No reverse gear

westy66

Cadet
Joined
Jun 19, 2012
Messages
11
i changed the impeller last week and put everything back together and took the boat out for a spin.... almost couldnt even get out of the launch i had no reverse :facepalm: i have forward and neutral.

ive read at least 20 threads about this happening to people, but none of them quite make sense. when i did the job, i had it in neutral. i dropped the LU and moved the little cam to another position and still no reverse. i dont know what else to turn or rotate. i need some help like a picture.

can someone assist. im gong nuts....

thank you!
Bob
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: No reverse gear

Bob;

Read your previous posts but cannot figure out which engine you are referring to. What is the s/n and hp of the engine?

You will have to drop the LU again and if it is an early s/n both the boat controls and the LU must be in Fwd gear for re-installation. If it is a later s/n, both must be in Neutral.

With the LU removed, you determine which gear you are in as follows:

Using finger pressure only on the prop

Forward: Prop will rotate (ratchet) CW but not CCW
Neutral: Prop will rotate freely in either direction
Reverse: Prop will not rotate in either direction except for a few degrees of gear mesh

Now that you know what gear the LU will be in and based on your s/n, you can set the boat controls and LU to that gear.

You must also have the shift cam installed in the correct position on the LU splines before installing the LU or you will not get reverse and be able to engage the reverse locking pawls.

Do you have a manual?

Gerry
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: No reverse gear

if it is an early s/n both the boat controls and the LU must be in Fwd gear for re-installation. If it is a later s/n, both must be in Neutral.

Gerry,

This is confusing to me. Since when "must" one select one or the other? I have done it both ways depending upon the size of the engine and which was the most convenient and I wasn't careful about what year it was. If you are referring to an early sn as being in the '60's or prior then maybe so. I was an OMC guy then and left the badge for Merc in the late 70's so that is as far back as my association has been.

Seems to me his problem is that he either moved the shift lever or the twisted the shifter shaft in his repair effort getting his cam lined up with only 2 of the 3 options he needed. As soon as he drops his LU you gave him the answer and his problem should be obvious.

Mark
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: No reverse gear

The earlier engines had the two piece metal cams while the newer ones had the single piece composite cam. However, you do it the way you want, this guy is asking for help and it seems appropriate to give him what the manual says.

This is based on his previous posts, presuming that the engine he is referring to is a 1978 70hp. 3 cyl.

Before attaching gearcase housing to
the driveshafthousing,make certain
that shift cam (7-Fig .Mll-40) and the
shift lever (onmotor) are in forward
gear position on models with reverse
locking cam shown in Fig.Mll-42 and
neutral position on models with reverse
locking cam shown inFig.Ml1-43 .

Gerry
 

westy66

Cadet
Joined
Jun 19, 2012
Messages
11
Re: No reverse gear

Thank you. I do have a 1978 70hp 3 cyl with the composite shift cam. So, if I'm understanding you correctly the position of that cam is my problem? There is a little wear on the 'ramp-ed' portion of the cam but I don't think enough to not engage. I have a Clymer manual but don't see that cam addressed anywhere.

The cam appears to have 3 positions. I put the control in F, dropped the LU and put the cam in the forward pointing position. It appeared that the prop spun just as you described, but still no reverse. That prompted my post.

So if I drop the LU again with the control in F, what position should the cam be in? 12:00? 3:00? (where front is front of the boat)

Thank you so much
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: No reverse gear

The cam is designed to lock the engine in reverse and neutral, that is, the rod is sitting on the flat surface of the cam. When you select Forward, the rod slides down the ramp.

Here is a link to the condensed version of the Clymer manual and you will see the composite cam in figure M11-43 on page 250. The old style two piece is in figure M11-42.

http://web.ebscohost.com/serrc/pdf?...5-8e0e-3318bbcbc560@sessionmgr11&vid=4&hid=15

Download soonest to your computer as the link is short lived.

Gerry
 

JUSMARCEL

Cadet
Joined
Jan 31, 2012
Messages
23
Re: No reverse gear

Commander carholme is correct i have that same motor only an 1981. Best added advice i can give is to get a second pair of hands to wiggle flywheel as you are down looking at yur shaft as you proceed. i have been where you are and it is not an easy job. best of luck. marcel
 
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