I have twin 150’s I recently noticed the port motor has steam coming from upper exhaust port. I changed Tstats and Impeller with no change. Oil level is same and is not milky. What can it be ? Thanks!!
2006 Yamaha 150txr steaming from exhaust port
- Thread starter Jzeno186
- Start date
Do you have a pic or video? Is it at start up, idle, running on plane, all the time? Is there oil in the water?
I don’t have a video of my engine. I checked the oil which looks good, not watery level hasn’t risen. It does it at idle throughout the day. I found a video online of an engine doing the same thing but cannot post a video on here ?
Does the motor spit 'steam' all the time or when cold, or hot?
The first step is to determine if the motor is indeed running hot or not. If you don't have a display of engine temperature, the easiest way to check is to use an IR contactless thermometer. It's a handy dandy tool and serves a lot of purposes. Inexpensive ones can be had for less than $50 at the big box stores and Harbor Freight.
To use it you remove the cowling and check for hot spots. Just pointing the thermometer at the thermostat housing will help determine if there is a cooling issue. It will help to measure the normal temps on the good motor for comparison.
Some steam is common in certain weather conditions such as cold weather, Although I said that I doubted it could be a stuck poppet valve, on further thinking it could be but if so the engine would be running hotter than normal so the IR thermo test should be done.
The first step is to determine if the motor is indeed running hot or not. If you don't have a display of engine temperature, the easiest way to check is to use an IR contactless thermometer. It's a handy dandy tool and serves a lot of purposes. Inexpensive ones can be had for less than $50 at the big box stores and Harbor Freight.
To use it you remove the cowling and check for hot spots. Just pointing the thermometer at the thermostat housing will help determine if there is a cooling issue. It will help to measure the normal temps on the good motor for comparison.
Some steam is common in certain weather conditions such as cold weather, Although I said that I doubted it could be a stuck poppet valve, on further thinking it could be but if so the engine would be running hotter than normal so the IR thermo test should be done.
So I have temp gauges on both engines. At idle the are dead center, up on plane they go 1 dot past center and usually both at the same time, once I back off they both return to center. Each motor is consistent with rpm a temps. It appears to only do it at idle.when it’s cooler out both engines do it however this one is significantly more. When it’s warm out the starboard motor puts no steam out while at idle while the port motor now does.
Although not Yamahas, I have a boat with Mercs and they also spew what looks like steam. One does it more than the other. Since I couldn't find anything wrong with temps and water pressure, I learned to not get concerned
My old 2 stroke SX motor would also spew a cloud of mist when the ambient temp was low ( 60s or there about)
My old 2 stroke SX motor would also spew a cloud of mist when the ambient temp was low ( 60s or there about)
Mustang65fbk
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As mentioned in the other almost identical thread to this one, steam is a common thing, especially at low speeds and when it’s a cool/colder morning.
Sardinia306Canyon
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Does one of both engines bubble more from the prop when in idle?
Could be that one engine has a clogged low rpm exhaust (where the seam exits) and the other not.
At least on the 4.2L you have to pull the side panel to unscrew the black plastic box and verify if there is something clogged.
Chris
Could be that one engine has a clogged low rpm exhaust (where the seam exits) and the other not.
At least on the 4.2L you have to pull the side panel to unscrew the black plastic box and verify if there is something clogged.
Chris
Mustang65fbk
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I really don't believe it's too much to be concerned about. You could always call up your local GW/Yamaha dealer and see what they have to say on the matter.