Long to Short shaft conversion

[kingfisher]

Hi,
I now have need for a short shaft motor for an inflaitable I have a Century + in GWO but yes you've guessed its a long shaft. Is it going to work out cheaper to convert it to short or sell it & buy a short shaft engine or is there a conversion available from anyone in the seagull world or can I put it on a spacer to lift it or is the engine too heavy _ Any comments or options on this matter greatfully recieved - Thanks in advance - Col.

[Keith.P]

Have a go at using a adjusting transom collar first, it all depends on how high you wish to go.
Have a look at:
viewtopic.php?f=2&t=1694

[Hugz]

When did BS add the thicker drive tube for the longshaft with the reduced diameter at the top to take the transom bracket? Tis annoying as it stops being able to adjust height. Earlier ones are fine.

[Shearwater]

I think the thicker drive shaft tubes are only on the barge pushers. These are thicker in the middle part, top and bottom have the normal diameter. At least on my two 102's this was the case.

[Oyster 49]

A jubilee clip works well as a height adjuster. That said it is easy enough to crop the required amount of the drive leg, exhaust, driveshaft and clutch rod.

[Charles uk]

If I remember right all Century + post 1969 (though it might have come in with the SP & the SPC in 1966) had drive shaft tubes that had an OD of 1.125", where the engine support lug & the water pump housing were fitted & an OD of 1.25" on the remainder, & a 10 gauge wall thickness in contrast to the 12 gauge wall used on the lower thrust models.

Making it impossible to shorten without the use of a lathe & a chrome plater, & impossible to "jack up" using hose clamps & bits of split plastic pipe.

The thicker tube wall was introduced on the higher thrust motors to prevent the drive shaft tube bending & rubbing on the drive shaft.

[Hugz]

I think the thicker drive shaft tubes are only on the barge pushers. .

I have an ED (late model 102, long shaft) with the thicker shaft reduced at top and bottom. Unfortunately I don't own any century or s/century longshafts but did have a long shaft 4/1 box (plus)that had the thicker shaft. Presuming that they had the thicker shaft for strength one would have thought that the reduction top and bottom would negate any strength advantage ie a chain is only as strong as its weakest link.

I note that Kingfisher mentioned that the motor is a century + which would presumably have the non adjustable drive tube.

Yep, raise the transom which would look odd.

Edit: Wrote at same time as Charles UK post. Good point re needing lathe. Shorten the other bits and pick up another short drive shaft.

[Charles uk]

Hugs the point at which they bend is at the fulcrum point, the thrust block.

[Hugz]

That makes sense.