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Stupid mistake

  • Thread starter desperate to fish
  • Start date
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desperate to fish

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"Can anyone please help? I hav

"Can anyone please help? I have a johnson 78 / 85 hp. My brother in-law filled up the petrol tank for me and put in lawn mower oil.
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. The motor has run on it for about 2 hours. It now only idles on full throttle and the one spark plug keeps burning black and thick black oil comes out the exhaust. Any ideas or reccomendations would be appreciated. Desperate????"
 
What do you mean by he used la

What do you mean by he used lawn mower oil? Are you saying that he used four stroke oil instead of two stroke oil?
 
"Drain the fuel system and fil

"Drain the fuel system and fill with correct mix!
Try to de-carb (Sea foam, engine tuner) the engine. Hopefully Your rings etc have survived!"
 
"No, it was not 4 stroke oil,

"No, it was not 4 stroke oil, it was 2 stroke but the container says its for lawnmowers etc. (land based motors).

I have drained the fuel system and am now using the proper marine oil in the fuel.

To be honest, I'm not even sure if the oil is the problem, it may just be a coincidence, but since then it does not want to idle without the choke open full (and it doesn't run smoothly). And of course there's the 'oil out the exhaust' issue too!"
 
"Should not be too big a probl

"Should not be too big a problem when it comes to the oil. If running on land on hose, it is normal whith some desolved carbon/oil/soot comming out of the exhaust.
Do as I suggested: a de-carb. Then out for a ride and if possible post a pic of the sparks.
(Fouled down plugs may be a flooding carb.)"
 
Thanks Morten will try that an

Thanks Morten will try that and post a pic tomorrow.
 
"Engine oil for a two stroke o

"Engine oil for a two stroke outboard is fine. The first 2 strokes didnt have super 2 stroke oils. The difference between outboard and aircooled 2 stroke oil is also is pretty minimal.
A mate of mine run B47 engine oil in Suzuki trail bike for years. No probs.
I ran super outboard oil in aircooled rotax it outlasted the engines with so called correct oil.
You may have a a stuck or broken rings, hole in piston, scored bore.

ted"
 
"Ditto what Mr. Heath said. F

"Ditto what Mr. Heath said. For prolonged use I would stick to a marine oil with the proper TCW rating. Highly unlikely the oil your friend used would cause any damage, much less so quickly."
 
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