Posessed V?
 

So i just brought the V back home after taking it to work so that I could use the shop to replace the lower shift cable. Before towing her home I put on the flush rig and ran the engine until it came up to temp about 170, shut her down and took her home. I parked the boat in the driveway instead of the usual spot in the back yard because of the rain we have had ALL WEEK. SO I'm sitting there watching TV when I here what sounds like a car in the driveway. I go to check it out and its the V running! I jump in the boat look at the key, its in the off position. so I switch it to on and then off and she cuts off. I think she only ran for a minute or two tops, and the temp gauge only read about 80 degrees. So I let her sit for a minute hooked up the muffs and ran her to make sure my water pump wasn't shot. she came up to temp and held for 15 minutes. this time i turned off the batteries before leaving. Is it possessed or is there a logical explanation? :head:

Wonder if water in the switch could conduce enough for that to happen?

I have no idea why that engine started like that, but I'm willing to bet your impeller for your water pump has suffered serious damage. As little as 15 seconds is enough to destroy an impeller that's running dry. You might have had a little more time due to the fact you said you ran the engine at the shop.. so the inside housing was wet to start with..... but that only gains you a few extra seconds.

If you want to check the impeller without taking it apart, put the engine in water (tub, lake, river, whatever) and see if it pumps ok. Putting it on muffs isn't an accurate test since the water pressure in the hose provides extra pressure to help force the water through the engine. Look carefully at your tattletail and make sure that it's pumping ok.

Personally, I wouldn't take the chance... $24 for a new impeller is a lot cheaper than $2400 for a replacement engine. Spend the time and money and simply replace it. :head:

I will agree with the Key switch theory, replace or re-locate the switch and you be fine. Some of the newer SW will allow water to flow through it others do not. If re-locating it is not an option then install a new SW which permits water flow through it, you will clearly see the the hole with the key remove and holding up to a light.
I clearly observed this when I removed my old OMC switch and replaced it during my restoration.

You would figure either the kill, run or crank portion of the ignition would fail or act up but NOT ALL THREE at the same time!
I've seen tilt & trim raise and lower before with no one near the motor but never heard of that. It would drive me nuts till I to get it to recreate the problem again.
I got to agree with Destroyer, change the impeller too.

Obviously POSSESSED!

yup. posessed.

Well, possessed is not so bad when you think about it... it's better than re-possesssed anyday. :you:

Impeller is definitely gone ran it in a tub, no water exiting. Is this a DIY project?

Yes but there are a couple of little tricks to make it go smoother.
Last Mercruiser I fooled with was over 20 years ago and it was a 140. Seemed like you needed to have the foot engaged in reverse and something else I can't remember.
Let one of the other guys post suggestions to give you step by step info and what to do to make it easier.
Sorry I'm no more help than that.