Gas in oil

[Bilge Rat]

I have 3 riding mowers that have some gas in the oil.
They have sat over the winter and now the oil level is about 1" higher on the stick and smells of gas.
All are gravity fed from the fuel tank.
All have the Nikki carb on them with the fuel cutoff in the bowl.
2 Kohler 19 hp. and 1 Briggs 20 hp.

Anyone else seeing this?

I think the fuel cutoff is leaking over time and with south Georgia heat coupled with the pressure sealed tanks gas is being pushed into the motor.

 

[Stevetheboatguy]

Just put one of these on for my neighbor who was having the same issue.

Well actually I put a valve in and clipped the epa duckbill in the cap so now it can vent out a bit.

Steven

 

[Bilge Rat]

I buy those by the dozen.
Yes i add them with a new fuel filter.
Customers forget to use them.
I hate changing oil because of gas fouling

I have 2 mowers, Cub Cadets that were started this year that smoked after they warmed up.One belched white smoke.
Both have only 50 hours on them.
Hoping they have not chewed up the motor guts.

 

[Bilge Rat]

Customers just run them and park them with no care.

 

[JoeDirt]

I've dealt with this more than a few times. The problem is with the needle and seat. The needle leaks and dumps fuel while it sits. The shut off valve will work but the to really fix the problem you have to replace the needle and seat. The problem is not exclusive to Nikkis, it happens with Walbros too, but it seems to be more common on the Nikkis.

I hate Nikki carburetors.

 

[Bilge Rat]

The thing checks good for a minute but with all the plastic parts swelling, shrinking etc. with heating/cooling anything is possible.

Yes i don't like the Nikki carbs either.
They are not cheap to replace and the plastic parts costs about 3/4 of replacement.