Hello,
I am quite a novice when it comes to boat motors. I ran my new to me motor, and think I may have an issue. Am I supposed to have water coming from these two holes (see picture attached). I have it hooked up to the water intake, but water only comes out below, not out the water pump holes. Is there any way I can check to see if the water pump is or is not any good whithout disasembly? Also, how do I check to see what year my motor is for sure? Thanks, Steve
Are you sure it's two holes and not just one that would be on the starboard (drivers) side of the motor? I've never seen a Merc with two holes. If you're talking about the two square shaped holes, those are for exhaust. A little bit of water does come out of them though which is normal. I used to have to take a 12GA. electric wire and poke it up through the "pee" hole to remove the little clogs after each season. Give that a try. If that does the trick, then your water manifold is just a little filled with lake gunk from years of use.
I would pull the lower unit off - don't panic - it's quite easy. Just remember to NOT TURN THE SHAFT and the realignment would be a snap. Take a black marker and mark the shaft and the top of the impeller (water pump) housing which is right on top after the lower unit is pulled. This is to line up the shaft in case it is turned. Then remove the screws and gently pry off the top. You'll see the impeller and it's condition. You might as well go ahead and get a new one to install while you are in there - why not? But this would answer your question if the water pump is functioning to its capacity. If the shaft has turned, then realign it by turning it clockwise only to keep the impeller fingers turned the right way.
Oh yeah... on the year - there should be an ID plate fastened to the front of the motor clamp bracket just under the steering rod. There, you'll find the VIN number and you can call a Mercury dealer and have them verify the year for you.
Steve, Most of the cooling water should come out the grating above and behind the prop. Some will come out the prop hub. The two square holes high up on the midsection are exhaust relief for lowering back pressure, when the motor is in neutral and running in the water. Some water could come out of these when running on the muffs, but it also may not spit, which is normal. Older Inline Mercs do not have thermostats, so the cooling water should be lukewarm at most, running on the flusher in neutral. If the water is warmer than that, the water pump is bad.
If you do not know when the impeller was changed last, you probably should change it now.
Hey guys, thanks for all the help! I cannot get it to spray any water, so I am going to pull the lower unit. I still have a question though about how to take off the lower unit. How does the rearward section right above the propeller come off. It has a little hole above a moveable round fin, but I cannot see anything to disconect it. I have seen these before with a bolt in them, but the hole is two small on this old of a motor (1967) to be able to get any socket in there, and it does not seem to have any screw of any type. If you have any ideas I would greatly appreciate them. Thanks, Steve
Older mercury motor water pump issues
Linear Mode
