Dry Start/ Dry Run

[countryguy1717]

I know it was stupid of me, but I had my inboard mercruiser 350 hooked up to the fake-a-lake, ran it for a few minutes. Then I turned the boat off, and the hose while I took care of some other things. Anyways I went back to the boat afterwards to run it again, started it. Did a few things in the boat probably 5 minutes... jumped out and realized I forgot to turn the hose back on. I immediately shut the boat off, temp was about 190. I let it sit for about 15 minutes while I turned the hose back on and started it back up, temp was about 160.

So now my question is this. I know its bad to dry run the boat. What do I need to look for? I'm assuming I need to change the impeller. I assume running it that long without water probably tore the rubber to pieces. Do I need to worry about small pieces going through the cooling system? Its dark now so I can't take the raw water pump apart to inspect it. Any chance the impeller is ok and I did no damage?

 

[achris]

If there are bits of the impeller missing, you need to find them. Also check (with a view to replacing) anything rubber in the exhaust path, including the shutters...

As for chances of there being no damage... 2... Slim and bucklies...

 

[countryguy1717]

If there are bits of the impeller missing, you need to find them. Also check (with a view to replacing) anything rubber in the exhaust path, including the shutters...

As for chances of there being no damage... 2... Slim and bucklies...

I wish I was more inboard mechanically inclined. So do I need to take off the thermostat and exhaust manifolds? if there are large pieces missing?

 

[bspeth]

Replace and inspect the impeller,and go from there.

 

[ktbarrentine]

If you find out that you are missing bits of the impeller, start looking in the inlet to the power steering cooler. Dont need to take off the manifolds, just the elbows going to the "Y" pipe, then look in the top of each inlet to the Y pipe at your shudders.

 

[Bondo]

I wish I was more inboard mechanically inclined. So do I need to take off the thermostat and exhaust manifolds? if there are large pieces missing?

Ayuh,.... Ya keep sayin' Inboard,... What drive are We talkin' 'bout,..??

If by chance ya got a Merc Alpha, I/O, 'n not an Inboard,...
When ya drop the lower unit to change out the impeller pump,...
Pull the hose off the T-stat housin', that comes from the impeller pump in the drive, 'n Back-flush that line, with the drive off,....
Chances are 99.9% of any missin' pieces will be recovered, that way,....

 

[countryguy1717]

Ayuh,.... Ya keep sayin' Inboard,... What drive are We talkin' 'bout,..??

If by chance ya got a Merc Alpha, I/O, 'n not an Inboard,...
When ya drop the lower unit to change out the impeller pump,...
Pull the hose off the T-stat housin', that comes from the impeller pump in the drive, 'n Back-flush that line, with the drive off,....
Chances are 99.9% of any missin' pieces will be recovered, that way,....

Its in inboard direct drive not an IO.

 

[countryguy1717]

So definitely shredded the impeller. Now I have a few more questions:

Ive never been great at puzzles... How do I know if I got all/most of the vanes from the impeller?

Now that its to shreds does it matter what way the vanes turn when I put in a new one?

Lots of pieces were in the pump itself, the rest I found in the hose that sends the water to the engine. About 3 inches past the hose that outflows the water from the pump there is sort of screen, the rest of the pieces I found jammed up against the screen. There is one piece that is clogging one of the holes that I cant get out, you can kind of see in the photos below. Do I need to go any further or will any other small pieces be flowed through the system?

 

[countryguy1717]

Also is the spring in the circulating pump hose supposed to be visible from both ends? I noticed some rust in the cooling system, the boat is a 97 but do you think this is an acceptable amount of rust? Or might I need to replace the circulating water pump? I didnt find anymore pieces of impeller when I was taking the hoses off.

 

[achris]

1997 makes it 17 years old. That is an acceptable level of rust in a salt water run open cooling system....

 

[countryguy1717]

1997 makes it 17 years old. That is an acceptable level of rust in a salt water run open cooling system....

It is a ski boat that to my knowledge hasn't been run in salt water... Do you think the current water pump is still good? It usually runs from 150-190 max. I just noticed because of shredding the impeller. Does it look like I got a majority of the impeller or should I insect further?

Also I think the t stat I replaced earlier this year was a 160 as per factory specs. Any benefit to maybe going to a 140?

 

[achris]

If the pump doesn't have any movement (in the bearing) or make any noises, it's fine. No benefit with a 140 over a 160. The engine is better off running at the warmer temp anyway. If you have the main large piece out, you shouldn't need to insect any further...

Chris.....

 

[countryguy1717]

If the pump doesn't have any movement (in the bearing) or make any noises, it's fine. No benefit with a 140 over a 160. The engine is better off running at the warmer temp anyway. If you have the main large piece out, you shouldn't need to insect any further...

Chris.....

Thanks Chris! Always to the rescue!