Breaking the lower unit shifter on 1988 70HP ETLG

[wakilgore]

I have a 1988 70 HP ETLG. After years of great running i had problems with the motor not shifting. One day it would not go into forward. Pulled lower unit found the shift slightly cracked at the neck. Rebuilt the lower unit, new seals, carrier bearing and a new cam and shifter. All went well, forward and rev (followed than manual). Putted around, shifted back and forth. All worked great. Went to increase RPMS started up then it appeared to slip out of gear before reaching a plane. Would still go in reverse. After several minutes would not go into for. or rev. Took it all apart, found the neck of the shifter broken off. Bough another new shifter, re-installed. Same thing again. All was good until I started to increase RPMS. Took it all apart and found again a a broken shifter. have been told there is a redesign on this lower unit with a clutch dog with more tangs. What am I missing? Am I not torquing everything together and under load the the clutch dog slips aft breaking the shifter? Help.

[Bilge Rat]

Check the shifter cable adjustment and for freedom of movement.
Check all clearences in the LU.

Breaking the same part 3 times, you are missing something that is the cause.

[wakilgore]

Have checked the shifter cables. All is aligned. Is it possible for the clutch dog to be slipping off under load (as I increase RPMs). I have a hard time verifying the clearances. Is there a simple check?

[rodbolt17]

its possible that the clutch dogs are simply worn out and that's what broke the first part.
once the dogs wear they cease to lock together and will act like a screw thread and force itself apart under a load.

I would carefully inspect the clutch and gear dogs for wear.

[wakilgore]

Can you describe what I need to look for in a worn clutch dog (or picture). The tabs (?) for rev or forward look the same. The gears tabs look great.

[rodbolt17]

no pics.
what your looking at is the engagement surfaces.
are the corners nice and sharp or are they rounded.
rounded is bad.

I had one of those necks break on my dyno some years back at about 4800 RPM.
went to N under load on the dyno.
don't know what kind of RPM that 70 turned but it was rather scary.

[wakilgore]

Thanks, you are right the edges are not sharp, very rounded in the Fwd section. Because it is hardened I will assume grinding is not the answer. So purchase a new clutch dog. Do I assume gears?

[rodbolt17]

typically if the clutch is rounded that gear is also rounded.

[wakilgore]

Thanks for the help!