Blowing fuel from carb

DiamondCuts

DiamondCuts

Forum Newbie
New to the forum, I have a lawn boy s21bsn I picked up for $40. The question I have is... It runs great starts 1st pull but it will some times blow fuels out the carb it is missing the air filter I don't know if that might why? Cleaned muffler and carb.
 
The first thing I'd check is the float valve. If there's even a tiny bit of dirt there or the valve is worn, it won't be able to stop the flow of gas.

P.S. -- it's a bad idea to run any gas engine without an air filter.
 
I soaked the carb in cleaner, I am debating on getting a new carb. I know the air filter is vital, seems every mower I get from c list is missing the filters. I just want to get this mower in 100% shape I have a 4 stroke lawn boy I use in my business and you can't get a better cutting or bagging mower. Other thing I run echo red armor oil in every thing 2 stroke I have at 50:1 will it harm the mower to run it at 50:1 with the quality oil of today, or just stick at 32:1 ?
 
I've been using fuel mixed at 50:1 in all my two-stroke equipment (including one LB that gets a lot of hours) for years without a problem. The technology of two-cycle oil has improved a lot in the last 20 years or so.

But not everybody agrees with me. The fuel mix debate, I'm convinced, will go on as long as the internet exists and beyond. :confused2:

If you search this forum for something like "gas/oil mix" you will probably find so many posts that your eyes will cross before you can finish them. :laughing:
 
On the original question... have you checked the float valve? If the float is in the up position, you shouldn't be able to blow air through the fuel inlet. I wouldn't buy a whole new carb until I made sure that the problem isn't just the float valve (it's much cheaper and is usually included in a carb rebuild kit.)
 
DiamondCuts said:
New to the forum, I have a lawn boy s21bsn I picked up for $40. The question I have is... It runs great starts 1st pull but it will some times blow fuels out the carb it is missing the air filter I don't know if that might why? Cleaned muffler and carb.
Click to expand...
A little bit of fuel is ok.
 
I checked it when I had it apart and it seamed fine, I'm going to run it this weekend and monitor it. I had looked into the fuel mix before and it made my brain hurt, I'm run 50:1 and if I does ever blow I have a spare short block
 
You can buy the needle,float, and valve for 12.00. Then you should not have a flooding issue. The needle and valve can corrode causing it to not seat.

50 to 1 should be fine. One thing is that LB 2-strokes run hot. There is an argument by using 50 to 1 will give you a slightly richer mixture which will be cooler than at 32 to 1.
 
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