Mercruiser ran w/o water!

[Big D]

I test ran my(with earmuffs) 1989 3.0 mercruiser i/o for about 2 minutes before noticing that the garden hose was crimped and the motor was dry! I immedietly corrected the water flow and after a little bit of steam everything appeared normal. Question, should this cause any concerns?

 

[12Footer]

Re: Mercruiser ran w/o water!

Imediately putting coolant to a superheated<br />block is death to most engines. You may have lucked-out,but keep an eye on your oil for signs of water (warped head/Cracked block).<br />Do not take the boat out without changing out the impeller first. They are made of rubber, and quickly burn up when run dry. Even tho you have flow now, you mont for long.<br />It takes less than 20 seconds to shread one of these. The good news is, they are cheap and easy to get at on those engines. <br /><br />------------------<br />Time to change my tagline

 

[hohmanj]

Re: Mercruiser ran w/o water!

I did the same Darn thing last year !! I am on a well pump at the house & did not realize the power had gone off in the neighborhood...I sucked the holding tank dry & **** near started pulling water from the toilets before I realized..I checked my 5 minute old impeller to find it burned quite nicely...Check yours as well !!!<br /><br />Cap. SeaHag

 

[Big D]

Re: Mercruiser ran w/o water!

Appreciate the advice & info. I dropped the lower unit today and found the impellor slighty burnt and distorted. One more question-should there be a seal on the upper pump housing? All I noticed was a groove where the drive shaft passes through but there was no O ring in it. There was just a slinger ring on top of the housing.

 

[ODDD1]

Re: Mercruiser ran w/o water!

BigD years ago merc used a seal on top of the pump housing,found it didnt do much good and eliminated them....a rubber slinger is all you need. I wouldnt woory too much about the motor...you were only idling and motor was cold on startup...if you did run it long enough to hurt something the first thing usually damaged is the rubber exhaust boot inside the boat..wheh you restart it check it for splits/spraying water.