where does water exit from Yamaha 4HP outboard

tudorsailor

tudorsailor

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I have a Yamaha 4HP outboard. It has been serviced having been immersed (not by me). It works ok but when I was flushing with fresh water today I wondered where the cooling water exited. I think I am going senile, as I thought it squirted out the back over the water level, I had the engine on the rail with the base in a bucket up to the anti cavitation plate. I runs fine but I have confused myself by thinking that there used to be water squirting out. There is a lot of bubbling in the bucket so does the water exit under the water level?

Anyone out there with the same engine??

Thanks

TS
 
tudorsailor said:
I have a Yamaha 4HP outboard. It has been serviced having been immersed (not by me). It works ok but when I was flushing with fresh water today I wondered where the cooling water exited. I think I am going senile, as I thought it squirted out the back over the water level, I had the engine on the rail with the base in a bucket up to the anti cavitation plate. I runs fine but I have confused myself by thinking that there used to be water squirting out. There is a lot of bubbling in the bucket so does the water exit under the water level?

Anyone out there with the same engine??

Thanks

TS
Click to expand...

Most of the cooling water will exit under water with the exhaust. Some will be blown out as droplets or a mist from the back pressure relief ports on the leg.

IF there is a tell tale (aka peehole) then water should exit from this in a steady stream .

The handbook should tell you about the telltale if there is one. If there is and no water is coming out it may simply be blocked. Locate it and poke a wire through it. If its connected to the block with a hose make sure the hose and the connection to the block are clear.

You do not give any engine details. 2stroke, 4 stroke year year model/serial numbers so have not been able to look up any info.
You may find a manual on the Yamaha site if it is fairly recent model if you have mislaid your copy.
 
tudorsailor said:
I have a Yamaha 4HP outboard. It has been serviced having been immersed (not by me). It works ok but when I was flushing with fresh water today I wondered where the cooling water exited. I think I am going senile, as I thought it squirted out the back over the water level, I had the engine on the rail with the base in a bucket up to the anti cavitation plate. I runs fine but I have confused myself by thinking that there used to be water squirting out. There is a lot of bubbling in the bucket so does the water exit under the water level?

Anyone out there with the same engine??

Thanks

TS
Click to expand...

Mine is one of these, it shows the cooling water exit..

http://youtu.be/EPmMWM87mQA
 
Beware !

Yes there should be a telltale stream of water from the aft face of the leg, just under the motor head.

Especially after a dunking, but as a regular check anyway, I'd be concerned that the waterways are salted up.

I take the heads off my engines ( Yam 4 now Mariner 5, Mariner 2 ) every winter, even with flushing in fresh water at beginning and end of season this has proved necessary.

When water does exit it should be cold; I'd be thinking about whipping the head off.
 
Seajet said:
Beware !

Yes there should be a telltale stream of water from the aft face of the leg, just under the motor head.

Especially after a dunking, but as a regular check anyway, I'd be concerned that the waterways are salted up.

I take the heads off my engines ( Yam 4 now Mariner 5, Mariner 2 ) every winter, even with flushing in fresh water at beginning and end of season this has proved necessary.

When water does exit it should be cold; I'd be thinking about whipping the head off.
Click to expand...

Never flushed my much abused 4hp Yamaha in its life, i have had it from new which was about 8 years ago and it gets lots and lots of salt water use of but has never complained about not being flushed.

Telltale is like stated on the back on the opposite side as the tiller arm.
 
tyce said:
Never flushed my much abused 4hp Yamaha in its life, i have had it from new which was about 8 years ago and it gets lots and lots of salt water use of but has never complained about not being flushed.

Telltale is like stated on the back on the opposite side as the tiller arm.
Click to expand...

Yeah... mine gets flushed twice a year... end of season, and during service... :rolleyes:
 
To be logical, flushing will only be of much value if done at the end of each saltwater run.

If you leave the motor, warm, with saltwater in the cooling channels, that is when the deposits will form. A flush now and then will only remove the most recent and softer build-up.
 
For this reason our club has a tank of fresh water at the top of the slip, but this will of course only help tender engines, not yachts'; hence taking the head off at end of season.
 
Yamaha

VicS said:
Most of the cooling water will exit under water with the exhaust. Some will be blown out as droplets or a mist from the back pressure relief ports on the leg.

IF there is a tell tale (aka peehole) then water should exit from this in a steady stream .

The handbook should tell you about the telltale if there is one. If there is and no water is coming out it may simply be blocked. Locate it and poke a wire through it. If its connected to the block with a hose make sure the hose and the connection to the block are clear.

You do not give any engine details. 2stroke, 4 stroke year year model/serial numbers so have not been able to look up any info.
You may find a manual on the Yamaha site if it is fairly recent model if you have mislaid your copy.
Click to expand...

Foolish me! The outboard is 2005 4 stroke. Model type F4A Serial number M1404299909

Thanks

TudorSailor
 
Then it's one of these and should have a strong and steady pee stream. see at 49 seconds. (mine did, this is not mine)

​
 
Last edited:
You said you were running it in a bucket, and there was lots of frothing. I've run an outboard in a bucket too - and also ended up turning it off pretty quickly when I realised no water was coming out of the tell-tale. I think a bucket's just too small - the water splashes about and doesn't get sucked up properly. I'd try it in something larger - a dustbin seems to be the recommended option - before you start dismantling it in a big way!

Cheers
Patrick
 
YachtAllegro said:
You said you were running it in a bucket, and there was lots of frothing. I've run an outboard in a bucket too - and also ended up turning it off pretty quickly when I realised no water was coming out of the tell-tale. I think a bucket's just too small - the water splashes about and doesn't get sucked up properly. I'd try it in something larger - a dustbin seems to be the recommended option - before you start dismantling it in a big way!

Cheers
Patrick
Click to expand...
One important thing to be aware of! The water pump operates as soon as the engine turns over as they are connected by the drive shaft BUT the tell tale outlet is connected to the thermostat housing. It is only physically possible for the tell tale water to flow once the thermostat opens about 2 minutes after start up. Before you start dropping the lower unit if you have any doubts, it’s far easier to open the thermostat housing (3 bolts, 10mm wrench, 2 minutes) and remove the thermostat then put the housing back on. If the pump works and the tell tale is not blocked you will get water from the tell tale after 5 seconds. Thermostat operation can be checked by putting in a saucepan of hot tap water and then raising the temperature slowly on the stove and you should see it slowly open as the temperature rises. Don’t overheat it. Once it’s opened fish it out with a spoon and as it cools it should quickly close. Assuming it works fine put it back in the housing. You don’t have a problem!
 
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