Outboard motor overheating!

[Setrakco]

I have literally tried everything just to fix my motor from overheating. I have changed the impeller which was worn out. Changed the thermostat and even cleaned the water passage by using a sink unblocker. And still the flowrate at the outlet of the motor is very slow and also very hot.
Please if you could possibly give me any suggestions to fix this problem.

 

[ST840]

Have you tried “rodding” the tell tell water outlet? I know you said you’ve cleaned it , but maybe still a slight blockage.

 

[lynallbel]

Pop the head off, you might be scared by what you find!

 

[Setrakco]

Have you tried “rodding” the tell tell water outlet? I know you said you’ve cleaned it , but maybe still a slight blockage.

Im happy to try it. Could you provide me with a guidline, the tools that i can use for this process.

 

[Setrakco]

Pop the head off, you might be scared by what you find!

It’s clean. Unfortunately, even the mechanic couldn’t figure out the problem. Going to change the gasket in a couple of days. I hope this would fix the issue.

 

[Kawasaki]

I have literally tried everything just to fix my motor from overheating. I have changed the impeller which was worn out. Changed the thermostat and even cleaned the water passage by using a sink unblocker. And still the flowrate at the outlet of the motor is very slow and also very hot.
Please if you could possibly give me any suggestions to fix this problem.

Gis a Clue
What make/model/HP / year etc?

 

[Setrakco]

Gis a Clue
What make/model/HP / year etc?

Yamaha E40XMHL model, 40HP, Not sure about the production year probably 2010. Any help would be appreciated.

 

[BruceK]

There was a couple outboards that had a mismatched powerhead to gearbox alloy that caused corrosion and blockage of the raw water port at the mating face when it squeezed the grommet shut . Some mariner's were prone to this especially. Do a google search on "outboard grommet overheating problems"

 

[Setrakco]

There was a couple outboards that had a mismatched powerhead to gearbox alloy that caused corrosion and blockage of the raw water port at the mating face when it squeezed the grommet shut . Some mariner's were prone to this especially. Do a google search on "outboard grommet overheating problems"

Noted.
Will definitely take that into consideration.
Any other possibilities which this might occur?

 

[[2068]]

Have you tried “rodding” the tell tell water outlet? I know you said you’ve cleaned it , but maybe still a slight blockage.

This makes no sense.
The tell tale is just that - a visual indication of whether water is circulating.
Most of the cooling water exits with the exhaust.

The tell tale can be blocked completely and the outboard can still work perfectly.

 

[burgundyben]

The tell tale can be blocked completely and the outboard can still work perfectly.

Quite right. Mine is like that at the moment.

 

[Oscar24]

Quite right. Mine is like that at the moment.

So is mine,
I flush my OB with fresh water after every trip out but its not uncommon for the Tell tale to block up at tick over. Usually clears at high revs or sometimes if i stop and re-start it. I always keep an eye on the temp gauge just incase.

 

[northwind]

I have literally tried everything just to fix my motor from overheating. I have changed the impeller which was worn out. Changed the thermostat and even cleaned the water passage by using a sink unblocker. And still the flowrate at the outlet of the motor is very slow and also very hot.
Please if you could possibly give me any suggestions to fix this problem.

Is the impeller in the water pump OK? Does it have the key pin installed, i. e. Is it being driven by the prop shaft? Is the inlet blocked? Is the pipe up the leg attached correctly to the gearbox?

If you attach a hose to it, does it pee any better?

As other have said, take the powerhead off the leg and check and clean the waterways ideally, scraping them clean, not relying on gunk to clean it out, also force air through the pickup tube to check its clear

 

[spannerman]

A simple check if you know the impellor is ok is to take off the thermostat cover and thermostat and run the engine and see if the block fills up with water and has a decent flow out of the thermostat hole. If its slow then its a safe bet the problem is corrosion around the grommet where the water pipe comes up from the pump to the powerhead.

 

[Setrakco]

Is the impeller in the water pump OK? Does it have the key pin installed, i. e. Is it being driven by the prop shaft? Is the inlet blocked? Is the pipe up the leg attached correctly to the gearbox?

If you attach a hose to it, does it pee any better?

As other have said, take the powerhead off the leg and check and clean the waterways ideally, scraping them clean, not relying on gunk to clean it out, also force air through the pickup tube to check its clear

Is the impeller in the water pump OK? Does it have the key pin installed, i. e. Is it being driven by the prop shaft? Is the inlet blocked? Is the pipe up the leg attached correctly to the gearbox?

If you attach a hose to it, does it pee any better?

As other have said, take the powerhead off the leg and check and clean the waterways ideally, scraping them clean, not relying on gunk to clean it out, also force air through the pickup tube to check its clear

Will definitely check the listed above. Thank you a lot.

 

[Setrakco]

A simple check if you know the impellor is ok is to take off the thermostat cover and thermostat and run the engine and see if the block fills up with water and has a decent flow out of the thermostat hole. If its slow then its a safe bet the problem is corrosion around the grommet where the water pipe comes up from the pump to the powerhead.

Why didn’t I thought of that. Will check taht as soon as possible and let u know.

 

[Setrakco]

Thank you all for your help.
The issue was discovered and solved. The inlet pipe was damaged. The water was leaking which resulted a low flowrate to the system.
Once again thank you all for the idea.