Johnson 20 hp. Carburetor problem

[OFF SIDE]

I have a older Johnson 20 hp ,2 stroke outboard, think it's a 1987 model. The motor starts right up, takes a few minutes to warm up , lots of smoke from exhaust. The motor idles and runs but spurts sometimes blowing out smoke.
The carb was taken off last year and clean, however experiencing the same issue.
At the bottom, just below the cavitation plate oil is dripping out, I would assume its from the exhaust, but there's quite a bit.
I have adjusted the mixture running it in then backing it off 11/2 turns and less to one turn, still oil leak. Gas is mixed 50:1 using 91 octane. Lucas 2 stroke oil and Sea Foam added.
The carb shows model 398084 MX. I can't find any thing on this carb.
Any suggestions? Thanks

 

[racerone]

Is the thermostat in place and working properly ?----Might be suffering from the classic 2 stroke lean sneeze as well.

 

[OFF SIDE]

Is the thermostat in place and working properly ?----Might be suffering from the classic 2 stroke lean sneeze as well.

Yes, lots of water, gets a bit warm . I'm using the muffs.

 

[saltchuckmatt]

Explain your link and sync procedure.

 

[racerone]

Is the thermostat in place / not stuck open / working as designed ?

 

[Crosbyman]

it can't leak more oil than what is mixed at 50/1 concentrate on the carb, thermostat etc...


check ignition to make certain it fires OK otherwise it would dump raw unburnt full/oil in the exhaut housing washing out the lower section of accumulated carbon deposits.

 

[OFF SIDE]

Tks everyone. I'll start by checking the thermostat , go from there

 

[OFF SIDE]

Ordered the thermostat. Here's what's it's doing

View attachment 20240611_151709.mp4

 

[racerone]

That is the classic lean sneeze.------Idle mixture is too lean .----Or throttle plate is opening too soon.

 

[saltchuckmatt]

Link and sync is not correct. Move the cam 1/4 to 1/2 inch forward of the lines.

 

[jimmbo]

I have a older Johnson 20 hp ,2 stroke outboard, think it's a 1987 model. The motor starts right up, takes a few minutes to warm up , lots of smoke from exhaust. The motor idles and runs but spurts sometimes blowing out smoke.
The carb was taken off last year and clean, however experiencing the same issue.
At the bottom, just below the cavitation plate oil is dripping out, I would assume its from the exhaust, but there's quite a bit.
I have adjusted the mixture running it in then backing it off 11/2 turns and less to one turn, still oil leak. Gas is mixed 50:1 using 91 octane. Lucas 2 stroke oil and Sea Foam added.
The carb shows model 398084 MX. I can't find any thing on this carb.
Any suggestions? Thanks

Is this 'Lucas Oil' a TCW-3 Oil?
Why are you adding SeaFoam to the Gas, there are much better Snake Oils you can use?
As for the Oil you see on the Gearcase, have you smelled it? If it smells like Gas. it is likely unburnt Gas and Oil, but it reeks to High Heaven, it would likely be Gear Oil, and the Gearcase would need a Reseal doen

 

[flyingscott]

open the low speed screw another 1/4 turn