Backlash measurment 68 Merc 110 9.8

[Gary Spence]

Not sure I interpeted the backlash procedure. When I turn prop shaft to the point that the pinion gear does not engage the reverse gear there is about a 1/8 of a turn clockwise/counter in the prop shaft to drop in. My tolerence should be between .003-.005. Is this just a touchy feely thing or do I need something to measure with? Seems like this is just the cam.

 

[Laddies]

Re: Backlash measurment 68 Merc 110 9.8

Gary, if you are carefull and don't misplace any shims you do not have to shim a unit to change gears or bearings, they are all + or - .001 to .002 on any Mercury built lower unit, you are really shiming the case not the gears and bearing, most of the dealer talk about shimming is to scare people off. After 45 years at this you learn a couple of tricks, actually I had a freind that was a Mercury service instructer tell me that about 40 years ago and found it to be the truth in all but a couple of cases

 

[Gary Spence]

Re: Backlash measurment 68 Merc 110 9.8

Thanks Laddies! I won't worry about it. Just thought that I might get it back to spec if I had to pull the propeller shaft to get to the cam. Read that if you were not careful changing the shift shaft oil seal and o ring that it would pull out of the cam.
Do you know if a oil seal and o ring for the propeller shaft comes with a lower unit seal kit. The one I am getting has 17 parts. Part # 26-77066a1
68 merc 110 9.8

 

[Laddies]

Re: Backlash measurment 68 Merc 110 9.8

They should

 

[Gary Spence]

Re: Backlash measurment 68 Merc 110 9.8

They did in fact. Didn't change the prop shaft seal as it tested good. The new one that came with the kit had a smaller diameter hole in seal base but fit the shaft. Decided to leave it and do a test run. The only problem I had was installing the upper pump housing seal. Slightly bent going in but straightened it out with a screwdriver. The thing started a little crooked as I was using a socket and swing press. Think all is well.