2-man tube and a fair amount of
staring/stopping/docking and 4-to-6 adults onboard. We logged 20 miles
and consumed exactly 7 gallons and this is at 6250 ft above sea
level. I'll take 2.5 to 3.5 gallons per hour any day and stack it up
against a modern EFI V6-powered I/O. I would admit that you could
probably beat that with a modern E-TEC Evinrude outboard, but the
conversion costs and acquisition costs would be much, much higher than
mine were.

Have a good day,

Lee Shuster

On Jul 31, 2009, at 4:37 PM, Scott Veazie wrote:

> Just for sake of generating conversation, has anyone ever considered
> converting over to a Volvo sterndrive setup? My 1965 OMC drive is
> working great, so I don't have any plans to change, but I was
> looking at the config, and a Volvo 280 drive combo might work. I'm
> sure you'd have to plug up the big hole and move the mounting down
> lower, but I wonder if it could be done.
>
> ~Scott
>
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Received on Sunday, 2 August 2009