Mark 55 lower lube question

[hohnstadt]

Just purchased 1957 Mercury Mark 55 short shaft. It ran great (as previous owner said it would) on my test run of it. Today I wanted to check the lower lube to see if any water got in. I removed what thought to be the vent hole (6" above the prop level) and a few drops of water came out - nothing else. I then removed the drain plug (just under the prop level at front of lower unit), and nothing came out. Prev owner said he always took it to a marine place to have lubed so he was no help, and his marine place has moved. <br /><br />Am I looking in right place (both screws had wide heads, short threads, definitely plugs of some sort)? Should oil come out or does this unit use something else? I inserted small screwdriver in drain hole until it touched something, and pulled it out. It had something the consistency of grease on it - white and black. Do some motors (or marine mechanics) use grease instead of oil? I have a manual on order from OldMerc but in the meantime, any assistance would be appreciated.

 

[greasemonkeyozi]

Re: Mark 55 lower lube question

YES YES YES There is suppose to be lower unit 80/90 wt inside thet lower unit. Either those mechanics didnt put oil back into that unit, or you have an oil leak.<br /> To reverify the locations of your plugs, one is on the very bottom, and one is on the top of the unit. They are small and identical.<br /> Put some oil back into the unit and run it one more time on the lake. Drain the oil afterwards and see if its the same color it was when you first put it in. If its a milky color, you have a leak. DONT RUN IT WITHOUT LUBE... Thank god it aint damaged.<br /> I have a small leak in mine, so I always change mine out in every 6-8 tanks of fuel.

 

[corm]

Re: Mark 55 lower lube question

That motor uses 105 LU grease. It is white. If your seals are good you can use 90 wt LU oil. I usuall use 105 in them because the seal surfaces are pitted on most all of these motors by now. The bottom plug is a bit larger like a 1/4 in screw,well it's a bit bigger The upper screw is below the cavation plate on the trialing edge of the lower unit. It is much smaller. the large screw 9bigger than the bottom one) above the cavation plate is you waterpump flush plug leave it in.

 

[hohnstadt]

Re: Mark 55 lower lube question

Thank you both for your replies. The white 105 grease makes sense with what I saw, and explains why the motor has been running fine "without oil" - I'll have to find some of that. And thanks for the correction on the vent hole location - I sure have some manual studying to do, once it arrives!