Long Shaft Design

You can talk about almost anything here

Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo

Post Reply
DaveF
Posts: 4
Joined: Thu Jan 21, 2010 8:18 pm
Location:

Long Shaft Design

Post by DaveF »

Hi,
I've acquired a LS motor and I'm wondering about the difference in the long shaft and short shaft engines in terms of how they are to be used. I've heard references to the height of the transom, the waterline, etc. I guess the bottom line is how deeply should the propeller be submerged to work as designed? If I mount the engine on a boat with a lower transom (putting the prop deeper in the water) would there be any negative effect?
Thanks...new at this game.
Dave F
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

i always use about 2 inches up the shiny part of the exhaust tube as a guide. much more than this may make the motor hard to start and also cause unnecessary drag. refer to the recent posts on shaft length. cheers
DaveF
Posts: 4
Joined: Thu Jan 21, 2010 8:18 pm
Location:

Re: Long Shaft Design

Post by DaveF »

Thanks...I appreciate the no-nonsense approach. I'll look for the other posts.
Vic
Posts: 629
Joined: Fri Nov 03, 2006 4:26 pm
Location: UK

Re: Long Shaft Design

Post by Vic »

post deleted
Last edited by Vic on Sat Jan 23, 2010 2:31 pm, edited 3 times in total.
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

british seagull service manual
service sheet no. 14
paragraph 4

"the correct depth of the propeller is with the exhaust outlet about an inch or two below the surface of the water... deeper immersion will affect both starting and performance"
as the boat is hardly ever exactly level in use i place my propeller a little deeper than this to be on the safe side.cheers
Last edited by billyboy on Sat Jan 23, 2010 3:04 pm, edited 1 time in total.
Vic
Posts: 629
Joined: Fri Nov 03, 2006 4:26 pm
Location: UK

Re: Long Shaft Design

Post by Vic »

Post deledtd Try to be helpful not appreciated. stick it however deeop you want,
Last edited by Vic on Sat Jan 23, 2010 2:32 pm, edited 3 times in total.
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

well ok, but it wont be a million miles away from 2" up the exhaust tube will it? on a small boat you have to keep it in the water so an inch or two extra wont hurt.and if you are happy to go with 4.5" and sometimes 12",then 2"up the "shiny part"would even seem a tad conservative.unllike you i am not an experienced sailor so i certainly wouldnt like to try 12"too often!

here is a small clip of my century pushing a 50 kg, 2.7 metre inflatable with 3 of my adult (a bit merry) friends.
not sure how deep they had the shaft that day but they seemed to have her going ok.will have to experiment more perhaps http://s799.photobucket.com/albums/yy27 ... 009004.flv]
User avatar
outboard
Posts: 299
Joined: Thu Oct 15, 2009 11:28 pm
Location: Ayrshire, Scotland

Re: Long Shaft Design

Post by outboard »

What's 2 or 3 inches between friends???
Thanks Billyboy, the clip makes me envious sitting here, however hopefully it won't be long till we're all back in the water. The engine sounded nice.

Gerard
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

the engine sounded nice.
only a seagull makes that sound.yours will be no different.and if you go boating often,there may come a time
when you are in a desperate situation and trust me,that little motor singing its sweet song will be the most glorious
sound you and your relieved passengers will ever hear.long live the gull!
User avatar
outboard
Posts: 299
Joined: Thu Oct 15, 2009 11:28 pm
Location: Ayrshire, Scotland

Re: Long Shaft Design

Post by outboard »

I can't wait to hear the sound. I have had one of my engines running and it sounded not quite right, now I realise the previous owner had the taper needle screw far too far in, now I'm having big trouble getting the damn screw out, the heads stripping. However I will hear that noise again.
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

dont be like the last owner.give her all the fuel she wants and let her go.
she will love it and reward you with that beautiful bark!
User avatar
outboard
Posts: 299
Joined: Thu Oct 15, 2009 11:28 pm
Location: Ayrshire, Scotland

Re: Long Shaft Design

Post by outboard »

would love to give her the fuel, any ideas on how to get this damn screw out. I'm now thinking about drilling it out. The manual says to have the screw either level or a full turn above the top, but this thing is right down inside the throttle piston.
User avatar
billyboy
Posts: 215
Joined: Sun Nov 15, 2009 2:10 pm
Location: Hobart,Tasmania

Re: Long Shaft Design

Post by billyboy »

if you drill it out you risk making it unusable anyway so you may as well buy a new assembly from john.
i think from memory that you have the villiers carb and i am pretty sure he still has parts for them
if not i know he has complete used ones that are not expensive.his number is on the SOS logo at the top of the page
give him a call. good luck!
Post Reply