KA-CHEW!

[Willy]

I just took a couple mile trip each way to go pull my stepson's SUV from where he'd stuck it in his yard yesterday. About a 15min drive each way. I'd gone about 2/3s of the way home and was going downhill in 3rd, about 3/4 throttle, and heard a loud "KA-CHEW" from the left side of the engine with a puff of vapor coming from the oil breather area of the engine. Other than that no unusual noises and it kept running great like it always does, so I headed on to the shop and parked it in it's "stall". Just the one time and it sounded like a bunch of pressure being released is the best I can describe it.

The only thing I can think of is the oil breather being clogged up and the noise and vapor was it's relieving pressure from the crankcase. I think I'm going to see if I can clean it out in a coffee can of kerosene.

But, I'd sure like to hear any other ideas of what the KA-CHEW was.

Willy

PS: Almost stuck the Cub trying to pull that SUV and sure tore his yard up doing it. But once Lil Red started pulling that Nissan, I sure wasn't letting up until I got both on solid ground.

[Willy]

Got the breather cleaned out (it was kind of nasty) and changed the oil and filter while I was at as it still had the oil in it from when I first started it up about a month ago. I'm pretty sure that the breather was clogged up.

[jsfarmall]

I'm sure the breather had a little to do with it but sounds to me like it was due to higher rpms with a "reverse" load on the engine and caused a bit of a backfire through the intake. Instead of the engine pulling the tractor, the tractor pulling the engine from going downhill. I'm not in the hills but there is a river levee real close. I have occasionally had something like you described but not quite as bad as you described.

[Matt Kirsch]

Normally coasting down the hill you'll get backfires out the exhaust on an otherwise normally operating tractor. I've seen some pretty impressive fireballs from our Super M over the years due to this.

Your engine almost certainly has some blowby/leakage past the rings, and the backfire partially ended up in the crankcase, where it would naturally come out the breather.

[John *.?-!.* cub owner]

Normally coasting down the hill you'll get backfires out the exhaust on an otherwise normally operating tractor. I've seen some pretty impressive fireballs from our Super M over the years due to this.

Your engine almost certainly has some blowby/leakage past the rings, and the backfire partially ended up in the crankcase, where it would naturally come out the breather.

I think Matt has the correct idea. I used to think it was fun to sut off ignition switch for a few seconds when going downhill with a hot engine and turn it back on to sometimes get a backfire. Then I started wondering what would happen if that rusty muffler about 3 feet in front of my face blew apart with the backfire. I am not real pretty as it is, and did NOT want to make it any worse.

[Willy]

Thanks for the replies. I would be surprised if there wasn't some blowby/leakage still considering how long it's sat since 2005 without being run but about an hour in 2012. I still get a little smoke on startup that quickly clears up.

[Urbish]

I used to think it was fun to sut off ignition switch for a few seconds when going downhill with a hot engine and turn it back on to sometimes get a backfire. Then I started wondering what would happen if that rusty muffler about 3 feet in front of my face blew apart with the backfire. I am not real pretty as it is, and did NOT want to make it any worse.