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Subject: Gas in the crankcase?

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Tom S.    Posted 05-06-2018 at 15:39:08 [URL] [DELETE]        [Reply] [Email]  
  • Gas in the crankcase?
  • We bought a 49 8N a few months ago and it's been running well since then (maybe 8-10 hours total). Started fine. My only complaint would be that its power was only so-so, though it did okay if we kept it in first or second - moving rocks and gravel, pulling junk cars on a level surface. But just this morning I went out to start it and it wouldn't fire up. I smelled gas and figured it was flooded, so I came back a couple of hours later. I finally got it started, but it was misfiring and when I looked at the oil filler I saw it was spitting gas. I shut it down right away, and when I checked the oil there was gas on the dipstick. The only thing I did different was that I forgot to turn off the gas overnight.

    Is it likely the tractor's getting so much gas into the cylinders that it's leaking down around the rings into the crankcase?

    Any thoughts would be appreciated.

    Kirk-NJ    Posted 05-06-2018 at 17:32:57 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas in the crankcase?
  • Oil pressure should have been a dead give away.
    Hopefully you caught it in time.

    Bruce (VA)    Posted 05-06-2018 at 17:03:10 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas in the crankcase?
  • You have two problems.

    You forgot to turn the gas off (tip # 9) or the sediment bowl valve is bad, and you have a bad float, needle valve/seat or some trash causing it to stick.

    If you have gas in the oil, drain it, add new oil & change the filter.

    Then, make sure the sediment bowl valve works. With the gas turned off, remove the fuel line from the carb & put a bucket under it. If you find gas in the bucket after 24 hours, the valve is bad. If not, it was operator error! :) Turn the gas off.

    You also have a sticking float or bad needle valve or seat in the carb.

    This is one of the things that can happen if oil gets in the gas:

    We just had an 8N in the shop that the owner wanted us to fix the carb leak and replace the starter because the engine wouldn"t turn over. Turns out the base had more gas in it than oil and the bearings didn"t get enough lube from the diluted oil and seized the engine. I think of that tractor every time I park my tractors now and don"t forget to shut the fuel off.

    (YT Post 10/10/07)

    Tom S.    Posted 05-07-2018 at 12:40:32 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas in the crankcase?
  • My family had tractors when I was a kid, but this is my first N. The guy I bought it from showed me how to turn the gas off and on, but I thought he was just doing that because the carb dripped gas. (We used to do that with our 600 Case.) I didn't know it's an essential thing to do every time when you're running an N.

    Got it now! Operator error indeed.


    Tyler (MD)    Posted 05-06-2018 at 16:35:51 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas in the crankcase?
  • Gas is leaking past the needle valve/seat in your carb and flowing through the intake into the engine. Need to fix the carb, drain the oil, check the air breather cup for gas also. Go ahead and replace the oil in that breather cup as well.

    Had the same thing happen to my 9N.

    Best not to forget to shut off the gas at the fuel shut off valve at your sediment bowl. This would have prevented your problem.


    Tom S.    Posted 05-07-2018 at 12:31:43 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas in the crankcase?
  • Thanks. I wouldn't have thought to change the oil in the air breather.

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