I've had my 1984 Yamaha 9.9hp motor for about a year now. Sometimes it pees very well but often there is only a trickle of water out the tell tale vent. I've also had a new impeller installed thinking that was the problem. But the intermittent flow still keeps me worried. I've taken off all the hoses that circulate the water and made sure they are clear. At the foot of the motor, just in front of the propeller, there is a screened opening that, I assume, is where the water is drawn in and expelled. It too is clear. So where could the clogging, if that's what's happening, be taking place? Does any one know if there is an internet site where I could find some drawings/sketches showing how the cooling water circulates? Most folks tell me not to worry. One told me that if the head is not so hot that it can't be touched, it's OK. But that would mean sailing with the cowling off and I don't want to do that. Another told me to take the thermostat of and that would solve the problem. This may be OK but it doesn't seem to be the way to tackle the problem. Any suggestions?
Outboard Motor Cooling System
- Thread starter Tony23670
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I've had my 1984 Yamaha 9.9hp motor for about a year now. Sometimes it pees very well but often there is only a trickle of water out the tell tale vent. I've also had a new impeller installed thinking that was the problem. But the intermittent flow still keeps me worried. I've taken off all the hoses that circulate the water and made sure they are clear. At the foot of the motor, just in front of the propeller, there is a screened opening that, I assume, is where the water is drawn in and expelled. It too is clear. So where could the clogging, if that's what's happening, be taking place? Does any one know if there is an internet site where I could find some drawings/sketches showing how the cooling water circulates? Most folks tell me not to worry. One told me that if the head is not so hot that it can't be touched, it's OK. But that would mean sailing with the cowling off and I don't want to do that. Another told me to take the thermostat of and that would solve the problem. This may be OK but it doesn't seem to be the way to tackle the problem. Any suggestions?
Thermostat
You have answered your own problem, sort of. The thermostat is only going to open when needed to keep engine operating temps up to normal. Will depend to some extent on the temp of the water being taken in. Basically when the thermostat opens you have a good flow, as the thermostat closes flow is reduced. Sounds like it is working as it should. If you take the thermostat out, the water flow will be steady, and this will eliminate your worries about the thing peeing plenty of water, but it will be running very cold and will not perform as it should.
You have answered your own problem, sort of. The thermostat is only going to open when needed to keep engine operating temps up to normal. Will depend to some extent on the temp of the water being taken in. Basically when the thermostat opens you have a good flow, as the thermostat closes flow is reduced. Sounds like it is working as it should. If you take the thermostat out, the water flow will be steady, and this will eliminate your worries about the thing peeing plenty of water, but it will be running very cold and will not perform as it should.
Thermostat
You have answered your own problem, sort of. The thermostat is only going to open when needed to keep engine operating temps up to normal. Will depend to some extent on the temp of the water being taken in. Basically when the thermostat opens you have a good flow, as the thermostat closes flow is reduced. Sounds like it is working as it should. If you take the thermostat out, the water flow will be steady, and this will eliminate your worries about the thing peeing plenty of water, but it will be running very cold and will not perform as it should.
You have answered your own problem, sort of. The thermostat is only going to open when needed to keep engine operating temps up to normal. Will depend to some extent on the temp of the water being taken in. Basically when the thermostat opens you have a good flow, as the thermostat closes flow is reduced. Sounds like it is working as it should. If you take the thermostat out, the water flow will be steady, and this will eliminate your worries about the thing peeing plenty of water, but it will be running very cold and will not perform as it should.
Yamaha outboard
Just something easy to check out if you have not already. I had a 1985 Yamaha 8 hp growing up. The engine water indicator would trickle water but it ran fine. My problem was that the indicator clogged. I had a tooth pick I would push up the indicator to on clog it. I now have a 1997 yamaha 6 hp that does the same thing.
Just something easy to check out if you have not already. I had a 1985 Yamaha 8 hp growing up. The engine water indicator would trickle water but it ran fine. My problem was that the indicator clogged. I had a tooth pick I would push up the indicator to on clog it. I now have a 1997 yamaha 6 hp that does the same thing.
Yamaha outboard
Just something easy to check out if you have not already. I had a 1985 Yamaha 8 hp growing up. The engine water indicator would trickle water but it ran fine. My problem was that the indicator clogged. I had a tooth pick I would push up the indicator to on clog it. I now have a 1997 yamaha 6 hp that does the same thing.
Just something easy to check out if you have not already. I had a 1985 Yamaha 8 hp growing up. The engine water indicator would trickle water but it ran fine. My problem was that the indicator clogged. I had a tooth pick I would push up the indicator to on clog it. I now have a 1997 yamaha 6 hp that does the same thing.
Toothpick or ...
.. a piece of aluminum wire. My 9.9 Nissan 2-stroke's tell-tale would likewise stop, so I put a piece of wire in and reamed it about. (I have no thermostat. Does the Yamaha have one?)
.. a piece of aluminum wire. My 9.9 Nissan 2-stroke's tell-tale would likewise stop, so I put a piece of wire in and reamed it about. (I have no thermostat. Does the Yamaha have one?)
Toothpick or ...
.. a piece of aluminum wire. My 9.9 Nissan 2-stroke's tell-tale would likewise stop, so I put a piece of wire in and reamed it about. (I have no thermostat. Does the Yamaha have one?)
.. a piece of aluminum wire. My 9.9 Nissan 2-stroke's tell-tale would likewise stop, so I put a piece of wire in and reamed it about. (I have no thermostat. Does the Yamaha have one?)
This is one of the biggest problems of outboards...
removing the thermostat could help as this is one place sediment and silt get trapped in outboards. Also in Florida, you really don't need the thermostat. This is especially true on an old outboard that doesn't have an electronic control system. Are you flushing the outboard with freshwater after each use? You should be. Sometimes the tell-tale fitting also gets clogged.
removing the thermostat could help as this is one place sediment and silt get trapped in outboards. Also in Florida, you really don't need the thermostat. This is especially true on an old outboard that doesn't have an electronic control system. Are you flushing the outboard with freshwater after each use? You should be. Sometimes the tell-tale fitting also gets clogged.
This is one of the biggest problems of outboards...
removing the thermostat could help as this is one place sediment and silt get trapped in outboards. Also in Florida, you really don't need the thermostat. This is especially true on an old outboard that doesn't have an electronic control system. Are you flushing the outboard with freshwater after each use? You should be. Sometimes the tell-tale fitting also gets clogged.
removing the thermostat could help as this is one place sediment and silt get trapped in outboards. Also in Florida, you really don't need the thermostat. This is especially true on an old outboard that doesn't have an electronic control system. Are you flushing the outboard with freshwater after each use? You should be. Sometimes the tell-tale fitting also gets clogged.
My Yamaha 9.9 did the same thing
I have the manual at home and can copy any page you need. However, there really is a very good descriptive on the cooling system. The solution for me was to fill a large trash bag with a gallon of vinegar and I think two gallons of water. I then put the drive unit in the solution and started the engine. The intake sucked in the solution and when it started to trickle out, I shut her down. Came back a week later and drained the system. Fired up the outboard and she trickled for a few seconds then spat out a bunch of crap, with a little help from a toothpick. The stream is very steady now. The vinegar broke down the calcium and salt in the pipes. There is a thread about this in the archive started by me with some pictures. Do a search for it. You will find the answer for the vinegar/water solution. Good luck.
I have the manual at home and can copy any page you need. However, there really is a very good descriptive on the cooling system. The solution for me was to fill a large trash bag with a gallon of vinegar and I think two gallons of water. I then put the drive unit in the solution and started the engine. The intake sucked in the solution and when it started to trickle out, I shut her down. Came back a week later and drained the system. Fired up the outboard and she trickled for a few seconds then spat out a bunch of crap, with a little help from a toothpick. The stream is very steady now. The vinegar broke down the calcium and salt in the pipes. There is a thread about this in the archive started by me with some pictures. Do a search for it. You will find the answer for the vinegar/water solution. Good luck.
My Yamaha 9.9 did the same thing
I have the manual at home and can copy any page you need. However, there really is a very good descriptive on the cooling system. The solution for me was to fill a large trash bag with a gallon of vinegar and I think two gallons of water. I then put the drive unit in the solution and started the engine. The intake sucked in the solution and when it started to trickle out, I shut her down. Came back a week later and drained the system. Fired up the outboard and she trickled for a few seconds then spat out a bunch of crap, with a little help from a toothpick. The stream is very steady now. The vinegar broke down the calcium and salt in the pipes. There is a thread about this in the archive started by me with some pictures. Do a search for it. You will find the answer for the vinegar/water solution. Good luck.
I have the manual at home and can copy any page you need. However, there really is a very good descriptive on the cooling system. The solution for me was to fill a large trash bag with a gallon of vinegar and I think two gallons of water. I then put the drive unit in the solution and started the engine. The intake sucked in the solution and when it started to trickle out, I shut her down. Came back a week later and drained the system. Fired up the outboard and she trickled for a few seconds then spat out a bunch of crap, with a little help from a toothpick. The stream is very steady now. The vinegar broke down the calcium and salt in the pipes. There is a thread about this in the archive started by me with some pictures. Do a search for it. You will find the answer for the vinegar/water solution. Good luck.
outboard urology
I use a turkey baster and backflush the pee fitting. Just suck up some seawater and give it a shot. I keep it in the cockpit locker and will stop in transit if I see the stream peter out. Tried using little wires but couldn't fish them in far enough.
I use a turkey baster and backflush the pee fitting. Just suck up some seawater and give it a shot. I keep it in the cockpit locker and will stop in transit if I see the stream peter out. Tried using little wires but couldn't fish them in far enough.
outboard urology
I use a turkey baster and backflush the pee fitting. Just suck up some seawater and give it a shot. I keep it in the cockpit locker and will stop in transit if I see the stream peter out. Tried using little wires but couldn't fish them in far enough.
I use a turkey baster and backflush the pee fitting. Just suck up some seawater and give it a shot. I keep it in the cockpit locker and will stop in transit if I see the stream peter out. Tried using little wires but couldn't fish them in far enough.
can of air
like you would use to clean a computer key board or the computer itself (available at Staples etc) can be use to clean out the water tell tale if clogged as suggested flush with fresh water when ever possible. If tell tale is not clogged you may need to take off the fitting at the engine maybe something has gotten in there
like you would use to clean a computer key board or the computer itself (available at Staples etc) can be use to clean out the water tell tale if clogged as suggested flush with fresh water when ever possible. If tell tale is not clogged you may need to take off the fitting at the engine maybe something has gotten in there
can of air
like you would use to clean a computer key board or the computer itself (available at Staples etc) can be use to clean out the water tell tale if clogged as suggested flush with fresh water when ever possible. If tell tale is not clogged you may need to take off the fitting at the engine maybe something has gotten in there
like you would use to clean a computer key board or the computer itself (available at Staples etc) can be use to clean out the water tell tale if clogged as suggested flush with fresh water when ever possible. If tell tale is not clogged you may need to take off the fitting at the engine maybe something has gotten in there
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