Mercury outboard blowing steam

[OFF SIDE]

Hey all. I have a 1987 50hp Mercury 2 stroke outboard, tell tale is blowing steam.
When in the lake put a temperature gun on the engine and recorded 90c and climbing.
There's no thermostat on this engine. Removed lower end checked the new impeller everything looks good. Put air to the intake water pipe, air coming out of tell tale. Mechanic mentioned some Mercury's blow steam, I've never heard or seen this happen on a boat motor.

 

[airshot]

Me either !!

 

[The Force power]

Hey all. I have a 1987 50hp Mercury 2 stroke outboard, tell tale is blowing steam.
When in the lake put a temperature gun on the engine and recorded 90c and climbing.
There's no thermostat on this engine. Removed lower end checked the new impeller everything looks good. Put air to the intake water pipe, air coming out of tell tale. Mechanic mentioned some Mercury's blow steam, I've never heard or seen this happen on a boat motor.

Tiny bugs like to plug-up the tell-tail & beyond causing very little water to pass through.
Remove the the hose & feed picture wire through and try to rotate go as far as you possibly can.
Are you sure the water tube is secured into the powerhead and not leaking?

 

[crazy charlie]

In damp or humid weather the exhaust may seem like steam but is just warm exhaust.Steam is something that is going to be very hot to the touch and simply means that water circulation is compromised.Put your hand by the exhaust ports and if it is hot enough to burn your hand then you are correct that it is steam and you have an issue.If it is warm to the touch then it is probably normal.Charlie

 

[crazy charlie]

Just read your thread again.If steam is coming from where water should be flowing, then your impeller is either bad or installed backwards.No water flow.Charlie

 

[demarko210]

I have 2003 efi 150 and mines blow steam when the water temps gets about 60 degrees or less and only in the fall winter and sprint time. Its a 2 stroke does not smoke in the summer (at least you cant see it but smell) months but in the winter you can see smoke from the back exhaust and tell as the cold water runs through the warm engine.

Not sure what your water temps are!

 

[OFF SIDE]

Tks all. With the muffs on the water is still steaming out of the tell tale. At the prop location
where the water ejects water is alot cooler.
Is the supposed to be water coming out of the exhaust port at top of shaft?

 

[racerone]

Check the NLA fitting and grommet found at the top of the water tube.----If bad you have to find a used one or make one.-----Check water jackets for debris / old impeller bits.------And if there was severe overheat post your compression numbers.

 

[The Force power]

Check the NLA fitting and grommet found at the top of the water tube.----If bad you have to find a used one or make one.-----Check water jackets for debris / old impeller bits.------And if there was severe overheat post your compression numbers.

YUP

 

[OFF SIDE]

In damp or humid weather the exhaust may seem like steam but is just warm exhaust.Steam is something that is going to be very hot to the touch and simply means that water circulation is compromised.Put your hand by the exhaust ports and if it is hot enough to burn your hand then you are correct that it is steam and you have an issue.If it is warm to the touch then it is probably normal.Charlie

Tks. The two exhaust ports on the shaft have no water coming out. There is water coming out from the prop thou. The tel tale is shooting out water, just turns to steam after running for awhile

 

[The Force power]

The two exhaust ports on the shaft have no water coming out. There is water coming out from the prop thou.

Yup, not when you're running on muffs

The tel tale is shooting out water, just turns to steam after running for awhile

As racerone mentioned; the lines could be jammed with debris
and may slip shut by being cramped together by the water pushing it.
Reverse the water flow or pull the water jacket