Keep braking tilt shaft on 1977 OMC outdrive

I have a 1977 Crestliner 190 HP with a 302 Ford motor with an electric shift lower unit. I recently changed the tilt motor for my tilt system (1 year ago) as the 2 metal pins that go into the coupler on the motor itself broke and the motor was not working all the time. Since I changed the motor, I have now gone through 4 tilt shafts. The shaft only breaks (at the part that goes into coupler) when I push the tilt down button and the motor goes down all the way with a thump. I have since changed the solinoid and had the switches, tilt motor and coupler tested. All is good. I have been told by many mechanics that this is only happening because I hold the down button for more then a split second and I am causing the lower unit to go down too fast. They are right, as to say, if I just tap the button, the motor does not go down all the way and then tap again, it does not thump as hard or break the pin. But, sometimes it still dhas broke the shaft. When I had the old tilt motor I never had a shaft brake in 20 years. Why are they breaking so often now? Has anyone had a simular problem? Any suggestions on how to prevent this from happening so often?

Re: Keep braking tilt shaft on 1977 OMC outdrive

Maybe some binding inside the tilt gear box? ? ? I have broke one shaft like you are describing, but that was when I first had the boat and I didnt use the "tap never hold" the tilt switch method.

Isnt it the hammer blow couplers job to create the weak spot in the system so this doesnt happen and cause major damage? almost like a fuse? maybe look into that. Good luck

Re: Keep braking tilt shaft on 1977 OMC outdrive

Maybe now you've had it all apart it's moving more freely/faster and now has enough impact to break the shaft. Or possibly the newer shafts are a slightly weaker steel than the original? You are just going to have to be very careful when lowering the drive. "Tiny taps"! BTW, is the cap on the end of the worm gear housing held in with just a snap ring or does it have 3 bolts? If it's just the snap ring, slamming the drive down can blow that cap off the end and send it and the worm gear/shaft flying out and into the drink as some unfortunate i-boaters have found out in the past! I'm always very gentle lowering mine for just that reason. (at least 3-4 quick taps to lower it all the way)

RR: I think the hammer-blow coupler is just supposed to let the tilt motor shaft start to move before taking the load of moving the drive, to let the motor get a 'running start' as it were . Looking at the small 'ears' on the end of the shaft engaging the coupler I can see them breaking off as easily the coupling itself breaking.

Re: Keep braking tilt shaft on 1977 OMC outdrive

NW Redneck said:

BTW, is the cap on the end of the worm gear housing held in with just a snap ring or does it have 3 bolts? If it's just the snap ring, slamming the drive down can blow that cap off the end and send it and the worm gear/shaft flying out and into the drink as some unfortunate i-boaters have found out in the past! .

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Anyway, regarding the shaft that keeps breaking, is it an aftermarket "Made in China" part?

Re: Keep braking tilt shaft on 1977 OMC outdrive

NW Redneck said:

RR: I think the hammer-blow coupler is just supposed to let the tilt motor shaft start to move before taking the load of moving the drive, to let the motor get a 'running start' as it were . Looking at the small 'ears' on the end of the shaft engaging the coupler I can see them breaking off as easily the coupling itself breaking.

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Gotcha, that makes sense.