Will test running high RPM on water hose cause damage to engine?

I do not have a water tub to test run my engine with. Will running the engine in gear and at high RPM on a water hose cause damage to the engine? If so, what are the possible damages?

Re: Will test running high RPM on water hose cause damage to engine?

I hear it will cause internal damage.
Your suppose rev it no more then 1500-2000 rpm.

Re: Will test running high RPM on water hose cause damage to engine?

Short periods of time(2-3 seconds) at high rpm will not hurt anything.Any longer and it can cause overheating.Your garden hose will not deliver enough water to keep it cool.Your hose might put out 15 -30 gal a minute.The lake or ocean can deliver BILLIONS of gallons.Just don't overdo it.J

Re: Will test running high RPM on water hose cause damage to engine?

The reason for not revving it beyond about 1500rpm with no load is to avoid thermal runaway. It is scary as the dickens and can result in pieces flying in all directions.

If you have ever seen a nice, new, multi-kilobux outboard explode you will understand.

Re: Will test running high RPM on water hose cause damage to engine?

+1 for JB. The reason for not running at high speed doesn't have to do with water supply, it has to do with high rpm in an unloaded condition.

Water hoses even at the 60 PSI of a well pump have enough volume to keep an outboard cool. However, without the load on the propeller, the powerhead and lower gear box will overspeed. When the design load is exceeded, the engine will start to disassemble itself.

I have witnessed the results of engines coming apart and IT WILL CAUSE GREAT BODILY HARM OR DEATH.

There really is no reason that you need to run an engine in gear out of water. If you want to see if your prop turns, rotate the flywheel by hand with the shifter in gear and THE IGNITION SWITCH IN OFF.

If this seems a bit harsh, it is meant to be. I see too many bodies from the results of accidents that could have been avoided if they used some common sense.

John

Re: Will test running high RPM on water hose cause damage to engine?

Thanks, very good to information to have!