[tomtucker]

The last time I ran it, it jumped out of forward gear shortly after reaching one third speed. I throtled down and and it returned to forward gear and the same thing kept repeating. I remembered that the wrong oil had been put in the lower unit and now I replaced it with type C. Will this correct the problem or is it more likely an electric problem? What does go wrong when the incorect oil is used in the lower unit for one half hour?

[F_R]

That motor has the electric spring clutches and yes the wrong oil can cause slippage. So can water in the oil. So can a worn clutch hub and spring. So can a bad clutch coil. So can low voltage from the shift switch. And it might not be the shift at all, but a slipping prop hub.

Before jumping to conclusions and blaming the lower unit, ALWAYS check out the electrical system first. With the key turned on and the control in forward gear you should have 12V on the green wire going down to the lower unit (it's at the rear of the powerhead). The wires should be connected while making this test. Shift the control back and forth a bunch of times to make sure the voltage is there every time.

Then check the reverse at the blue wire the same way, except control in reverse.

Then disconnect the wires and do a resistance test between the gearcase wires and ground. It should be about 8 ohms.

Then check the prop for slipping.

Only if all the above is OK should you be concerned about the lower unit.