Outboard cooling water

hey there dangos jr. today's video is about the past that the cooling water takes through an outboard power head and is probably sponsored by marine engine I [Music] think most people are pretty familiar with the path the cooling water takes from the leg down those side grills up into the water pump through the impeller then up the water pipe to the power head but I think it gets a little bit more mysterious after that so that's what we're going to be focusing on today what I've got here is the power head from a Yamaha two-stroke 2 cylinder probably about a 15 horsepower or something like that quite remember where it's from and we're just going to sort of take the part and have a look at the actual path the water follows so once the cooling water comes up from the pump it enters this particular outboard block down here so Salus the water comes up to this little opening here and when it comes in under this exhaust cover so we'll be taking that off as well I also just remembered where this outboard came from it was a Yamaha 20 that had thrown a bearing and put the rods through the side of the block this is the exhaust cover here and this little barb here is where the hose for the telltale comes from so we've got this cover nothing particularly special about it and the outlet here this outlet for the tell-tale isn't actually from this cavity here this telltale outlet from this side comes through actually to this flange surface and picks up from below here as well so we'll actually work a little back we'll go inside here and then I'll show you the part that takes before it comes back out that hole these have always got gaskets and things on the monster they're missing in this case because it's been pulled apart but we've got this kind then underneath here we've got the exhaust ports from the outboard so these shapes here are just designed to deflect the gases to give it a sort of a smooth curve to flow so you don't get that turbulence quite a bit goes into design in this side of a two-stroke motor because in order to get those exhaust gasses out it needs quite a specific shape to the exhaust whereas with a four-stroke it's simply that Pistons sort of pushing exhaust gasses out before we move on though I will show you one other thing to do with this exhaust which is there's two little openings here and here and with this on you can see that inside this other cover that opening here goes through this little gallery when this covers on this port here is connected to this port here through this little sort of convoluted gallery and this port here we take this head off inside the cylinders here you've got your intake and your exhaust port your exhaust ports the one on this side here heading over to here this one's actually missing a huge chunk you can see the cylinder walls broken but then you can see this little port there we go a little round on there in front of a torch so if we come back to these two ports the main exhaust port and this little hole here you'll see this little hole if I shine the torch through it comes out through that little hole so this little gallery here is a path that connects this little exhaust port with the main exhaust port there and I'm sure somebody who's really into two strokes will be able to comment and tell us exactly why that is because I've got no idea anyway I'll stop telling you I don't know and tell you I do know which is about the cooling water so when the water comes through here one of the first place that can go is come out through this hole here so I'll show you where that then leads so you can hopefully see that that's directly connected light shines straight through there they can come up into the top here once cooling waters come through here up here and onto the top here you can go down all these little holes we just saw so one of them is this one here if I come round this way and show you and then we shine torch down there hopefully you can see that this one lights up so that's actually connected like nothing more complicated than being a single space here so once waters gone down here the pressure forces it out here and that's the outlet for the tell-tale so if you're telltale is running what it's telling you is that water's coming up from the block it's coming through here it's coming down here back out here and out the tell-tale that's not enough to call the motor so that's why having your telltale working till she your pumps pumping water but it doesn't tell you that your motors actually being cooled by that water so I think that's really the first take-home message from this is that a telltale is simply an indication that your water pumps working it's not indication that your motor is actually being cooled so you can have a really good telltale and still have a motor overheating the real job of cooling the outboard comes when the water goes down these other holes here because they lead to the water jackets around the Pistons so I'll show you your sort of shine the light and show you how that works we've got a hole on top here the cooling water gets to and these were water jackets around the Pistons so if I shine the torch in that hole up there you can see light shining here down goes the other one shining down inside the water jackets if I then take this little inspection camera and put it inside the water jackets of this bottom cylinder so you can see here that's the cylinder then there's the cylinder wall and the water jacket here then if we go inside this water jacket upper top because this little passage we can go into there and we'll see and see that light shining you take a light away and that light is to here so we know that's directly connected to right so where does that get us what it means is if we have all our cover plates on like this we've got a good working pump what is going to coming in here is going to be coming on to the top here it's going to be going directly into this bottom jacket it's going to be going down these Epogen to the jackets as well it's going to be coming down here and out the tell-tale so we'll have water sitting around the water jacket so there will be water there and we'll have a flying telltale what we'll do now is move around to the actual cylinder head and we'll see what happens next all our waters come in here from this side it's free to flow and fill all these water jackets around the Pistons here and then it kind of stops and what happens if I pop the cylinder head on so once the water comes up through the bottom here it can come up into here it can flow through all these spaces it can flow around here can flow right up the sides when all this water eventually gets to the end of the road this is where it stops there's a little aperture here that also just goes down in the water jackets so water can flow up through there as well and then it comes up and goes into here what's in here is your thermostat so thermostat cover gasket goes around that and then inside here is a pretty main key looking thermostat but the point being the hot water comes up to this side of thermostat this is the side with a little wax plug that expands with temperature so this here is a thermostat in its closed position and if we heated that up this would open and allow the water to flow but in this case it's currently blocked off I'll go boil some water and I'll throw this in and show you what happens interesting to see if it still works it's pretty monkey but it may still work just a glass of hot water boiling water will pop the thermostat in and we'll see what it does I think we can pretty much call this thermostat dead as you can see there it hasn't opened at all what it will do though is just open a new one and show you what they're supposed to do so that's what they look like closed and that's what they look like open and eventually as this cools down that little plunger will recede back in so it's a pretty simple test you can do to make sure your thermostats working what it means for the flow of the water if your thermostat is stuck clothes like this is that water will come up it'll come out the tell-tale all these water jackets will fill presuming they're not blocked with anything then the water will get to the top here where the thermostat is and it'll stop it'll keep flowing at the tell-tale because it needs to come out somewhere and you'll have this sort of pressurized water sitting inside the jackets and that water will just get hotter and hotter and hotter eventually it'll turn to steam and you might have a bit of steam coming out the telltale but the engine will gradually overheat even though it is actually surrounded by water the purpose of the thermostat is to get a motor up to temperature quickly so it lets that water sit there until it's hot enough and then when it gets to the right temperature it opens allows the water to flow if the engine actually starts to get too cool it'll just close again it just regulates the temperature so it gets it to a temperature quick and then it keeps it at that correct temperature the whole time thermostats will often have the temperature printed on the temperature they're designed to open it so if we look at this one hopefully you can see they're 50 degrees Celsius is when this one opens I'll bring you in close again and just sort of show you the final piece of the puzzle now so cooling water was coming up here to the thermostat the thermostat opens this little cover just provides a part of the water to loop back over so the work comes out the thermostat and then back down here that passage simply comes into here it runs down the other side when the water gets to the bottom here it goes down this hole and therefore shine light through here we can see that light coming out to places inside the casing and then down here that goes inside this exhaust manifold and this is where the exhaust comes out here this is the exhaust for this outboard and if we imagine this bolted on here this outlet here comes into here which actually just goes straight to here and then it flows down the outside so it looks like it's designed to run down the outside of the exhaust to keep it cool it doesn't actually go through the center so I hope this video helps you understand the path but what it takes and I hope that knowledge of the path to what it takes will help you diagnose overheating problems if you're having them a good tool towel just means your pumps working and a working pump means nothing unless you've got a working thermostat taking the thermostat out means the motor is going to be running cool all the time it's better than the motor overheating you know this failure may have actually been due to that thermistor being stuck so if the thermostat wasn't there child status motors still be working but if you take the thermostat out it's going to be running cool your efficiency is not going to be good your fuel efficiency you might find your plugs foul up your emissions won't be as good it's not ideal to have no thermostat in a boat I wish I'd filmed it but I actually had a boats in the shop at the moment that was overheating it had a good telltale and the thermostat was working and if I took the thermostat out ran the motor lots of water was coming out the thermostat hole so in that situation I'm normally pretty confident that cooling is working properly if you can take the thermostat cover off and water's coming out the thermostat and you know it's good themselves actually brand new something else is going on so I took the hit off that motor and this is what I found there was a big chunk here missing from the cylinder wall now oddly this actually had perfectly even compression on both cylinders so go to show compression tests are a little bit hidden miss but it was obviously a problem here now another big clue to it was the nature of the tell-tale the tilt I was actually quite forceful and was a little bit sporadic in its kind of pulses and what that is is exhaust gases coming past this cylinder water'll blown head gasket and displacing all that water the water was being pumped in by the pump but then the exhaust gasses were much stronger and they were just pushing exhaust gasses into the water jackets flashing net water out with such force was actually flowing all the way backwards and pushing these gases out the tell-tale so that's a really good sign of a blown head gasket so although the cooling system on this motor was working perfectly good pump good thermostat no blockages it was actually the blown head gasket that was causing this motor to overheat well I hope you enjoyed this video I sort of hope it solved the mystery of where all this calling what it goes if you weren't familiar with it and I hope that information does help you if you're having a problem with your outboard because although you don't always need to understand it it certainly can help with your thinking when you're trying to figure out what's going on with your outboard alright we'll take care of and I'll see you next week [Music]

Channel: Dangar Marine

Views: 119,026

Rating: 4.9289398 out of 5

Keywords: outboard motor, outboard, cooling water, cooling, water, path, thermostat

Id: joEQChcZl2A

Length: 14min 1sec (841 seconds)

Published: Sat Aug 12 2017