confession and question: impeller hardiness

[adornato]

Last weekend, i changed the SIX pencil zincs on my little yanmar 4LHA-STP after
closing the raw water seacock.
My old usual practice on prev boats was to take the ignition key and place it on the seacock so i would remember to open before starting the engine.
BUT the Yanmar has no ignition key and i was too lazy to find some blue tape to put on the start switch sooooo...
I ran the engine less than 5 minutes at idle before i thought to check the exhaust outflow and then zingo it hit me and i turned off the engine. I then used the boat that day for about an hour in the bay and all seemed ok.
The question is: did I shorten the life of my impeller drastically and should i change the impeller before i launch on a 25 mile offshore fishing trip next week?

and maybe now i will get around to installing the exhaust water flow alarm i bought last year.

 

[DavidM]

I don't think the engine overheated during 5 minutes of idling with no raw water flow. Lots of mass to heat up with little heat input at idle. Nor do I think you damaged the exhaust hose or lift muffler. A diesel sucks a lot of air while idling but burns just enough fuel to keep it turning over so the exhaust stays cool.

But you could have damaged the raw water impeller by running dry for 5 minutes. I would change it out before heading offshore.

David

 

[psneeld]

Most of the engine should be fine, but yes I would change the ompeller.

 

[Cigatoo]

I would change it, if only so you sleep at night. However if you used an OEM Yanmar impeller I bet you find it in good shape. They are pretty tough.

 

[Shrew]

For the cost of an impellor?? Change it.