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Old September 29th 10, 11:48 AM posted to
Bruce in Bangkok[_16_] Bruce in Bangkok[_16_] is offline
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Default Converting a 30' Pontoon from outboard to I/O

On Tue, 28 Sep 2010 21:59:45 -0700 (PDT), Tim

I went to a high school homecoming game/reunion last night and had a
blast. I ran into my cousin who I had gone out on his pontoon boat
last week and we did some talking about doing a river run next year. I
have previouslygone out with he and his family on the
Wabash river launching in at Vincennes In. I find out that when the
river is up you can go all the way up to to Hunnington and a bit
beyond which is near Ft. Wayne Indiana

Vincennes is the nearest launch to the Wabash for the both of us, and
if you consider Vincennes to be "0" on the miles, you can consider
that to make the full run north would be approx. 200 miles. We're
very well considering doing that with the pontoons next year. It would
make the perfect "mother ship" to carry all the stuff necessary to
make a really enjoyable run. Besides, as you can see by the map,
there's several ramps and marinas along the way. So if need be, stuff
can be had with out a great inconvenience.

We also talked about power. Making a run like that with a 1977 Johnson
V-4 would be fine if I hauled a tanker behind it because it loves to
drink the gas. I have in the past bought a couple of clapped out
boats to salvage the mercruiser engines and alpha drives in case I
needed them for future use for my 18 ft. Chris Craft. I know that the
ratings are different and the 85 Sea Horse presently pushing the
pontoon actually would have more torque than a 120 hp GM 3.0, but at
the sacrifice of double the fuel consumption, if not higher. Besides,
I'm more versed on working on an automotive style 4 cycle than a 2
stroke. And I think that eventually by force or by choice, the old 2
strokes are going to be fading out really fast in the near future, so
may as well entertain the thought of doing a conversion this winter.

He said he has a friend in Mt. Carmel who has a 28 ft. Harris who had
his converted over a few years ago, and suggested I talk to him about
his. He did tell me that a local welder in Mt. Carmel has done a good
job at converting several over to even putting 350 GM's in them!
Besides his shop rate being very reasonable, he's well versed in steel
and aluminum fabrication so that sounds like a good recommendation.

Then with the 3.0 GM I can outfit the charging system the way I want
to power the options I want as well, instead of relying on the 10 amp
stator 'battery charger' on the v-4.

What speed do you estimate this rig will do? What currents do you have
to buck along the way?