Checking and changing the lower unit oil on a 62 Merc 800 80hp

[oldmerc80]

How would I go about checking the oil in the lower unit of my 80hp Merc? There is a drain plug on the side of the lower unit. What color is the oil supposed to be? If I were to replace it, what kind of oil and how much would be required? I have read mixed reviews on the 62 Merc 800 Stick shift. Can you give me some honest opinions about your experiences with this engine.

 

[wippb]

Re: Checking and changing the lower unit oil on a 62 Merc 800 80hp

Hi Oldmerc<br />I don't know anything about your engine and I know that this Oil Change isn't the motor that you have but it gives a pretty detailed desciption of how to change the oil. It should be the colour of light to dark molasses. It should not be coffee with cream coloured. That indicates there is water getting into the gear case. Use a good quality marine grade gear oil. It is designed to emulsify with water if water is present and gives you that coffee/cream colour. Check for metal debris when you remove the bottom plug. Tiny glittery pieces are okay. These flakes indicate normal wear. Chunks are bad.<br /><br />Just My $.02 worth <br />Good luck

 

[skier]

Re: Checking and changing the lower unit oil on a 62 Merc 800 80hp

Hi Oldmerc80<br /><br />There are two plugs on the lower unit, one is a drain and the other is a vent. Whipper is correct about the color. Use "Quicksilver" Gear Lube. It comes in soft tubes. One should do it for your motor but get two just in case. To drain the oil take the drain plug out and then the vent plug and tilt the engine so that the drain hole is at the lowest possible point. After drainned, replace the vent plug. To fill return motor to zero tilt position, cut the tip of the soft tube and stick it in the drain hole, whith the tube firmly in tht drain hole unscrew the vent plug (But not completely) and squeeze the tube. Stop when oil starts comming out the vent hole (This might take more than one tube of oil but I doubt it, My 140hp takes two and it's a big gear case). Tighten the vent screw and remove the tube from the drain hole. loosen the vent screw and let approx 1/8 - 1/4 inch drain out of the gear case then tighten the vent plug and replace the drain plug. This allows for heat expansion.<br /><br />Hope this helps and good luck