100 HP Merc I6 Lower Unit questions

[JWH0420]

i have a question in regards to working on the lower unit. i had a seal fail at the bottom of the water pump on the input shaft and in attempts to do the job correctly i want to remove the input shaft to clean and inspect other components ive got the case down to input shaft bearings gear and forward gear still in case got the nut removed from the bottom of the inputshaft where the gear is but cannot seam to remove the shaft. would like to find a resource similar to mitchel/shop key but for my mercury outboard so i can finish going through the lower unit in confidence things are right and not how i presume them to be using my instinct as a auto mechanic. serial on the motor is 1758349

 

[JWH0420]

Re: 100 HP Merc I6 Lower Unit questions

have tried clamping input shaft in vice and using a board to hit case away from shaft to get shaft free no such luck is there a separator tool for removing the shaft

 

[Gomer50]

Re: 100 HP Merc I6 Lower Unit questions

Thats how I did it.It works.In the late /early 60's they used a ball bearing which is pressed onto the driveshaft.In the 70's on up they began using the tappered roller bearing which made it alot easier to pull the driveshaft.Patience and use wood so not to damage the housing. (bigger hammer)

 

[JWH0420]

Re: 100 HP Merc I6 Lower Unit questions

well got a bigger hammer and a better board and gave it what for, took a few blows but it came out. couple other questions i have now one would be this ball bearing on the shaft it was pressed into the case and is between a shoulder on the shaft which would be below it and a snap ring above it you said it was pressed onto the shaft but it was free on the shaft between the two points there isnt much clearance and second i also noticed with the forward gear and "pinion" gear (pardon the automotive term) if i lifted on the input shaft it rotated smoothly but if i let the weight of the shaft rest downward when i rotated the shaft it felt a little rough as in gear mesh incorrect and the pinion gear needed re-shimmed under the ball bearing to correct it but i had the thought of maybe with the reverse gear in would it affect this and is ok riding on the two gut says no it should be corrected verticaly with shims regardless. looking close at the ball bearing there is a small amount of clearance in the snap ring groove for a thicker snap ring which would probably fix the lash on the pinion but not sure if that is a ok repair instead of trying to guestimate shims on a pressed bearing

 

[Gomer50]

Re: 100 HP Merc I6 Lower Unit questions

I hope you have a manual,in the manual it tells you how much play is acceptable and shimming.I am surprised that there werent any shimms under the bearing.This is a bit touchy the pinion gear,forward gear,and reverse need to sit just right to prevent as you said binding/not running smooth. Causing the gears to wear uneven possible distruction.

 

[JWH0420]

Re: 100 HP Merc I6 Lower Unit questions

there were shims present already and examining the gears the wear marks are middle of the teeth like they are sposed to be currently im debating how far i wanna go with this lower unit wether im gonna reseal it and leave the rest alone or if i wanna throw bearings in and go for the better build dont have any major bearing issues but the reverse gear bearing sounds a lil rough. as far as manual would a clymer have the kinda details im asking or is there a better option for such info personaly in automotive experience some of my questions if they were about a car wouldnt be in manuals kinda need a guy whos been there done that to opinionate like the thicker snap ring to tweak pinion depth

 

[carholme]

Re: 100 HP Merc I6 Lower Unit questions

420;

Your s/n comes up as:

100 1000 6-cyl 1755459 2318585 1965 USA

From here:

http://www.marinshopen.se/Motorer/O...cury2taktR66cyl80150hp/tabid/489/Default.aspx

Here is a condensed version of a Clymer service manual which may help you. Give the page 30 seconds to load.

http://web.ebscohost.com/serrc/pdf?...2-a482-b02133b62972@sessionmgr11&vid=4&hid=14

If you don't have visible wear on the gears and you recorded the prop gear lash before dis-assembly, you are probably in a good position and can change any questionable bearings. Even without recording the previous gearlash, you sound like you know what you are doing and with machine blue, you will know how to re-shim and know when you have a good gear pattern. As far as the circlip is concerned, I would just order a new one and keep the new and used one until you are ready to re-assemble. With the new one you can measure against the old one and see if someone has just thrown one in that worked but was not the correct thickness. If it is just a worn inset for the circlip, you may be able to use both circlips as a filler for the gap, if neccessary.

Here is the parts list for your engine if you don't have it.

http://www.boats.net/parts/search/Merc2/Mercury/1000/1464949 THRU 1768403/parts.html

Gerry