On a recent ride a member of our party made a grab for a rare 'Water Badger' and unfortunately managed to fill his engine with muddy water! So what should you do and more important what not to do. If your engine was running and went under then its probably sucked water into the cylinder. When you try and restart the engine this water will stop the engine turning over because it cannot be compressed. At this point STOP and get the tools out, dont try and bump start it down a hill or force the kickstart. You could cause expensive damage if you do. If theres enough people around its not a bad idea to lift the front of the bike up high to empty any water from the exhaust if not you could lay it on its side. 1. Remove the sparkplug (often only after taking off the fuel tank) also a good idea to have a look at the air filter at this point and ring it out/shake any water out of it. 2.Crank/kickstart the bike with the plug out untill any water has come out. It will come out with quite a force so dont be looking in the plug hole! 3.Its also a good idea to drain the float bowl on the carb, this can be done by undoing the big bolt on the bottom of the carb or even easier on a lot of bikes there is a small screw/allen bolt with a drain pipe on it. Either way let the fuel flow through a bit to get any water out. 4.Put it all back together and she should be as good as new. Well as good as before you took a swim anyway.
If this has happened to a four stroke you may well find the water has found its way either past the piston or through the crankcase breather route via the front part of the airbox.If this has happened you will find that the oil has become emulsified( milky ,a bit like baileys).If this has happened change the oil and filter as soon as convenient .Running the oil in this state is bad for your engine.Often the water we ride through is muddy and contaminated.This has happened to me several times over the years.
So what should you do and more important what not to do.