Help Modifying OMC 31.8 cid

[LakeRacer99]

Heads...Joe says 1982 is the good one. Is it all 31.8 1982 heads or just 35hp? Why just 1982-What happened in 1983?

Joe/mike/anyone? have you made a chart with the part numbers and differences over the years for the 31.8 OMCs? I saw one for the 49.7 OMCs and wanted to make a similar one for the 31.8. I started one somewhere.

[LakeRacer99]

Does anyone have any pics of a 25/35 with a Second Effort case installed?

[Smokin' Joe]

Heads...Joe says 1982 is the good one. Is it all 31.8 1982 heads or just 35hp? Why just 1982-What happened in 1983?

Joe/mike/anyone? have you made a chart with the part numbers and differences over the years for the 31.8 OMCs? I saw one for the 49.7 OMCs and wanted to make a similar one for the 31.8. I started one somewhere.

Only the 31.8 c.i. powerhead. In 1982 they had a nearly 360 degree squish band, in other
years no more than 180 degrees. Why they produced it and then dropped it, no idea.

[JohnsonM50]

The ones I have done have the pump on the driveshaft above the couple square. It could be done that way with or without the top part of a gaercase. I got a few with bad inner's to do this with. You would have to create a base & plenum for the pump.. why I went that way.

[JohnsonM50]

Does anyone have any pics of a 25/35 with a Second Effort case installed?

That gearcase? I WISH!! LoLs, Funny I was just looking for that page pic, The head is what the one I have looks like. Calvin I'll see about a # when I can get to it. Maybe thats what the 82's had? The pad on this is different on the intake side.

[JohnsonM50]

I haven't but wish I had noted all iIve looked up [duh] A good place to start is BRP parts catalogues [on line]. There is broken down all the parts & part #s. No 2nd effeot stuff tho.. Sea Way Marine is the best bet to call & ask. Ive found 2nd effort solid mounts & this head I thought was.. or might be?, but never saw one of those neat gearcases.

[LakeRacer99]

...but never saw one of those neat gearcases.

There was one for sale last year on craigslist of all places, it was in phoenix or out in the southwest somewhere. The guy wanted $600 for it, I could not justify it. But that is the only one I ever saw.

[calvin]

The gear case to look for is also a 1982?....How do you verify that piece...serial # or length maybe?

[JohnsonM50]

The gear case to look for is also a 1982?....How do you verify that piece...serial # or length maybe?

Somewhere in this thread Joe mentioned which year lower units were doing best in GT PRO, don't think it was the 82, that year I've heard twice now had the strongest running power head.

[calvin]

Was the 1982 motor..a 35 or 30 hp motor?