Re: Mercury 78A? Anyone know anything about it?
Frankly, i'm a bit worried about starting it up.. I found a thread on another forum that had quite a bit of information (more for boat engine tech-heads) and this engine seems complicated as hell.
I drive old vehicles because they're so much simpler and easier to fix, doesn't seem to be that way for this old engine.
I can't wrap my mind around the way it works.
My throttle lever looks like one from a typical boat, push it forward or pull it back.. but on this forum they're talking about a Z shaped control box that has different switches to start the motor in reverse/forward rotation.
Then to add to all of my confusion, I pulled plugs from the lower section to fill/check oil and it's packed full of thick grease? I only vaugely remember how to do it on my old boat. The top plug was labled 'flush', there was a much smaller one between them with no lable, no idea what that is. I'm scared to even try to dry-crank the motor because of the stupid grease. I couldn't get any oil through either hole, it's really packed in there.
I can't find the water pump inlet either.
It's a shame, this motor looks like it's in really good condition. there is a tiny bit of wear on the lower unit (nothing serious, I've seen 00's with more nicks), the motor has been spraypainted black but otherwise it looks nice, especially inside the cover.
Maybe I'll put up some pictures tomorrow
First, the distributor rotates a full 180 degrees. That means the motor itself can run forward or backward. Odd I know, but that's how it works. The "shifter" should like like the image below.
The water pump inlet is below the anti-cavitation plate directly above the propeller.
The 78 typically came in "Cloud White" or "Sunset Orange."
A good indication of the state of your outboard would be to "hand crank" the flywheel. Take the top cowl cover off (removing six nuts and removing a clamp to the choke knob) and grasp the flywheel. If you can turn it without too much effort you are also turning the crankshaft and pumping the pistons through their range of motion.
According to my shop manual only two screws are involved when adding gear lube. The instructions say;
"1. Remove the lubricant filler plug, located on the right side of the gear housing just above the skeg, then remove the air vent screw above the anti-cavitation plate, being careful not to lose the associated washers. IMPORTANT: Never apply lubricant to the lower unit without first removing the air vent screw, as the injected lubricant displaces air which must be allowed to escape, otherwise the gear housing cannot be completely filled as required.
2. Insert lubricant tube into filler plug hole and inject lubricant until excess fluid starts to flow out of the air vent screw hole, indicating that the housing is filled."
3. Replace air vent screw first, then filler plug, taking special care that the washer is in place under the head of each screw so that water will not leak past the threads into the gear housing."
