Why won't my outboard go any faster & do I need a new one?

[GrahamM376]

There's an article here about checking for spinning hub, all you need is your lipstick https://www.boatingmag.com/how-to-tell-if-youve-spun-your-propeller-hub

 

[Spirit (of Glenans)]

I had a Tohatsu, 6 or 7 HP, standard shaft, on my first boat, a Leisure 17. It was mounted on a lifting bracket which allowed it sit well down in the water when motoring, and lift completely out while sailing. It certainly transmitted sufficient power to make headway against the current in the Malahide channel. Its unreliability provided many opportunities to practice using the last bit of forward momentum to catch any available mooring so as to get the tools out and get it going again

 

[tross]

If my memory serves me well this is the same hull as the Horizon 23.

I used a std shaft outboard on ta Hor23 without cavitation issues except when heeled over or very rough weather. Many Hor23 owners use a 4HP unit but all of them use a " high thrust prop" which gives a lot more push at lower revs. Is your prop a spline fitting of a dog pin fitting?

Tross

 

[tross]

Sorry I got interupted, if it is a spline I may have high thrust a prop as a spare

tross

 

[MissFitz]

Took my prop off yesterday & I do indeed have a spinning hub (didn't actually mark it & check but the rubber has clearly gone). Many thanks to everyone who helped with this, hopefully will now be able to reliably get out of the marina!

 

[VicS]

Took my prop off yesterday & I do indeed have a spinning hub (didn't actually mark it & check but the rubber has clearly gone). Many thanks to everyone who helped with this, hopefully will now be able to reliably get out of the marina!

Thanks for the feedback

 

[GrahamM376]

Took my prop off yesterday & I do indeed have a spinning hub (didn't actually mark it & check but the rubber has clearly gone). Many thanks to everyone who helped with this, hopefully will now be able to reliably get out of the marina!

May be worth keeping the old prop as a backup. Drill through the prop and bush and part way through the boss, then tap it and screw in a bolt. May be a bit out of balance but good enough as a "get you home" prop.

 

[MissFitz]

May be worth keeping the old prop as a backup. Drill through the prop and bush and part way through the boss, then tap it and screw in a bolt. May be a bit out of balance but good enough as a "get you home" prop.

This is interesting as a) it sounds like good advice & b) it sounds as though the assumption is that I would need a whole new prop. This is what the outboard place also said when I called them, which surprised me as internet-sourced info suggested I'd just need a new hub that could be pushed into the old prop. Is that definitely the case then? Don't want to spend £60 on a new prop if there's a cheaper option!

 

[nrcoyle]

This is what the outboard place also said when I called them, which surprised me as internet-sourced info suggested I'd just need a new hub that could be pushed into the old prop. Is that definitely the case then? Don't want to spend £60 on a new prop if there's a cheaper option!

I believe that the "press in" new hub is for much larger outboards, up to around 10hp or so i believe the props are disposable, as they don't cost enough to justify the labour of replacing the hub.

 

[MissFitz]

I believe that the "press in" new hub is for much larger outboards, up to around 10hp or so i believe the props are disposable, as they don't cost enough to justify the labour of replacing the hub.

Ah, ok, that makes sense. Thanks!

 

[GrahamM376]

I believe that the "press in" new hub is for much larger outboards, up to around 10hp or so i believe the props are disposable, as they don't cost enough to justify the labour of replacing the hub.

That's about right although prices vary wildly between sellers and whether prop is engine branded or after market. No bushes available for our Suzuki DF6 or the Tohatsu 9.8.