Early OMC Sterndrive problem

[rrmartnz]

Please excuse if I ramble, first time on this forum. I have 1977 Apollo 27 foot with I/O OMC 235 and 351 Ford engine. Because age of boat did full tune up, changed all fluids (have manual) spent many hours and trips to local OMC dealer (Rodesway in Glendora) before using boat.
Boat handled well inshore and offshore but after 10th outing lost forward gear while cruising at 17 knots. Reverse was fine and no apparent contact with anything in water prop fine. Had sterndrive checked by marine mechanic and found forward spring broken. He indicated high impact break. We never heard any noise when we lost forward just like someone put boat into idle, no one was adjusting speed when occured.
Anyway, had entire stern drive rebuilt with new springs and magnets etc $$$. Took boat again with advice by mechanic to make sure engine idle at 600 or less never shift until boat rpm low, we did all these things. After 5th trip on way to Catalina again at about 18 knots we lost forward gear again. No loud noises, no hits, nothing that indicated any problems. Sterndrive back to mechanic and once again forward spring broken in almost same spot as before. He replaced spring again at much reduced price but said will happen again if original problem not found. I checked control to make sure constant 12 volts going to drive seemed fine. The only constant is happened at relatively same speed. So boat is sitting we will not take out again and considered just getting rid of boat but don't feel right selling this problem to another boater. Any help would be greatly appreciated.

 

[WizeOne]

Re: Early OMC Sterndrive problem

I had the same problem with a 1975 electric shift. I had purchased the boat brand new and naturally after the warranty expired, the forward slinky started breaking. I think it did it about three different times. They alluded that it was due to a momentary loss of continuity in the electrical circuit which would cause the slinky to quickly disengage, then re-engage, under power. This of course would snap the engaging tip off the spring.

They never could find the problem so, by this time it was 1979, I installed the new hydro-mechanical outdrive. Never been happier and in all these years it never let me down.

I was forunate in that I was always on the lake when it broke and could return to the dock, in reverse gear.

 

[rrmartnz]

Re: Early OMC Sterndrive problem

Thanks that conversion sounds very interesting right about now. I will call around to get quotes. I was also told the control switch may be problem and if drop in 12 volt current to drive happens there goes slinky. I tested with key on and voltage seemed constant but with boat in water engine running, accessories being used ( have 100 amp alternator and 2000 watt inverter for frig and microwave) who knows maybe a power drop to control caused all this. I was seriously considering using some kind of direct toggle for forward and reverse to constant power source along with the control for acceleration. A new control switch in this area sells for about $ 500 and its a replacement type not original.

 

[bruceb58]

Re: Early OMC Sterndrive problem

yes...sound like an intermittant connection to me as well. would be interesting to have someone try to spin the prop while going around and wiggling wires while in forward gear.

 

[WizeOne]

Re: Early OMC Sterndrive problem

yes...sound like an intermittant connection to me as well. would be interesting to have someone try to spin the prop while going around and wiggling wires while in forward gear.

From my experience the only way you would catch it would be some kind of streaming recording device. They make things like that for cars. You hook it up and it records a string of parameters with a short memory function. When you have an incident, you hit a button and the unit retains all of the data from several seconds before you hit the button until several seconds after you hit it.

Then you display the retained data on a computer printout.