Alpha one leg. No drive

[syd]

Wotcha All,

We were headed from Burnham to St Kats yesterday, just passing Foulness Point when engine revs hit the roof and all forward motion stopped. Managed to drift into shallower water and drop achor to investigate. No obvious damage but when drive is sellected the prop does not move and can be sun freely and the engine starts to get hot as if the leg pump is not being driven and no water is being pumped in. The Mercruiser, Alpha one leg is only three years old and maintained regular. Any Suggestions? No forward or reverse and no leg pump.
Cheers all
Syd


Just going to have a good cry now.

 

[David2452]

Noises if any ?, can you hear anything when you try to shift ? does the control box feel any different when you try to shift ?

unlikely to be a spun hub as you have no cooling, the fault must be be between the engine coupler and upper unit. possible issue with shift mechanism. Answers to the above questions will help.

David.

 

[syd]

Hello David,
No noises, the shift lever feels the same and seems to be working all the bits but there is no clonk when pushed forward ie the drive engaging, the shaft between the engine and leg appears to be spinning but is it actually driving the leg? I suspect the drive coupling but can't understand why it would fail after only three years use. I'm having her lifted out tomorrow and removing the leg to investigate further. I think this is necessary because, like you said, a spun hub would not stop the pump, so the problem must lie higher up in the leg. What do you reckon David?
cheers
Syd

 

[David2452]

Sounds right to me, make sure you use an officioal Mercruiser (not mercury) dealer. good luck. Be interested in outcome.

David

 

[Freebee]

Having similar problems myself has made me a bit of an armchair expert. I think you have a flexi coupling between fly wheel and drive you can see this by looking down on the back of the engine. Put tipex or some similar marker on drive shaft and out side edge of the coupler. turn the engine over if the coupling is good when engine stops marks should be still aligned in the same way if not coupler has failed means pulling out the engine. Also have heard of drive shafts shearing. Good trouble shooting website for mercruiser on:

WWW.boatered.com

engines forum!

Let me know how you get on!