Does your Volvo Penta sterndrive keep kicking up when selecting reverse gear ??
The most common reason that most Volvo Penta drives kick up when selecting reverse is because the reverse lock pawls and mechanism are not free to move on the steering tube,-
The mechanism works like this - when in reverse the mechanism is naturally hooked over the locking pin by the springs, however when forward is selected the pawls are pushed up out of the way to allow the leg to kick up if it hits anything, but the mechanism must always remain in a fore- and aft position with relation to the the transom shield so that it can pickup the pin when needed.
In other words the drive must be free to revolve around the mechanism, but over time due to the alloy on the drive oxidising, marine growth forming and seals breaking, down the mechanism starts to 'stick' on the steering tube and trys to turn with the drive rather than staying put.The only real way to fix this is to remove the drive and the upper and lower gear housings then press out the steering tube from the intermediate housing, strip and clean the mechanism, and re-assemble using new spacers, bearings and seals, also ensuring that all the faces on the housing are cleaned, treated, painted and greased.
see the attached diagram for further explanation