[bmk88]

i have a 1971 100hp evinrude with selectric lower unit. it shifts fine but when under full throttle and turning real sharp it kicks back to neutral until i straighten out and idle it down a bit, then its fine again. What could cause this? thanks mike

[tashasdaddy]

check you oil level, when was it last changed, remember only Type C Premium Blender oil in lower unit. also could be clutch dog going.

[bmk88]

i just changed the oil with type c from my local dealer and it is full. You say the clutch dog? is there a way to test it? thanks mike

[F_R]

If the trouble you are describing is the only time it acts up, it doesn't sound like any kind of motor trouble. Call it cavitation, ventilation, blow-out, or whatever you choose, but it is getting an air bubble around the propeller under extreme manouvers. You can live with it or spend big time and bucks trying to prevent it, or quit hot-rodding it.

[bmk88]

this motor is on a 1965 16' glasspar. At full throttle it only goes 25-28 mph. the lower unit will stay in forward if im doing 20mph or under. we use it for tubing and fun stuff. if i cant take a hard corner at 25 mph without the lower unit shifting to neutral there is a problem. I dont believe it is cativation because the motor rpm revs high when it shifts to neutral. I wish i had a manual lower unit. mike

[larky]

I think F_R hit the nail on the head. Its either cavitation, or a slipping prop hub (though I doubt it by what you describe). two things to try. 1. move the tilt pin in one hole. 2. drop the the outboard mounting bracket down on the transom more (that is, if it has been lifted).

[R.Johnson]

That engine defaults to forward gear, it cannot come out of forward except by hydraulic force to the clutch dog. Low oil, or no oil will damage the internal parts, but it will not make it shift out of forward. You have to activate the solinoid by electric signal, to change the valveing in the hydraulic pump to shift that engine to neautral, or reverse.

[F_R]

Exactly. It is always in forward unless you make it come out of forward by pushing the button. OR, if the clutch dog is worn it can pop in and out of gear just like a manual one. However, because of how they are constructed, it is extremely rare to find a worn forward clutch dog in a Hydro-Electric. Anyhoo, worn clutch dogs jump at any time when under load, not just in a turn. And they immediatly slam back into gear with a bang, not wait for you to slow down.

I will admit you could have a spun prop hub, but doubt it so much that I didn't mention it.

[bmk88]

how could i tell if the prop hub has spun? any other ideas?