Heavy white smoke

[Anonymous]

Our Rotax 125 puts out quite a bit of white smoke, even while running at speed on the track.

What’s the likely cause, can it be fixed, should we worry?

Thanks.

[Anonymous]

Normally 2 strokes due put out quite a bit of smoke but if it’s really thick you might want to try to lean out your jetting. Your experiencing a rich condition which could cause a lack of power. I’m not real familiar with the rotax motors but I believe a lot of guys who run those motors have a program called max jet which will help you determine the appropriate jetting for the current weather conditions. If your not into the whole computer thing old fashion trial and error is going to have to do.

[Anonymous]

I did a little research and found this article. Not sure if it will help but here you go.

http://www.accelerationkarting.com/etuning.html

[Doug Welch]

Smoke after the kart is at speed is NOT normal. It is possible the jetting is way too rich. Do you know what your current jetting is? You should have a main jet of 160 in it at these colder temps. If your jetting is correct, the next thing to check is the amount of oil in the mix. The Rotax should be at 33 to 1. Do you shake your fuel tank after it has been sitting? Most oils, particularly caster oils, will separate from the gas particularly at these cooler temps and you will get a heavy dose of oil at start up. Before running your kart, shake it vigorously to mix the gas/oil. If you are using a castor oil, switch to Motul 800 synthetic. It will stay in suspension better.

If it still smokes after all this, it most likely is a water leak of some sort. Have you checked your water level in the rad? Does it go down over the course of the day?

[Anonymous]

Thanks, Doug–I’ll start checking the things you mentioned.

[Anonymous]

@jasonbenoit02 wrote:

I did a little research and found this article. Not sure if it will help but here you go.

http://www.accelerationkarting.com/etuning.html

Also, good info, thank you!

[Marc Elliott]

Go with Doug on this one…
It very well likely you have a water leak in the head or through the cases. I have seen this before on a few different engines.
Peace-Marc

[cgordon]

Make sure you didn’t forget to turn the choke off.

Charles

[Gary Meadors]

White smoke is an indication of water in the combustion chamber. More than likely you blew a head gasket and water is getting into the chamber. Check the water in the radiator, if it is white or foamy that would also indicate a blown head gasket. If it isn’t the gasket, then you have a crack in the head or cylinder wall.

With any luck it is just the head gasket.

[Garrick Mitchell]

Ditto the other replies suggesting water as the culprit. White smoke out the exhaust is quite different from our beloved 2-stroke oil smoke and is a pretty strong telltale of water getting into the combustion chamber. If you’re running something air-cooled, though… 😯 !

[Rodney Ebersole]

It has been a little cold out side?

[Anonymous]

Clean fuel with new oil, well-mixed at the correct proportion seems to have diminished the smoke considerably after the engine’s up to speed.

Next up: Switch carb jet.

I’m thinking water’s not leaking into the combustion chamber. Fortunately.

Thanks for the advice, all.

[Rick Schmidt]

What main jet is in it?

[Author]

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