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ROS 125 oil dripping from manifold


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Looking for some advice if I may. I have a used ROS 125 and seems to start and function ok but I have noticed black oily substance coming from the exhaust manifold area, not a vast amount but there nonetheless, where the pipe bolts to the engine. It drips down onto the expansion area of the pipe but I can also see little streaks of black on the wooden prop. Can anyone advise what this may be and how to resolve if considered problematic?






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The exhaust manifold on my ROS125 has some kind of gray-colored rubbery sealant where it meets the engine. You can probably go to an auto shop and ask around for an. exhaust sealant. I would make sure that it doesn't set hard because it would make getting the exhaust off in the future very difficult.

If there's gunk it probably means that you're running too much oil or too rich. Check the spark plug to make sure it's the right color.

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20 hours ago, Capotec2015 said:

Thanks again for the advice -doesnt look like there's any sealant on mine - what mixture are you using per 5 litres-I might be running too much oil...

The manual says 50:1 after you have already broken in the engine, 40:1 if you are still in the break in period. Just check the spark plug and if it's black you're running rich.

If your engine is already broken in you would use 100mL for every 5L of fuel for a 50:1 ratio 

5000 mL petrol * (1 mL oil / 50 mL petrol) = 100 mL oil

I just use the pump at a petrol station to precisely fill my tank and then squirt or pour in the correct amount of oil using a measuring cup or syringe.

Image of spark plug colors attached.


Edited by fuzzybabybunny
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