how to test gears are working when the lower unit is lowered?

Its a 75 model 650 - 65hp, I bought this recently and I have the lower unit removed from the body of the motor.. how can I check if the forward, reverse gears work? what should spin what direction, what noise etc..?? <br /><br /> I need this clearified, abit confused while I tried to test it myself.. Can an expert tell me please??

Re: how to test gears are working when the lower unit is lowered?

I hope I am not lieing....been awhile and things do change.<br /><br />Merc uses a splined shaft to do the shifting. By rotating the shift shaft just a few degrees you can go from F-N-R.<br /><br />With the lower unit in a vise (cushioned to prevent paint damage) you can put a pair of vise grips on the shift shaft (holding with one hand) and grasp the prop with the other (hand).<br /><br />The shift shaft is not hard to turn so if you get any kind of resistance, go the other way. The whole shifting process takes less than about 45 degrees of rotation of the shift shaft.<br /><br />When you find N (Neutral) the prop spins freely.<br /><br />F (Forward gear) locks the prop in one direction and if you put pressure on it in that direction you will see the driveshaft (coming up out of the water pump) turn.....and yes there is a lot of resistance....you are rotating the impeller in the water pump. Rotating the prop in the opposite direction will activate the slip clutch and as you spin the prop you will hear a clicking sound and the driveshaft will not turn.<br /><br />R (Reverse) locks the prop in both directions.....no slip clutch function. Turning the prop in either direction results in drive shaft movement.<br /><br />Simple as that.<br /><br />At least that's the way it used to be.<br /><br />Mark

Re: how to test gears are working when the lower unit is lowered?

Mark's right there. Although Merc had a couple of different shifting mechanisms, called EZ-Shift, and Cam Lock or something like that. One of the units doesn't have the slip clutch, so if your prop doesn't slip (click-click-click) in the opposing direction, don't freak out, could be a different shifting mech.

Re: how to test gears are working when the lower unit is lowered?

thanks for the info mark&studly..<br /><br />this is what i tried..<br />as you mentioned, seems like this whole shifting from f-n-r is in like 45deg. increments..<br />i rotate the shifter shaft in ccw rotation, i hit F then N then R.. so...<br /><br />when in:<br />F - the prop rotates ccw, but in cw rotation it clicks, clicks..etc..<br /><br />N - it spins freely both directions<br /><br />R - i might be confused or not remember too well now, it doesnt spin either direction!? <br /><br />is this right??

Re: how to test gears are working when the lower unit is lowered?

Just a minute. <br /><br />In F you said that the prop rotates ccw. Do you mean that it rotates as you turn the drive shaft?<br /><br />Or, are you grasping the prop and it will allow you to turn it ccw at least 1 revolution by hand with light pressure? I hope your answer to this is NO! <br /><br />You do however, have to turn it a few degrees ccw to get the gears to engage but once they engage, you meet with significant resistance (like what you feel in R).<br /><br /> The click you hear rotating cw in F is what you want to hear.....that is the slip clutch clicking which works in that direction only. That's good.<br /><br /><br />R you said it doesn't spin in either direction. This IS CORRECT if you are grasping the prop and don't attempt to turn hard enough to turn the drive shaft (coming up out of the water pump).<br /><br />But if your test in F was done the same way as the test in R, where you grasp the prop and it freely turns ccw (at least 1 rev) you are not engaging the drive dog in F. Bad!<br />------------<br /><br />Do us a favor (you and me) go back and put it in F and insure that light pressure on the prop in the ccw direction does not cause the prop to rotate.....light enough that you don't turn the drive shaft coming out of the water pump.<br /><br />It should not rotate ccw (more than a few degrees as stated). <br /><br />If, in F position, the prop rotates freely (like in N) in the ccw direction, you have a problem. Hope you just got confused on the data you supplied to us.<br /><br />Let us know.<br /><br />Mark

Re: how to test gears are working when the lower unit is lowered?

[oops]

Re: how to test gears are working when the lower unit is lowered?

Also, the drive shaft needs to be spun when shifting into reverse or the unit might become damaged.

Re: how to test gears are working when the lower unit is lowered?

Originally posted by Eli Lilly:<br /> Also, the drive shaft needs to be spun when shifting into reverse or the unit might become damaged.

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This is so true. I almost thought my lower was a write-off. Couldn't get all gears. Then I remebered that the engine is turning the drive shaft all the time when I'm selecting gears. Not the prop. It's a b!tch to turn (Tight with all the seals and water pump (Make sure you turn it in the right direction), then while sum1 is turn the shaft you can try to select gears.

Re: how to test gears are working when the lower unit is lowered?

I need to differ with you on this one, MercFan. The clutch dog always turns with the propshaft, it slides on splines. The reason things need to be turning is to allow the clutch dog to engage the reverse gear. This is not an issue with forward, because it is spring loaded and the teeth on the dog ratchet in forward. But in reverse you are pushing the dog into the gear and things have to be moving so the teeth can engage. BUT it doesn't matter which is moving (the gear or the clutch dog), so you can rotate the prop shaft instead of the drive shaft to shift into reverse. And it is much easier to do that way!

Re: how to test gears are working when the lower unit is lowered?

Thanx Bill!<br /><br />Gonna safe me a lotta elbow grease next time around!