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2003 yamaha 25 four stroke blowing oil out of prop

A

apocalapsi

New member
Hi, I hope someone can give me advice. I bought ny friends boat pulled
It out of storage. We ran the boat,it starts fine idles fine and runs at full power beautifully.
However, at idle in neutral if I give it a stab of gas it shoots out some black oil droplets from the prop.The lower end oil is clean
And the oil level is good. He told me it could be from fogging or storage and it needs a good run.
I already ran it a half hour and still the same.... At idle nothing shoots out but give it some gas and
shoots out done black oil droplets...could it be dirty carbs or anything else... I tried some carb cleaner
And it still did it..Any advice would be great
Thanks
 
Is it using any oil? It could just be carbon from the exhaust system. You could try running some Seafoam or Ringfree etc through it and see if that helps, and as your friend says, give it a good hard run.
 
aliboy said:
Is it using any oil? It could just be carbon from the exhaust system. You could try running some Seafoam or Ringfree etc through it and see if that helps, and as your friend says, give it a good hard run.
Click to expand...

No I don't think so....I'm just wondering if it could be something serious or is it normal.
I have never had a four stroke before so I don't know..could it be from trolling too long
Maybe its running rich and its blowing off excess oil?
 
You didn't say how long it was stored. It could be that the "fogging" was excessive and now you have gunk in the ring grooves. This may have made the rings sticky so you are also blowing by as you blip the throttle. I would try some cylinder cleaner to loosen the rings then make sure your gas is good fresh high octane grade. (not pre mix??) I freed up a two cycle motor with this issue by taking out the plugs, squirting cleaner in the bores then connecting an electric drill to the flywheel nut, a good 10 mins spinning usually loosen's things off. Make sure the ignition is off!!
 
vsixyb said:
You didn't say how long it was stored. It could be that the "fogging" was excessive and now you have gunk in the ring grooves. This may have made the rings sticky so you are also blowing by as you blip the throttle. I would try some cylinder cleaner to loosen the rings then make sure your gas is good fresh high octane grade. (not pre mix??) I freed up a two cycle motor with this issue by taking out the plugs, squirting cleaner in the bores then connecting an electric drill to the flywheel nut, a good 10 mins spinning usually loosen's things off. Make sure the ignition is off!!
Click to expand...

It was stored for at least a season possibly two... Whats curious is when I look at the oil level it looks like its above where it should be and secondly it looks less viscous than normal oil should look like. I'd swear there is gas in there but I'm not sure... Any idea how gas would get into the oil and if this is what is causing my black droplets problem...
 
I'd say the best course of action is to drain all the engine oil/filter and start again with a good recommended type. It is possible that "If" the fuel pump diaphragm is ruptured you could be getting traces of gas in the crank case. Check the condition and replace anyway. Record the level before and after first start. Note the colour of the oil.

I don't know about aditives but many owners use them, i haven't yet but may try a fuel system tonic.

The black droplets may be carbon residue from the exhaust cavities and will either remain or burn off. The "Right" oil is important and there are a lot of opinions on the forum. If you are not "losing" oil i would suggest it's carbon residue. Maybe a good long WOT run will help!
 
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