"JT" wrote in message
ups.com...
| Hello All,
|
| I recently purchased a boat with a ~1986 Mercruiser 170 (inline 4). It
| ran fine and cool when tested before purchase.
|
| Now that I have it home, I fired it up for the first time in the yard.
| It fired fine and ran smooth, but started to overheat within about a
| minute or so. I turned it off before it reached 200. I noticed that it
| was not outputting any water out from the gimble area of the outdrive.
| When tested before purchase, there was significant water coming from
| that area.
|
| This leads me to belive that the raw water pump in the outdrive is not
| functioning properly. To test this theory I disconnected the hose
| leading from the outdrive from the heat exchanger. I then restarted
| the engine and let it run for about 30 seconds. No water came fom the
| hose.
|
| This still leads me to believe that it is the outdrive water pump. Odd
| thing is, the seller told me that the water pump had recently been
| rebuilt. He even commented during the pre-purchase how good the outlet
| flow was, and I agreed.
|
| So I guess my question is... if I am not getting water from the hose
| into the heat exchanger, is it definitely the water pump? Can the
| voltage regulator interfere with the flow? (it is between the outdrive
| and the exchanger). Is there any other way to test the raw water
| pump?
|
| BTW, I did check the water inlet area of the outdrive and it looks
| clean. The earmuffs are making good contact and there is good water
| pressure from the hose.
|
| Thank you for your assisatnce!
|
| John
|
Did anyone run the engine without the water supply? It only takes a few
seconds to destroy the impeller.