Outboard prop shaft..and prop!

[scozzy]

Hi all

Maybe a silly query but a riddle for me at least...hoping for help!

So Ive got a mercury mariner 4hp 2stroke circa late 90's outboard i use as a tender/trolling of my little bilge keeler.Had it in the bucket to flush etc (another story!) and whilst engaging gears to give it a good run through i noticed no "swirling" in the water when in gear.........on inspection when in gear the prop shaft holds as it should although the prop itself spins freely any old way and as such wasnt engaged with the shaft under load or any old time!? My assumption is a lock nut/grub screw type of thing must be sitting on the the harbour floor somewhere? For reference the prop shaft just has a bullet shaped end with a split pin and prop sits in place with no visible means of support besides its sleeve,not the bolt and spindle arrangement that im guessing would be easier to solve!

In any case any helpful tips or hints much appreciated,be nice to think i dont need to replace the whole unit,no damage from any adventures to report as a symptom!

Cheers

L

 

[dehlerdave]

Do these have a shear pin through the prop to transmit drive? The 3.5 used to and it was easy to shear the pin if you engaged drive at anything more than tickover. I sheared a few before getting the hang of it.

 

[penfold]

There should be a shear pin through the shaft near the gearbox, the propellor fits over it with a pair of recesses in the forward end of the hub; then there would be a prop nut and a splitpin to secure.

 

[scozzy]

thanks guys,will investigate the pin situ more closely! the ease of shearing sounds interesting as my son dropped it into reverse on very high revs as we got to the mooring last week so it could of been then!!

Ill hope for an easy replacement via mr google

Cheers

 

[penfold]

Shear pins are readily available on a popular internet auction site, also online chandlers; if you have a local chandler they will have them if they're any good. If the latter take the motor with you to check it's the right thickness and length as they do vary.

thanks guys,will investigate the pin situ more closely! the ease of shearing sounds interesting as my son dropped it into reverse on very high revs as we got to the mooring last week so it could of been then!!

Ill hope for an easy replacement via mr google

Cheers

They're designed to break easily, as shear pins are cheaper than propellors or gearboxes, although shifting into gear at more than idle speed isn't a good idea.

For reference the prop shaft just has a bullet shaped end with a split pin and prop sits in place with no visible means of support besides its sleeve,not the bolt and spindle arrangement that im guessing would be easier to solve!

The bullet-shaped thing is just a fancy shaped nut; remove the split pin and it should unscrew with a spanner.

 

[mechanrik]

Hi all
i have just acquired a HIDEA 2.5 outboard motor and got it to run after cleaning out fuel tank and hoses ,and found the fuel tap was gummed up so cleaned that too,had the carb off and cleaned that put all back together ,but it will not throttle up has not done since day one ,the ony time it does rev up is when it runs out of fuel ? am i right in thinking it is constantly getting too much fuel,i have had carb off 4/5 times now and thoroughly cleaned ,however on first removal it was spotless ,so has previous owner put a new carb on with same problem? has anyone else had this issue?many thanks for any help .

 

[scozzy]

Shear pins are readily available on a popular internet auction site, also online chandlers; if you have a local chandler they will have them if they're any good. If the latter take the motor with you to check it's the right thickness and length as they do vary.
They're designed to break easily, as shear pins are cheaper than propellors or gearboxes, although shifting into gear at more than idle speed isn't a good idea.


The bullet-shaped thing is just a fancy shaped nut; remove the split pin and it should unscrew with a spanner.

Cheers for the great advice ?