Yanmar prop shaft coupling: should I use a torque wrench on its 4 bolts?

[BelleSerene]

I have an Ambassador rope cutter between P bracket and a Featherstream folding prop. Some twit, on disconnecting the prop shaft for alignment, has failed to ensure the fixed cutter was inside the striker plate on reassembly - so basically, the easiest way to fix this is while the boat's on piles doing antifouling, to disconnect the 4-bolt flange that connects the forward end of the prop shaft from the gearbox drive shaft, drop the prop shaft a couple of inches, locate it correctly under the hull, climb back on board and reconnect the flange. There are from memory four bolts ~4cm long, perhaps M10 or M8, going through this flange and fixing with (probably) nylon nuts.

Those 4 bolts: should they be torqued up to a particular level? Just done up as tight as two arms can manage? Or what?

 

[pvb]

As tight as you can manage with fairly large spanners/wrenches should be OK.

 

[colind3782]

FT

 

[alan_d]

FT

Fairly tight? Fully torqued? Finely tweaked?

 

[Tranona]

I have an Ambassador rope cutter between P bracket and a Featherstream folding prop. Some twit, on disconnecting the prop shaft for alignment, has failed to ensure the fixed cutter was inside the striker plate on reassembly - so basically, the easiest way to fix this is while the boat's on piles doing antifouling, to disconnect the 4-bolt flange that connects the forward end of the prop shaft from the gearbox drive shaft, drop the prop shaft a couple of inches, locate it correctly under the hull, climb back on board and reconnect the flange. There are from memory four bolts ~4cm long, perhaps M10 or M8, going through this flange and fixing with (probably) nylon nuts.

Those 4 bolts: should they be torqued up to a particular level? Just done up as tight as two arms can manage? Or what?

No need to do any of that. Just undo the cutter from the shaft, position the fixed cutter correctly and reassemble the rest of the cutter. Suggest you download the fitting instructions from www.ropestriper.com and it will all become obvious. 10 minute job with an allen key.

 

[colind3782]

Fairly tight? Fully torqued? Finely tweaked?

Something like that

 

[BelleSerene]

Thank you! FWIW I find an old note saying that my model AM10 (3 blade, 30mm shaft) has the more unusual ‘Bene clamp’ (Beneteau clamp) of two half pieces, which doesn’t look like their illustrations; and that I should 'undo the 4 bolts around the P bracket and re-engage the V. The striker plate comes off with 4 bolts, unlike the printed instructions. There should be a 6mm gap from the end of the L-shaped springs to the start of the single fixed cutter blade. Leave the rotating bit on the shaft.'

So I'll do that variant of Tranona's excellent advice and not risk loosening the drive flange!

Thanks to all.

 

[Tranona]

Thank you! FWIW I find an old note saying that my model AM10 (3 blade, 30mm shaft) has the more unusual ‘Bene clamp’ (Beneteau clamp) of two half pieces, which doesn’t look like their illustrations; and that I should 'undo the 4 bolts around the P bracket and re-engage the V. The striker plate comes off with 4 bolts, unlike the printed instructions. There should be a 6mm gap from the end of the L-shaped springs to the start of the single fixed cutter blade. Leave the rotating bit on the shaft.'

So I'll do that variant of Tranona's excellent advice and not risk loosening the drive flange!

Thanks to all.

You don't need to remove that, but you could if you wanted to, just undo the cutter from the shaft. Give you an opportunity to check the bearings while you are at it.