Gas in oil pan for INTEK 540 cc 18.5 hp

sjo

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I have a Husqvarna mower with an INTEK 540 cc 18.5 hp engine.
I changed the oil, oil filter, fuel filter, air filter 2 weeks ago, then ran it for 90 min cutting part of my lawn.
Went back a week later to cut the rest and the mower started but blew out clouds of white smoke and spit oil out of the muffler where the pipe goes into it.
I stopped the engine, let it cool down, drained the oil and noticed the oil was very fluid, lighter color, and smelled of gas. Checked the gas tank, empty.
I've checked the fuel started solenoid and that seems to click open/close when I turn the key.
Could it be the head gasket? Or something else? Any suggestions? thanks all.
 

Rivets

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Carb float needle and seat are not sealing properly. Time to clean and rebuild carb with new needle and seat.
 

sjo

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Carb float needle and seat are not sealing properly. Time to clean and rebuild carb with new needle and seat.
Would pulling on the fuel hose to replace the fuel filter cause this? I assume not, but I'm new to small engines.
 
Last edited:

Bertrrr

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Doubtful , it's most likely the carb float / needle valve not seating as Rivets said
 

sjo

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Ok, thanks for the info all. Time to dig into it..
 

Tiger Small Engine

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I have a Husqvarna mower with an INTEK 540 cc 18.5 hp engine.
I changed the oil, oil filter, fuel filter, air filter 2 weeks ago, then ran it for 90 min cutting part of my lawn.
Went back a week later to cut the rest and the mower started but blew out clouds of white smoke and spit oil out of the muffler where the pipe goes into it.
I stopped the engine, let it cool down, drained the oil and noticed the oil was very fluid, lighter color, and smelled of gas. Checked the gas tank, empty.
I've checked the fuel started solenoid and that seems to click open/close when I turn the key.
Could it be the head gasket? Or something else? Any suggestions? thanks all.
If it is a Nikki carburetor, more prone to have needle and seat and tiny o-ring problems, therefore leading to fuel getting into cylinder and mixing with engine oil. I hate Nikki carburetors.
 

slomo

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If it is a Nikki carburetor, more prone to have needle and seat and tiny o-ring problems, therefore leading to fuel getting into cylinder and mixing with engine oil. I hate Nikki carburetors.
I absolutely love Nikki's. People push a perfectly good mower to the curb or sell for pennies on the buck. Simple carb clean and some gaskets later. Ol' girl is running like a top.

Install an inline fuel shut off valve. Use it when not mowing.

Now fix your carb needle and seat as others stated.

Flip the carb over. Pressure test the needle and seat. Should hold 7spi for 30 mins straight.
 
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StarTech

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And you guys are forgetting that the sealing gasket which can have either included separate o-ring for the fuel transfer tube can be bad. The version of the gasket with a separate o-ring tends to have this o-ring to go bad. You can replace the float needle all day and still have fuel leakage until you replace the o-ring if the gasket on the right is one being used.

Here is both gaskets.
1714042998456.png1714042897989.png
 

sjo

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I absolutely love Nikki's. People push a perfectly good mower to the curb or sell for pennies on the buck. Simple carb clean and some gaskets later. Ol' girl is running like a top.

Install an inline fuel shut off valve. Use it when not mowing.

Now fix your carb needle and seat as others stated.

Flip the carb over. Pressure test the needle and seat. Should hold 7spi for 30 mins straight.
After this happened, i installed a cut off switch to the fuel line...
 

sjo

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Well, I'll pull out the carb, take it apart, and see what I have before I order parts.
 
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