They say BOAT stands for Bring Out Another Thousand, and it sure feels like that some days.
I fired up the boat this spring to perhaps get it ready to go out on a lake. I primed the motor with the fuel bulb and advanced the throttle slightly and turned the key. It took about 15 seconds before it started to make a little smoke and then it lit. It ran a little rough as it burned out the winterizing oil.
A short while later, the motor started beeping. I went over to it to check, and noticed no water was coming out of the “telltale”. That’s a problem. That’s a big problem. No water out of the telltale means no cooling water in the engine block.
You see, an outboard boat’s engine is cooled with whatever water it happens to be in. There is no independent closed-loop cooling system, like in a car or truck. It uses whatever it can slurp up into the intake and through the water pump. It dumps the hot water back out.
I promptly shut the motor down to keep it from burning out. Destroying this motor would reduce this boat’s value by at least half. Honestly, if I destroy this motor, the boat goes to the dump. I might be able to part some of motor out, but really that’s more effort than I care to take on. It becomes a “free project boat” for somebody, or right into a dumpster.
I let it cool a bit and tried it again. It ran great, but still no water showing up from the telltale. I mean, it ran GREAT!. Nice idle. Smooth. However, the beeping was a cry for help.
The most likely cause was a faulty water pump. The water pump on an outboard is an expendable part. It is something you replace every 3 – 5 years as a part of owning the boat. The core of it is a rubber impeller connected to the main vertical drive shaft of the engine. This rubber will degrade over time, especially if run without a source of water to cool and lubricate it. I really should have replaced it when I bought the boat. Oh well, live and learn. The next boat will get a new pump impeller right away, or at least an inspection.
I ordered a new pump kit off of Amazon for less than $50.00. Mercury Marine still makes a near universal water pump kit for their outboards. They used the exact same pump across many models and over decades of production. I don’t mind aftermarket, but it is nice to get OEM.
The pump came in, and then…Pandemic. I had to change my focus to protecting my family. The very early days of COVID-19 were filled with a whole lot of unknowns. People often panic when they feel they are in danger . Panicked people can be unpredictable. It no longer felt like a good idea to work on the boat and a better idea to go buy some TP, and non-perishable groceries. The freezer needed to get filled. Then we could hunker down at home and see what happened.
A couple of weeks later the kids had to be schooled at home. My workday stretched out from a solid 8 hours, to 10 or more hours, as I had to step away from my work-at-home desk to take care of kid stuff. The weekend became time to do everything we couldn’t do during the week. There wasn’t time to work on the boat, or any other hobby. Even if I could get things fixed, I wouldn’t have the time to spend to enjoy running on the water.
Just vrooming it in the yard has limited appeal. Don’t get me wrong, I like to hear it run after the work I put into it, but still.
Last week, my wife was musing how much fun it would be to take it out, and how much she enjoys being on the water. Well, that gave me a little encouragement to find some time to work on it. With schoolwork lessening, and a bit of the craziness going away, I was finally able to spend a little time on the boat. I figured that once the boat was running again, the act boating is being socially distant from others. It’s kind of built-in.
So, how does one go about replacing a water pump on a Mercury Inline 6 Tower of Power? Here we go.
The first step was good old YouTube. There are two guys I’ve followed for guidance on working on this thing.
The first is MerCSon L6, who spends a whole lot of time on them.
The second is cturboaddict, who gets into all sorts of mechanical things. One of his projects was an older 1976 model.
With guides like this, how hard could it be? Undo some bolts to drop the lower, and then swap out the pump! Of course it wasn’t going to be that easy.
I already had the replacement parts, and it looked like maybe this would be an hour or two job, so I started on it on a Saturday evening. The lawn was mowed and the kids were in generally good humor. I could spend the time on this. I set a goal of at least getting the lower unit off the boat and, if there was time, get the pump replaced. I’d put it back together the next day.
There is a lag between when you watch a video and when you do the work. You forget stuff. I undid the major nuts on the side and couldn’t figure out why it wasn’t separating out. I forgot I had to take off the zinc anode that sits right above the prop. To take off the anode, I had to remove the hydrofoils.
Under the anode were two more nuts and a bolt to remove. Those came out easily.
It still didn’t come loose. What the heck? I got a rubber mallet and whacked on it a bit. Nope. Ok, time to stop and take a good look at it. There was one more nut right in front and on top. Oops. As I backed that one off, the lower started to drop off the upper. Success!
Then it hung up. How could it hang up? There wasn’t anything more holding it on! But there was. The speedometer tube was still connected. I had to lower the motor down a bit to support it since the speedo tube required two hands to disconnect. Still the lower wanted to twist this way and that. It was rotating on the drive shaft. It must have looked pretty funny to see me holding things together with my shins as I bent over to take things apart.
Once the speedo tube was disconnected, I used a clamp to try to hold things together so I could raise the engine to get the lower out of the bottom of the upper. The driveshaft is about 20″ up through the bottom of the upper to connect to the splines on the crank shaft.
I held on to the lower with one hand and released the clamp with the other. I quickly grabbed it with my now free hand and it slid right out. I carefully put it on the ground next to the boat.
The lack of water cause was immediately noticeable. The tube that connects the pump to the water line that feeds the engine was cracked in two places. It could be that it cracked when I took things apart. Maybe it had water in it when it froze? Who knows? Good news is the kit comes with a replacement.
That was it for the day. Daylight was fading away and the rebuild would have to be the next day.
Sunday met us with the threat of rain. It was also Mother’s Day, with the associated maternal festivities. The rain held off and the radar looked pretty good. My wife and the kids went for a bike ride, so I took the time to finish up the boat.
The pump itself came apart easily. The first part is my most favorite named part, the centrifugal slinger. It is a little rubber ring that helps to keep water away from the pump, and what is below the pump (oil and water seals).
The rebuild went easy. I replaced the gaskets I could get to without taking it too far apart. There was a stack of 3 just under the cap that holds the impeller. This stack includes two gaskets and a plate to redirect the water. This plate, the impeller, and the impeller housing make up the water pump.
The YouTube videos above used some oil or grease to get the impeller into the case. I used some silicon rubber-safe lube, as I didn’t want to put anything in there that might eat the rubber. Various people on various forums have said that you can use really anything to get the impeller into the case. Oil, boat grease, silicon lube, motor oil, and KY jelly were all proposed. Most everybody said that whatever was used would get washed away pretty quickly by running the motor. It really didn’t matter what you used. I had the silicon lube, so I used it.
The impeller was a bit of a chore to get in, but eventually it did. I had to compare it with old one to make sure I had things pointing in the right direction, which it was. Thank goodness.
I was doing the work on the tailgate of my truck, as every shade tree boat mechanic ought to. The family came back just as I got everything fastened back together. Time to put it back on the boat!
Suddenly my sunlight was gone. I don’t mean just kind of fading out, but it was getting dark! I looked up and was greeted by some ominous clouds. The rain was coming, and it was coming fast. No wonder the family came home!
The lower got put into the garage in a rush. I went back out to get my tools and gathered everything up in my arms. I just made it into the garage when the sky opened up. Well, I guess the day’s boat work was done!
We all went in for dinner and the rain quit about as fast as it showed up. I figured I could get the lower put back with about a half hour’s worth of work. The sun was back out and I figured I had at least an hour.
One of the videos above mentioned putting the boat into forward gear before taking it apart. I didn’t do that. I missed it. MerCSon also mentioned that he prefers to just do it in neutral. Well…that’s what I was going to do.
He used a ratchet strap to help bring things together. I have a few, so I was going to do it that way too. I looped around the prop and up to the “handles” on the back of the motor. That helped to hold it in place as I tried to line things up. First thing, I put the speedo tube up through a hole in the upper. You know, just reversing my steps.
Next I lined up the water tube, and brought things together. Then the drive shaft splines lined up and slid together. Then, it didn’t fit. It kept getting hung up. What could it be? I looked. Oh…in my haste I had put the speedo tube up through the front stud hole. Now what to do? I had the lower suspended by a ratchet strap and things starting to come together. If I took the strap off, I’d have to start over to line things up. How to get a little wiggle room?
Well, I had a second ratchet strap and I set it up a little bit longer. One end on the little fin (skeg) on the bottom of the lower, and the other on the back handle. I took the tension off the first strap. The second strap promptly fell off and the lower slid uncontrolled out on to the ground. I may have said a bad word. Or two.
Thankfully nothing was damaged but my pride. I replaced the first strap to hold things together and rerouted the speedo tube into its proper hole. Ok, now line up the water tube….line up the drive shaft….line up the shifter linkage….tighten things up….and….stuck.
Again, it won’t budge. I double checked everything one more time. The shifter linkage is a splined shaft on the lower that fits into a splined tube on the upper (look at the photos, it sits in front of the driveshaft). It didn’t stay lined up and the shaft was impacting the side of the tube. These things were now under tension from the ratchet strap, and I didn’t want to bend anything to force them together. I’d have to remove the strap again to take the pressure off.
This time, instead of a second strap, I placed some concrete blocks under the lower and set it down on them. Just barely touching. Then I raised it just a tiny bit. It was enough that it didn’t move much when I undid the strap. This was much smarter than last time. See, I can learn new things!
I carefully started tightening the ratchet strap again, and brought things together. This time the water tube was good, the drive shaft stayed connected and I was able to contort my hand just enough to get the shifter shaft into the the splined tube. It all came together as I continued to ratchet it up. The upper and the lower met once again.
The last part of assembly was to get the nuts back on. There is a small issue, though. The nuts on the side need to go on as things are brought together. There isn’t room for them if the lower is fully seated with the upper. I had to use the concrete block trick again to just get enough room to get the nuts on the studs, and not allow everything else to come apart. It worked!
Now the moment of truth. Will it pump water? Will it shift into forward and reverse? Did I totally mess it up? Chances were high that it was messed up and I’d have to do it over again.
I put the “ears” on it and turned on the garden hose to feed water to the intakes. The motor started with just a few cranks and, once again, sounded great. I waited…will it pee? I would be so happy if it did. Still nothing! NO WATER OUT THE TELLTALE! Oh no, all that work for nothing. I reached over to turn it off and glanced back at the motor. It was peeing. It was a nice little stream of water out the telltale. I was relieved. I was a little giddy, really.
A shift into forward had the prop spinning forward. A shift to reverse, and the prop spun backwards. Wow! You mean I actually did this thing correctly? Wonderful!
The air was starting to get cool with the evening setting in. I let it run a bit just to make sure everything was solid. The water coming out of the motor started steaming on the grass, but it never set off the heat alarm. I figured it was good and shut everything down.
I put my tools away. The boat is ready once again.
For now… After all, it is a 30 year old boat. Something else is bound to break.