Early Merc pwr. Trim/tilt

[hereto]

I have a 1976 Mercury 85hp with the early model pwr trim/ tilt, two cylinders and pump mounted in boat. I checked the oil level in the pump and saw that it was correct, but the oil looked very dirty (black). I have two manuals, Clymer and Selco , neither makes any mention as to changing the oil in the pump. I checked the explode pump dwg. And there is no mention of a drain screw.
My trim/tilt unit works Perfectly with no problems of any kind, it just appears to need an oil change. Have had this guy for about 6 mos and have no idea if the oil has ever been changed, or for that matter if it should be changed. If it should be changed, I?m hoping some one can walk me thru it such as where is the drain plug and what things to do and NOT to do. Once again, appreciate the help.

Hereto

 

[Moody Blue]

Re: Early Merc pwr. Trim/tilt

Can't say for sure if/when the oil needs to be changed but I changed out my oil last summer. I removed one of the bleed screws on a cylinder and ran the pump till the oil was pumped out. Refilled my system with ATF fluid.

 

["G"]

Re: Early Merc pwr. Trim/tilt

Can't say for sure if/when the oil needs to be changed but I changed out my oil last summer. I removed one of the bleed screws on a cylinder and ran the pump till the oil was pumped out. Refilled my system with ATF fluid.

Yup... that works. Just be sure you work the up and down circuits to complete the change. Flushing with new oil is needed as well. Air is likely to get in the system if you don't.

 

[hereto]

Re: Early Merc pwr. Trim/tilt

Thanks Guys,
But just one more question about flushing the system with new oil to keep air out of system. Should I run out about half of the reservoir then add new oil, and continue to do this till the oil is clear, or maybe flush about 2 guarts of new oil thru it and them fill with new oil? Just want to make sure I understand about flushing the system. Thanks so much for your response and help.

hereto

 

[stinkbait85]

Re: Early Merc pwr. Trim/tilt

Do you have a wiring schematic on the tilt/trim unit? I have an awful mess of wires here and no idea where to start. I just bought this motor(85 mariner) 2 months ago. Please help.