mercruiser prop dosnt turn

ground

Cadet
Joined
Mar 3, 2012
Messages
10
mercuiser ,we had to get towed in today we have a 165 petrol inboard with an mr leg motor runs fine, can still put prop in gear but it dosnt seem to be connected to the motor ,m wont turn , any ideas before I take it in for repairs please
 

Barramundi NQ

Petty Officer 1st Class
Joined
Jul 3, 2014
Messages
342
If the engine is running and the gearbox in forward or reverse, does the prop not turn? Does the engine rev hard but no forward movement? If so it sounds like you've done the hub of the prop. It lets go as a shear protection device. Especially if you hit something real hard you want the prop to let go before the gearbox breaks.
If not the prop hub, then you may have a linkage cable problem. Try engaging forward with the engine running and watch the prop and the center bolt. If the bolt is spinning but the prop isn't you need to get a new prop our get it re-bushed.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Usually one of 3 things. Spun engine coupler (engine out to fix), spun propeller hub (replace/repair propeller) or a broken drive shaft or stripped gear (replace/repair as required)...

To check the prop hub, mark the propeller outer and inner hubs. Then take the boat back to the water and try it in gear. If the marks have moved, replace/repair the propeller...

To check the engine coupler, remove the drive and have a look at the yoke splines and the coupler splines (coupler splines can be seen in through the gimbal bearing).

to check gears and shafts, with the drive off, put it in forward gear, hold the prop and try to turn the input yoke. If the yoke turns without the prop moving, split the drive. Check the drive shaft and if that's ok, take the top off the drive and have a look at the top gear set.....

Chris......
 

ground

Cadet
Joined
Mar 3, 2012
Messages
10
the prop is brand new , when you put it in gear you can feel it dragging on gearbox ,I think its something to do with transfer of power from motor to leg ???
 

alldodge

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Mar 8, 2009
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40,582
the prop is brand new , when you put it in gear you can feel it dragging on gearbox ,I think its something to do with transfer of power from motor to leg ???

I think you have something busted in the outdrive (leg).
Disconnect the shift cable from the shift plate on the engine. Try to engage the drive by moving the cable manually. If it goes in gear and is OK, then probably the cable. If you still have issues, pull the drive and inspect
 

Dadoffive

Seaman
Joined
Oct 20, 2013
Messages
70
Is the throttle only button popping out like it's supposed to or is pushed in all the time?
 
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Fun Times

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May 16, 2009
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when you put it in gear you can feel it dragging on gearbox ,I think its something to do with transfer of power from motor to leg ???
Turning the prop by hand while in gear I'll presume? If so, then to test your theory see if you have access to the rear of the engine so that you could mark your stern drives input shaft and engine coupler then with the drive still in gear, turn the prop a little and recheck your alignment lines on the coupler and shaft.

If not by hand, then the marked lines should still be done then checked after a water test while your checking the propeller hub lines described by Chris above.;)

Hope you find the problem soon, good luck.:)
 

Bondo

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Apr 17, 2002
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70,468
the prop is brand new , when you put it in gear you can feel it dragging on gearbox ,I think its something to do with transfer of power from motor to leg ???

Ayuh,..... Welcome Aboard,.... I believe yer Right,....

Pull the drive, 'n you can investigate, 'n see where it's broken,....
 
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