Lower unit repaired and now.... No reverse!....

C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
I have a late 80's Mercury 75hp 4cyl SN: A707172 I recently had the lower unit in to have the upper vent screw repaired, not sure if they messed something up or not..
but now I cannot find reverse,
I have forward: prop ratchets cw
neutral: prop spins free
reverse: (seems to be forward) prop ratchets cw

The LU is off on my bench

Any suggestions on what to look for???
thanks
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

K.. I am thinking to pull out the shift shaft, guessing something there is messed up, just guessing, What is involved with removing the shift shaft? do I have to do a complete tear down of the lower unit? or will the shaft come right out? Any special tools?
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Lower unit repaired and now.... No reverse!....

As you rotate the shift shaft you should 'feel' two positions, detents. All other positions are by default, in Forward gear. In one detent the shift slider is pushed back into Neutral, the other pushes farther back into Reverse.

If this gearcase had both gears before the repair it should just be a matter of installlling the gearcase while 'shifted' into one of the detents and having the shift control box shifted into the same position, i.e. Neutral.

If the gearcase did NOT or does not shift correctly a possible cause is a worn shift cam and/or shift cam follower worn such that the slide is not being pushed far enough back so as to fully lock into Reverse.
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

when I rotate the shift shaft from Neutral CW it falls into an indent (forward)...
Neutral does not have an indent (seems to be riding up on something (prop spins either direction freely) approx one tooth spline travel
when rotating from Neutral CCW the next indent should be reverse however the prop ratchets forward CW and locked the opposite way CCW (seems to be forward again)

Am I mistakenly assuming Neutral or????
 
T

turtles11756

Petty Officer 1st Class
Joined
Dec 5, 2007
Messages
260
Re: Lower unit repaired and now.... No reverse!....

i'm fooling with a shift shaft this morning could not find reverse. the motor (merc1000ss) when i bought it with lower unit installed would not shift into nuetral (stuck in foward). try pulling up on the shift shaft as you shift into reverse/ foward. all gears are there now but no telling if it will stay that way ?
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

Thanks...I've tried pretty much everything, cant seem to get the LU sync'd with the shifter, just had the LU serviced by a mechanic so I would think the unit is good. (as I cant feel an indent for reverse)
Could I have done some damage by rotating the shift shaft in either direction?
 
merc850

merc850

Commander
Joined
Jul 7, 2010
Messages
2,046
Re: Lower unit repaired and now.... No reverse!....

Try this:
Turn the LU shift shaft by hand counter-clockwise until it
stops, then with Vise Grips tight on the bottom of the shaft turn it a
few more degrees CCW until it clicks into a stop, this
should be neutral - check by turning propshaft --
do not shift into reverse unless you turn the propshaft at the same time.
If it is in N go ahead and attach LU to driveshaft housing with control in N.
I'll be doing this soon.
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

I rotate the shift shaft by hand ccw till it stops, turn it a few more degrees it clicks but seems to be forward (the prop ratchets forward CW and locked the opposite way)
a few more degrees ccw on the shift shaft is Neutral, it does not have an indent (seems to be riding up on something (prop spins either direction freely) approx one tooth spline travel
when rotating from Neutral CCW the next indent should be reverse however the prop ratchets forward CW and locked the opposite way CCW (seems to be forward again)
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Lower unit repaired and now.... No reverse!....

Worn cam and/or cam follower

Youo will need to pull the propshaft out and actually look at the cam follower and cam.

I suspect you will find the nose of the follower has worn so much that it is not long enough to 'push' the shift slide far enough back for Reverse.
 
MH Hawker

MH Hawker

Vice Admiral
Joined
Jul 13, 2011
Messages
5,516
Re: Lower unit repaired and now.... No reverse!....

I just spent 3 days correcting a skilled mechaics work on my lower unit.
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

looks like i'm going to be working on this for awhile, aside for the info I receive on here, (I know nothing, so thanks for the replies) I was told tonight that my lower unit is an "easy shift" (has a grease nipple at the rear below the prop shaft), As well I was told this is a difficult unit to work on... is this true???
 
C

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: Lower unit repaired and now.... No reverse!....

Your s/n is a Canadian built engine:

75 1986 ELO A197882 - B249479 A707086

From here:

http://www.maxrules.com/models/Merc_model_files/60-100.html

Parts listing:

http://www.crowleymarine.com/mercury-outboard/277.cfm

Service Manual P/N: 90-86134--4

Whoever told you that line of crap in your last post shouldn't have been working on it in the first place. When you had it in for service did they tell you if they had completely dismantled the LU to do the work. If so, it is probably worth your time to pull the bearing carrier and at least check the cam folllower and cam. Let me know if you do not have access to a manual and I will send you the condensed version of the Clymer manual which will be enough to do the job you need to do.

Gerry
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

Thanks Gerry I do not have a manual, I have been searching the net for one, greatly appreciated if you can send one my way, not sure if you attach a link within the post or just send it directly tsdavey@sympatico.ca

question though: after reading my post here; and with me not finding reverse, do you feel my problem relates to the shift cam/ follower? My gears including reverse worked fine before having the vent screw repaired
 
C

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: Lower unit repaired and now.... No reverse!....

The only thing I can think of is that they disassembled the LU and something has gone wrong, especially if it was working OK before. You shouldn't be having that much trouble getting reverse.

In this link, you will see item 70, the nut which holds the bearing carrier assy in place:

http://www.crowleymarine.com/mercury-outboard/parts/277_200.cfm

If you do take it apart, please note if it is loose when you start to unscrew it.

As you can see you will need to have the special tool to remove the nut or you can make one with a piece of pipe about a foot long. Cut four tangs in the end of the pipe to match the slots in the nut. With a hole drilled through the other end of the pipe, you can pass a rod/bar through that hole and be able to undo the nut.

Making any sense?

Here is the link to the condensed version of the service manual. Let the page load for several seconds and then download to your computer soonest as the link is short lived.

http://web.ebscohost.com/serrc/pdf?...8-8247-4d9b8824bde8@sessionmgr11&vid=4&hid=19

The lower end starts on page 284.

Gerry
 
MH Hawker

MH Hawker

Vice Admiral
Joined
Jul 13, 2011
Messages
5,516
Re: Lower unit repaired and now.... No reverse!....

If it was mine I would take it back and let them fix it. If all elese fails you can look into it.
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

Thanks Gerry, Greatly appreciated. will let you know how it goes...
As for taking it back, wish I could... however the marine and I parted unhappy as the original estimate to fix the vent screw was $200 more than originally quoted, I did split the extra cost with them but they weren't happy with me. I just wish I had checked the operation before I left the marine, all hind sight now..live and learn
 
C

Confuzed

Cadet
Joined
Jun 20, 2010
Messages
29
Re: Lower unit repaired and now.... No reverse!....

Just an update: Took the lower unit to another marine, (actual Mercury technician), he tore it down and found the 3 ball bearings at the front of the prop shaft weren't in it, "most likely why I had no reverse" I also noticed (after laying it down to take it to him) oil leaking out of it, Boy did I getted ripped from the original Mercury Marina, (I actually paid them to repair this at $105/hour).. As for now he has ordered the parts and is doing a complete reseal for me, Just hope the first marine reimburses my cost.
Want to say: Thanks to everyone who helped me along the way, If all works out I'm gonna stick with my new mechanic
Safe boating!!
 
You must log in or register to reply here.
Top