Johnson outboard blowing steam!?!

[dhaglund]

Well, it hasn't been run dry. Not even for a second. It was even lubed at installation.

Tomorrow I will take it apart and see the condition of the newest impeller.

[Oldman2]

What was it lubed with is going to be the next question?

[dhaglund]

Originally Posted by Oldman2

What was it lubed with is going to be the next question?

A little O-ring grease.

[Peter_C]

That impeller looks melted. Something like a bag in the water could cause a lack of water to the impeller, but one would think they would spot a bag. Reverse will often clear kelp and other debris easy enough though, so if reversed was used the bag could have cleared itself.

[A1an]

I reckon I’ve done hundreds of impellers and I’ve never seen one in that state.

[dhaglund]

Thanks for all the feedback. I appreciate it!

Originally Posted by A1an

I reckon I’ve done hundreds of impellers and I’ve never seen one in that state.

I've only done a few impellers, but never seen anything like this. It was most likely turned the wrong way when installed. Also it came from a cheap water pump kit from Amazon. Don't know if that really matters. It looked fine before installing.

Originally Posted by Peter_C

That impeller looks melted. Something like a bag in the water could cause a lack of water to the impeller, but one would think they would spot a bag. Reverse will often clear kelp and other debris easy enough though, so if reversed was used the bag could have cleared itself.

Sorry, there were no debris or bags. Only clean water. But yes, it is melted.

Originally Posted by beamishken

Something wrong with the install or its been run dry to do that damage to a new impeller, they do correct if installed the wrong way , you often find one vane flipped the wrong way because engines rock back as they stop & invert the odd vane. Only time they dont correct is if its an old knackered impeller thats sat for a long time & "set" or gone hard. Even if every vane was wrong way you wouldnt have that damage, you need to look for another cause

Very interesting...

The second impeller I installed looked just fine after 20 minutes in the water. I changed a few things. The vanes were turned the right way this time, I used a little teflon spray lube and the impeller was another brand.

Regardless, cooling is acting strange as can be seen here.
https://photos.app.goo.gl/frzg9KZPR2L6YYDD8

I'm unsure what the next steps should be. Possibly:

1. Reverse flush the cooling system with the lower unit off.
2. Remove the thermostat
3. Check compression again and perform a compression leak-down test to try to find a blown head gasket.
4. Pull the head off to inspect the head gasket and check for debris in the cooling system.

What would you suggest?

[A1an]

Originally Posted by dhaglund

Thanks for all the feedback. I appreciate it!



I've only done a few impellers, but never seen anything like this. It was most likely turned the wrong way when installed. Also it came from a cheap water pump kit from Amazon. Don't know if that really matters. It looked fine before installing.


Sorry, there were no debris or bags. Only clean water. But yes, it is melted.


Very interesting...

The second impeller I installed looked just fine after 20 minutes in the water. I changed a few things. The vanes were turned the right way this time, I used a little teflon spray lube and the impeller was another brand.

Regardless, cooling is acting strange as can be seen here.
https://photos.app.goo.gl/frzg9KZPR2L6YYDD8

I'm unsure what the next steps should be. Possibly:

1. Reverse flush the cooling system with the lower unit off.
2. Remove the thermostat
3. Check compression again and perform a compression leak-down test to try to find a blown head gasket.
4. Pull the head off to inspect the head gasket and check for debris in the cooling system.

What would you suggest?

What do you mean by cooling acting strange? Is the telltale cutting out? Ive looked at video but I couldnt tell whether the telltale was stopping or it was the quality of video?

[dhaglund]

The telltale is fine. It's actually stronger than can be seen on the video. The "problem" that worries me is all the white smoke, and the lack of water coming from the exhaust. I think that it's steam and not exhaust smoke. If so, it isn't good. At planing speeds the smoke isn't there, or just not visible. The water and air temp is pretty cool in Sweden this time of year which makes hot gas even more visible. The engine is fully warmed up running fresh fuel with the correct amount of oil so I see no good reason for that much smoke from the exhaust.

Here is another video. Hit Shift-D when playing to download the video offline for better quality. But at the moment Google has some issues, so that isn't working. Perhaps in a while?
https://photos.app.goo.gl/mqd48eyKkBDCyTRx6

[A1an]

my next question was going to be what the air temperature was, I know on cold days some engines can really pump out the steam but it's just a trait of the exhaust system.

Have you taken a reading of the engine temperature with an infrared thermometer? I find these things great for getting a handle on what the real temps are. Don't trust the "touch" method if your hands are cold.

I think you might be worrying about nothing, its steam and not white smoke.

apologies if you've mentioned already but have you pulled the plugs on it? What colour are they? If you have a leak in to the combustion chamber one of the plugs is going to look like it's been steam cleaned.

[dhaglund]

The air temp that day was around 10 degrees C. So, not that cold.

I did check the engine block temp with an IR thermometer. The hottest place I could find was on top of the block right behind the pull start. The hottest temp I saw was 80 C in one spot. But that spot was normally around 74C. Temperatures on the back of the motor (cylinder head) was 62 - 65 C at the hottest places. This was with the hood off.

Spark plugs look ok. Not steam cleaned. Slightly dark and oily but that is probably from all the idling.

[A1an]

62-65 is on the money.