Cloud of Blue Smoke - Sudden - 522xi - Kohler

[Challenger 27]

This morning I was exercising my "winter" 522xi with 2 stage snowblower. I was just motoring around the lawn. At about 12 minutes at about 2/3 throttle the engine belched a major cloud of blue smoke. I truly was engulfed in smoke. I shut down immediately.

- No odd noises.

- Oil level is at full.

- Low hour machine.

- Temp gauge hadn't even come up much

- No oil showing on exterior of engine or within the engine compartment.

- Kohler 522xi twin.

I didn't try to restart. She's sitting on the lawn.

Any thoughts or ideas??? Should I just roll it on the trailer and take it to the dealer? I don't want to do any (more) damage.

Thanks.

- Challenger

[smoreau 658]

Sounds like you blew a head gasket. I had this happen on one of my ohv engines and it was due to too much heat in the engine compartment. Engine was spotless, but not enough air flow to the engine. It still started and ran fine, but it was like I was spraying for mosquitoes! after removing the head, it was blown to the push rod area of the gasket. It would suck oil in on the intake stroke and burn it power stroke. do a compression test to find what cylinder is blown.

[Challenger 27]

Thanks for you thoughts.

An update: When rechecking the oil dip stick I sniffed it. Just a faint hint of gas smell. Still "oily" consistency.

Any more comments?

- Challenger

[smoreau 658]

That sounds like its coming from the compression stroke pushing the air fuel mixture into the crank case. check compression first.

[Challenger 27]

Thanks.

Any thoughts on time needed (hours) for dealer mechanic to replace head gaskets? I'm not capable of doing this my self.

Thanks.

[Challenger 27]

What are potential causes of a blown head gasket? This tractor has never overheated. Only been run in the winter as a snow blower

Thanks.

- Challenger

[rmaynard 15,915]

Below is a pull quote from Brian Miller's web site concerning blown head gasket causes:

"Too lean of fuel mixture. This will happen if using a high speed fixed-jet Walbro carburetor above 3,200 rpm, especially during cool weather.

Worn throttle shaft. This will also happen if using a high speed fixed-jet Walbro carburetor despite the weather temperature.

Vacuum leak at carburetor mounting flange.

Over-advanced ignition timing."

[Hobby horses 99]

whats your oil level? if fuel has gotten into the crankcase they will blow smoke like that after running a bit...

[Challenger 27]

Oil level shows full on dip stick.

This happened very suddenly. Engine started and ran fine. Over the course of 10 minutes I brought from a fast idle to about 2/3 throttle. No smoke, no noises. Suddenly at about 12 minutes it was like a switch was thrown: HUGE cloud of thick blue smoke pouring out of the exhaust. Not a puff. It seemed like it would have continued full force if I hadn't shut- down immediately. Engine still sounded normal during the 2 0r 3 seconds to recognize problem and shut-down.

If it's fuel in the crankcase would that blow the head gasket suddenly or would this have evolved over some time?

- Challenger

[Hobby horses 99]

If fuel is in the crankcase it would show way overfull, after running, the oil and fuel would pass the rings and result in the big puff of smoke.... if your not over full i would say that's not it... even if that blew the head gasket you would still have all that gas in the crankcase and would still read over full.

[Challenger 27]

I just checked the dip stick one more time. It shows about a half inch overfull.

- Challenger

[smoreau 658]

Like I said before, Start with a compression test. Oil is getting into the combustion chamber and that is what is causing the blue smoke. If its not a blown head gasket, then you have a lot bigger problem. But from my experience and from my research of talking to others, it is common for them to blow a head gasket and blow blue smoke. When this happens, gas will get into the oil. it may or may not over fill the crank case. depends on how long it runs like that. Mine ran for about 20 min after it blew. I saw that it was over full on oil and had a strong gas smell to it. I changed the oil and it ran ok for about 3 min and started blowing smoke again like mad. At the time I couldn't come up with a reason for the problem. I pulled the head and the gasket was blown from the combustion chamber to the push rod part of the gasket. I changed the gasket and all has been good for over 250 hours. This engine was in my 1/3rd scale Ambulance I built for Junction Vally Railroad, and the intake fan to bring in fresh cool air had blown a fuse and it got too hot and blew. This will only happen on OHV engines. flat head engines this could never happen on.

[smoreau 658]

Head gaskets just don't blow all of a sudden. The head gets hot and warps a little, this takes some of the pressure off the gasket in between the head bolts. then combustion eats away the steel ring tell it buns a hole in it. then it doesn't take long after that for the rest of the gasket to blow out. I lean carb will cause this, or a vacuum leak. so if it is a head gasket. you need to find out what caused it to blow so it doesn't happen again. My issue was a blown fuse for my intake fan. Here is a pic of the ambulance I am talking about.

and the engine is in the back.

[Challenger 27]

Not to belabor the topic but could a head gasket be faulty when first installed at the factory?

This machine has only been run December through March as a snow blower. Fewer than 80 original hours.

- Challenger

[smoreau 658]

possible, but I wonder if old fuel could be the issue that caused the issue. slightly plugged carb, or wrongly tuned carb. You are using winter fuel when its working, and know you were driving it in summer. I wouldn't think that would be the issue, but it is a possibility. A head gasket is not only to seal the head to the block, but is also like a fuse before a major problem happens.

[Challenger 27]

Thank-you.