065 HP Merc Lower Unit problems!

[kickinchicken]

Hello all:<br />I recently got a 1964 65 HP Mercury Serial No. 201788, my issues are as follows:<br />The guys I got this motor off of changed the water pump for me before I got it, brought it home and testing it out, it will not go in forward, it will go in reverse, but not forward. I was wonder if possible he could have put it back together wrong. I have removed the lower unit, every thing looks fine, splines are in great shape for the age. Could someone please give me advice as to what to look for and the proper way to line everything back up?<br />Also should there be any play back and forth movment in the prop shaft? NO side to side, but back and forth movement!<br />Thanks in advance!

 

[johnrob]

Re: 065 HP Merc Lower Unit problems!

I have the same motor type and spent a good few hours figuring out how the shift mechanism was designed to work (cos the one I had didn't work). I assume that you can shift into neutral OK? And that the positions on the control for neutral and reverse are the same as before?<br /><br />Stupid question but are you certain that it is reverse? In reverse you can rotate the prop by hand about 120degrees in either direction before it starts to turn the engine. In forward gear the prop rotates clockwise (looking from the rear) with a ratchet movement (i.e. it clicks and jumps a small amount every 70 degrees of rotation) and counterclockwise it tries to turn the engine. The default position for the shift mechanism is forward gear - it is spring loaded to engage forward. If you rotate the shift shaft until it is 'loose' (i.e. easy to rotate with your fingers) it should be in forward gear.<br /><br />If you still have the lower unit off you should be able to rotate the shift rod by hand (or pliers) to determine the correct positions for each gear (should be R-N-F in a clockwise direction looking down onto the shift shaft - R to F is only about 60degrees of rotation on the shift shaft). Make sure you keep rotating the prop while moving the shift shaft from neutral to reverse - the design of the shift mechanism makes it impossible to engage reverse unless the dog clutch is aligned properly - you could damage the mechanism of you force it into reverse.<br /><br />The best way to reconnect the lower unit is to put it into reverse and also put the control lever into reverse. Make sure you don't knock the the lower unit too hard as you are assembling it as it can knock the cam off the reverse position (reverse is when the cam is at it's highest position).<br /><br />When in neutral or forward you should be able to push the prop shaft in a small amount (1-3mm, you are pushing against a spring so it should pop back out again when you let go). In reverse there may or may not be any movement. If your prop shaft isn't spring loaded then there is a problem with the shift mechanism in the gearbox - either the cam follower has stuck, the spring is broken or the cam has been displaced.