Help & Analysis: 1988 Johnson 6 HP 2 Stroke

[bnelson12]

Hi everyone,

I recently purchased a 1988 Johnson 6 HP 2 Stroke (j6rccs)

It runs & fires right up, however, it has brown stuff coming out into the water when running it.

I have attached pictures. You can see the brown material that is floating in the water, the red line that I drew which shows the water tube's path on the engine, as well as where the water tubing goes into the engine block. It looks like a mix of gas, oil, & water.

Has anyone had an engine similar to this where this was normal? Any ideas on what the issue might be?

My best guess was to replace the gaskets in the engine block anticipating there was a failed seal somewhere for gas & water

Many thanks for any expertise or insight!

Best,

Ben

 

[racerone]

This topic comes up often , too often.----I consider that normal for a 2 stroke.-----But perhaps check the thermostat.

 

[bnelson12]

This topic comes up often , too often.----I consider that normal for a 2 stroke.-----But perhaps check the thermostat.

When you say check the thermostat, could you explain? just to make sure I'm understanding - what do you mean by this & why would it be important? much appreciated

 

[racerone]

You need to install a new water pump impeller.------You also need about 6" ( 15 cm ) more water in your test bucket.

 

[bnelson12]

You need to install a new water pump impeller.------You also need about 6" ( 15 cm ) of water in your test bucket.

Much appreciated. How does a potential water pump issue correlate to the brown foam in the water?

 

[racerone]

Sorry----This stuff in the water is normal.-----YOU need to install a new impeller.----Reason is that this motor does NOT have a " warning " system for overheat.----And the motor does NOT have a " shutdown " system in case of overheat.-----Motor will run until it is too late !

 

[James6]

And you NEED to get the lower unit deeper in the water at least 6 inches above the waterpump

 

[bnelson12]

Sorry----This stuff in the water is normal.-----YOU need to install a new impeller.----Reason is that this motor does NOT have a " warning " system for overheat.----And the motor does NOT have a " shutdown " system in case of overheat.-----Motor will run until it is too late !

That makes sense. What is a typical temperature for what the cylinders near the spark plugs should be? I might get a heat gun just to check as well

 

[bnelson12]

And you NEED to get the lower unit deeper in the water at least 6 inches above the waterpump

thanks James, I will make sure to do that from now on. for my understanding, why is this critical?

 

[tphoyt]

Any new to you motor needs a water pump impeller at the very least so you know for sure it going to be ok and sometimes things wear out and the whole pump kit is needed. Also it’s a good idea to change the oil in the lower unit including the washers on the drain and fill plugs.
Pumps are not self primping so they need to be completely submerged. That’s the reason for the high water level.
Unburned fuel and oil is what your seeing in the water and is normal to some extent. Your photo looks normal.
140 for a temp is common.
You can test your thermostat by putting it in boiling water to see if it opens. In my eyes if your going to pull and replace the gasket you may as well toss in a new one but that’s just me.
Best

 

[bnelson12]

Any new to you motor needs a water pump impeller at the very least so you know for sure it going to be ok and sometimes things wear out and the whole pump kit is needed. Also it’s a good idea to change the oil in the lower unit including the washers on the drain and fill plugs.
Pumps are not self primping so they need to be completely submerged. That’s the reason for the high water level.
Unburned fuel and oil is what your seeing in the water and is normal to some extent. Your photo looks normal.
140 for a temp is common.
You can test your thermostat by putting it in boiling water to see if it opens. In my eyes if your going to pull and replace the gasket you may as well toss in a new one but that’s just me.
Best

Tphoyt,

Thanks for the detail on the pump kit and temperature. both make sense. I'm going to order a new kit to be safe.

On the thermostat side, what do you mean by test it in boiling water? I am a rookie here - where would I find the thermostat in the motor? didn't even know I had one.

Thanks again. Learning a lot from everyone here

 

[Crosbyman]

put the thermostat body (no gasket) in a pan and overfill it with water.
put in a cooking thermometer and slowly heat the water till the thermostat visually begins to open.
temp. should be around 140F it must close when cooling down

from the Net....
Put the thermostat in a bowl and immerse it in boiling water. As the thermostat heats up, it should open. When you remove it from the boiling water, allow it to cool and it should close again. If the thermostat remains open or closed, it has failed and must be replaced.

 

[Crosbyman]

see parts....

 

[hardwater fisherman]

thanks James, I will make sure to do that from now on. for my understanding, why is this critical?

The water pump is not self priming so you need to have the pump submerged on start up.

 

[bnelson12]

Hey everyone, I got a look at the motor again yesterday and noticed this on the lower unit:



Assuming it's just the gasket that is leaking? Any thoughts on how this contributed to the above oily water at all?

 

[Crosbyman]

2 strokes probably flush out 30-50% of the incoming fuel oil mix while in and out ports are open on the piston down stroke... it goes out and down the exhaust and liquifies residues along with carbon.... result ... oily water

do seaches on SLUDGE ....

 

[bnelson12]

2 strokes probably flush out 30-50% of the incoming fuel oil mix while in and out ports are open on the piston down stroke... it goes out and down the exhaust and liquifies residues along with carbon.... result ... oily water

do seaches on SLUDGE ....

Crosbyman - was this in response to the picture I posted of the oil leaking out of the lower unit or just a general thought? Making sure I am understanding this within context. Thanks!

 

[racerone]

Sorry but,-----How many times do you need to read that this is normal on a 2 stroke ?----And there is no gasket at that joint either.

 

[bnelson12]

Sorry but,-----How many times do you need to read that this is normal on a 2 stroke ?----And there is no gasket at that joint either.

I am new to outboards, racerone, so just clarifying to make sure I understand. I can't always tell which comment is related to which questions since I am a rookie to begin with. I appreciate your help!

 

[bnelson12]

I am new to outboards, racerone, so just clarifying to make sure I understand. I can't always tell which comment is related to which questions since I am a rookie to begin with. I appreciate your help!

so in reality that oil leaking out the top of the lower unit is likely nothing to worry about. again just clarifying how I am interpreting the message board. thanks again