ZF Gear: No Oil Pressure

[racclarkson@gmail.com]

You have manual with the fluid flow diagram? Post it

I do and I don’t. It’s a little bit on a page and more on another page. I have owners manual and parts manual. May have to spring for a service manual. Had to send to the Fatherland for the parts manual. Now I’m studying German so I can use it. Verstehen sie?

[racclarkson@gmail.com]

Got about the best news possible outside of a miracle.

Took the boat out today, single engine. As hoped, the port prop freewheeled and made 175 psi of oil (normal) pressure from the output pump at about 6 kts. So, with the port gear lubricating, I cranked the port motor. I was able to slip it into gear easily. The momentum of the spinning prop overcame the pressure drop from the shift and I was able to freely shift gears at will. There was no unusual vibration or noises indicating any internal issues. All was well until I slowed near the dock. There the pressure began to fall off, so I took it out of gear and shutdown the engine.

Therefore, the problem is narrowed to a bad input oil pump or it's drive. The next step will be to drain the gear. Then I will be able to remove some of the piping and visually inspect to determine if the pump turns when the motor is turned over.

Of all the possible scenarios, this is the one to have.

[Dan Mapes]

Is there a separate regulator for each pump or only one? There is virtually nothing to an oil pump so I am wondering if the shaft to it snapped or a key popped. Maybe a check valve(s) between the pumps?

[racclarkson@gmail.com]

Is there a separate regulator for each pump or only one? There is virtually nothing to an oil pump so I am wondering if the shaft to it snapped or a key popped. Maybe a check valve(s) between the pumps?

Nope. My bet is shaft. Going to drain it in a few days and start pulling. Taken a good day with paint remover and PB.

[Dan Mapes]

I guess keeping an eye out for something that would jam the pump would be a good idea. Good luck.

[racclarkson@gmail.com]

Yep. By the time I’m done with this I’ll be a certified ZF specialist or maybe just certified.