Hello… John Talley here with Boats.net.
Today we’re going to be taking a look at how to diagnose overheating problems in your outboard.
Specifically, I’m going to walk you through the cooling system on your motor so you’ll know
what to take a look at if you’re experiencing overheating issues. Now you’ll want to address
quickly because an overheated engine can lead to all sorts of problems downstream that can do a lot
of expensive damage inside your motor… and you don’t want that. So if you’re ready… let’s go.
Okay guys… every outboard is a little different… but basically the story is that water gets drawn
in from the lower unit… pushed up into and around the powerhead by the water pump…
and then pushed out of the motor. Now there’s five areas along the path the water will take through
your outboard where we might find our problem… The first two are really straightforward:
water in… and water out. Now let’s start with the water output…
some people call it a tell-tale… and it does just that. When you see water flowing out of it in a
steady stream while you’re running your boat… you know that at least water is flowing through the
cooling system. Keep an eye on that… especially if you don’t have a temperature gauge or indicator…
because if you see the flow decreasing it’s a sure sign that something is going on
down deeper in the motor, but just to be sure you want to check it for obstructions to make sure you
don’t have a clog right at the output. On the other end is the water intake…
and it’s a common place to find a lot of overheating problems. The water flows in, but
so does any trash, leaves, or anything else it can pick up as the boat moves through the water. Now
there’s a little cover that prevents trash from moving up into the cooling system, put it can get
clogged up and that can keep water from getting up into the cooling system where it needs to go.
Now… if you’ve checked the intake and the output and they’re both clear and you’re still not seeing
water coming out of that tell-tale… then you’re gonna have to dig a little deeper. The third place
you’re gonna want to check is the water pump… and it sits at the top of the lower unit of your
outboard and pushed water up to the powerhead… and that may be your problem. To inspect it…
you’ll need to remove the lower unit on your outboard… and we’ve got
several videos addressing that process and getting you to the water pump.
Inside it… there’s going to be a rubber impeller that is driven by the drive shaft… and over time
that rubber gets brittle and wears out and can break. Now if that happens… it can create
a couple of problems. First… broken impeller fins aren’t pushing water into the powerhead…
but second… pieces of those broken impeller fins and get loose and cause obstructions deeper in the
cooling system. Now if you need to replace yours… we have several videos on how to do it and you can
buy just the impeller itself or a whole water pump repair kit for several manufacturers at Boats.net.
If your water pump is in good shape and you don’t have any obstructions on either
end of the cooling system, this fourth area we’re gonna check out could be your problem.
Your thermostat controls how much water moves through the powerhead… and if it fails in the
closed position… it’s going to shut off water flow through the motor. Now they can fail in the open
position… but that’s a little bit of a different problem where so much water flows through that the
motor can’t warm up… which is a completely different story for another video. Now you can’t
repair a thermostat… if it goes bad you just have to replace it. Some outboards have more than one…
and if that’s the case on your motor you should probably go ahead and replace all of them
since parts like that tend to wear out together. Now if all else fails… you’re left with the fifth
thing you might have going wrong on your cooling system… and that’s clogged water
channels running up to and around the powerhead. Now the way to prevent a lot of that is to flush
your outboard after every use… especially if you run in salt water. On a newer outboard? Well, it
takes a long time to get that kind of buildup… but an older unit that hasn’t been maintained properly
can have enough salt and marine gunk up in there that it’ll slow down… or stop… the water flow.
And that’s a harder problem to fix once you get those passages clogged up inside the motor.
Alright guys, there you have it. Just a few places to check
out if you’re experiencing overheating issues.
And just remember… if you flush the outboard after every use and follow your manufacturer’s
guidelines about replacing that water pump impeller… you can dodge a lot of issues.
Well listen, if you need cooling system parts or any other parts for your boat,
why don't you come see us at boats.net and we can get you taken care of.
If you have any questions or comments, leave them in the section below
and I’ll do my best to answer them. We just want to say thank you for
shopping here with us at boats.net and we will see you in the next video.