Vented Loop - Bypass valve possible?

[sinnerman]

Standard operating procedure is to close the raw water intake when cranking the engine for extended periods of time.

If not, you can fill the water muffler with water (as without the engine running there is no "exhaust" to push the water out....)

Once the muffler fills, you run the chance of water backing up into the engine and filling the cylinder(s) with water as the exhaust valves open.

This is called "hydrolocking" and ends up mechanically damaging the engine.

The same can happen on some boats when sailing on a heel. Water in the muffler can get back into the engine.

Most mufflers come with a drain plug to remove water from the muffler (and to provide a way of draining it for "winterizing".)


Cranking the engine for a reasonable amount of time with no raw water will not hurt the impeller.

My two cents

Cheers