Lower Unit Shifting Problem

brianvolt7

Chief Petty Officer
Joined
Jun 7, 2008
Messages
423
I have just purchased a Bayliner with a 1990 Force 120. The lower unit prop shaft (lower unit not attached to upper at this time) does not turn freely when in neutral. However when shifted into the reverse position it locks the prop. It does not lock the prop when shifted into forward.
Q. 1. Is it supposed to move freely without turning the driveshaft?
Q. 2. Any recommendations for a remedy if you believe there is a problem?
I do not want to attach it and attempt to run it if this is not normal.
Thank you.
 

maxum247

Lieutenant
Joined
Sep 18, 2007
Messages
1,363
Re: Lower Unit Shifting Problem

I have just purchased a Bayliner with a 1990 Force 120. The lower unit prop shaft (lower unit not attached to upper at this time) does not turn freely when in neutral. However when shifted into the reverse position it locks the prop. It does not lock the prop when shifted into forward.
Q. 1. Is it supposed to move freely without turning the driveshaft?
Q. 2. Any recommendations for a remedy if you believe there is a problem?
I do not want to attach it and attempt to run it if this is not normal.
Thank you.

The driveshaft should turn with the propeller when shifted to forward gear, propeller should spin free in neutral and when shifted into reverse gear the driveshaft should turn along with the propeller.
 

brianvolt7

Chief Petty Officer
Joined
Jun 7, 2008
Messages
423
Re: Lower Unit Shifting Problem

I must have a serious problem then. I have installed the lower unit only to find the motor stalling out when shifted into reverse.
Any sugestions?
 

maxum247

Lieutenant
Joined
Sep 18, 2007
Messages
1,363
Re: Lower Unit Shifting Problem

I must have a serious problem then. I have installed the lower unit only to find the motor stalling out when shifted into reverse.
Any sugestions?

Disconnect the battery, pull the sparkplug wires, take the spark plugs out, shift the engine into reverse gear, (engine not running) put a socket wrench on the nut on the flywheel and turn the wrench clockwise (right), or turn it by hand with gloves and see if the flywheel and propeller turn or if they bind up.
 

brianvolt7

Chief Petty Officer
Joined
Jun 7, 2008
Messages
423
Re: Lower Unit Shifting Problem

The flywheel turns freely with some resistance when in reverse. The prop does not turn at all. However in forward and neutral the prop turns (in the right direction) with the flywheel and it seems like there is much less or no resistance. There seems to be no neutral at all. Do you have any recommendations for the next step?
Thanks for the help it is very much appreciated!
 

maxum247

Lieutenant
Joined
Sep 18, 2007
Messages
1,363
Re: Lower Unit Shifting Problem

The flywheel turns freely with some resistance when in reverse. The prop does not turn at all. However in forward and neutral the prop turns (in the right direction) with the flywheel and it seems like there is much less or no resistance. There seems to be no neutral at all. Do you have any recommendations for the next step?
Thanks for the help it is very much appreciated!

I don't know the answer, if I were to guess I'd think there may be a problem with the clutch dog in the lower unit that does the gear shifting or something is worn.

Use the search button at the top of the page and type in (lower unit) or something simular and see if this will help you find an answer.
Good Luck!
 
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