18HP Evinrude Fastwin - Prop slipping

[ieuand]

Hi all,

This is my first ever post and I need some help and advice!

I've not long owned a 18Hp Fastwin and everything was going well with it, when one day in the sea, I was travelling along at a very low speed and attempted to open the throttle, the engine had high revs, but the prop was not moving. Whne I slowed it down, the prop then bagan to turn!

Anyway, I made back at a low spped and eventually go it home to have a play with it....with the engine not running and forward ot reverse engaged I am able to turn the popeller with my hands, but it is prop that turns, so the proppeller shaft and Propeller nut do not turn - when in neutral, everything turns when i try it. So it seems that there is something in the propeller set-up that is slipping.

I'm new to boats and outboards, but having looked at the engine diagrams I'm thinking that it could be any one of many different parts.....and then there is the question of where to get these parts (I'm in the UK)....

The Propeller shaft drive pin, seems to be fine and it sits nicely inside the clutch dof shifter (I hope this is making sense, as I'm not sure I know what I'm talking about!), which should stop the prop from moving, but move it does!

Any thoughts and ideas would be greatefully appreciated

Thanks
Ieuan

 

[kbait]

Re: 18HP Evinrude Fastwin - Prop slipping

You have a spun prop hub. Either have it re-hubbed, or find another prop to fit. Good luck!

 

[Rick-va3rzs]

Re: 18HP Evinrude Fastwin - Prop slipping

Kbait is right spun prop .. go to your local shop and pick one up or put an andd in your local wanted section

Good luck

 

[F_R]

Re: 18HP Evinrude Fastwin - Prop slipping

Anatomy of a prop: There is a rubber cushion that is bonded to the brass center hub. Then that whole assembly is pressed into the bladed part of the prop. The cushion absorbs impacts from hitting obstructions....or even just the bang from shifting gears.

What goes wrong is the bond between the rubber and brass hub breaks free. Then the brass hub spins in the rubber. It holds well enough to drive at slow speed, but slips when you give it power.

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

Hi all, thanks for all your answers.....it's all begining to make sense now as I think I grounded the prop on the sand the last time I used it, this seems to explain to me why the bond between the rubber and brass hub has come free (Very important lesson learned here for me!)

So now I have to find out if I can get it re-spun or try and get a new prop in the UK....First i need to find out what prop I have, I'll have a look when i get home from the office.

 

[bob1340]

Re: 18HP Evinrude Fastwin - Prop slipping

What year motor do you have? My 1971 model uses a shear pin and from what I can see has no rubber/bushed prop. I wager your shear pin has sheared.

 

[lindy46]

Re: 18HP Evinrude Fastwin - Prop slipping

What year motor do you have? My 1971 model uses a shear pin and from what I can see has no rubber/bushed prop. I wager your shear pin has sheared.

You can't see the bushing, but it's there. Your shear pin is actually a drive pin. When you hit something, the bushing is designed to take the impact, not the drive pin.

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

Hi Bob,

just off home to get the full details now - but it's a 1963 18Hp Fastwin....I think I need to identify this to be 100% sure. let me look this up and report back later

Thanks

 

[14ftgrumman]

Re: 18HP Evinrude Fastwin - Prop slipping

What year motor do you have? My 1971 model uses a shear pin and from what I can see has no rubber/bushed prop. I wager your shear pin has sheared.

I've had 3 of these motors- the prop can spin the hub and not break the drive (shear) pin. Don't ask how I lkearned this.

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

Hi again,

I think I've identified the Prop (based on what i found on this site). I think it's a Evinrude/Johnson 304684 9-1/4" X11.

Now I need to see about getting fixed and or finding the parts.

It's deffinately off a 1963 18 hp fastwin

Thanks
Ieuan

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

And finally, I think this is the parts diagram for the whole lower assembly.....I'm fairly sure it's right? http://www.marineengine.com/parts/vintage-evinrude-johnson/379270/catalog.html?http://www.marineengine.com/parts/vintage-evinrude-johnson/379270/37927000001.htm

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

Good news....using '304684' part in eBay, I found a 'Job Lot' of props (five in total), one of which was the '304684' and after arriving today its the exact one for the 18hp Fastwin - only cost me ?20 for all five - will now re-list the others on e-Bay.

I have also found a prop repair place in the UK and have sent the original off there to be fixed. So issues now solved and I'll end up with a spare!

Finally, very important lesson learned regarding Props and hitting the sandy floor!!!

Thanks again for all of your help

 

[F_R]

Re: 18HP Evinrude Fastwin - Prop slipping

Hitting the sand didn't cause it. It only finished off what was going to happen anyway. That rubber cushion was already deteriated and hanging by a thread. New/good props are ran through sand and rocks every day, and the hub survives. That's what it is there for.

 

[cajuncook1]

Re: 18HP Evinrude Fastwin - Prop slipping

Good news....using '304684' part in eBay, I found a 'Job Lot' of props (five in total), one of which was the '304684' and after arriving today its the exact one for the 18hp Fastwin - only cost me ?20 for all five - will now re-list the others on e-Bay.

I have also found a prop repair place in the UK and have sent the original off there to be fixed. So issues now solved and I'll end up with a spare!

Finally, very important lesson learned regarding Props and hitting the sandy floor!!!

Thanks again for all of your help

Don't sell all of the props.....keep one as a spare on the boat....never know when you might need it. Especially if your fishing out a sea.

 

[ieuand]

Re: 18HP Evinrude Fastwin - Prop slipping

More good advice, I will certainaly add the spare prop to my tool bag that I take out ever time.....I've also just purchased from eBay a CD Service manual for Johnson/Evinrude outboards (1956-72) and an original 'Shop manual' for Evinrude and Johnson outboards (56-72) - pulished in 1988.

So the plan is to start learing about these lovely old things and then not have to reply on expensive mechanics

I guess, I didn't really know the age or condition of the original Hub - but I'm learning everyday about ourboards and boating (only been doing it for 2 months) and at least I'll have a lovely new hub when the prop arrives back.