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View Full Version : On dewinterizing, impellers and freeze plugs....


Knoxes
05-09-2005, 10:51 AM
On it's first start since September, my 88 PS190 started right up, but I noticed there wasn't any water coming out of the exhaust, so I replaced the impeller, which was basically shredded. When I restarted it, two freeze plugs blew out. I'm pretty sure I did a good job draining the water out this past fall. Is there any other reason why they would come out, other than the block freezing up this winter? I'm in NC, and we had a pretty mild winter this year.

Engine Nut
05-09-2005, 02:16 PM
On it's first start since September, my 88 PS190 started right up, but I noticed there wasn't any water coming out of the exhaust, so I replaced the impeller, which was basically shredded. When I restarted it, two freeze plugs blew out. I'm pretty sure I did a good job draining the water out this past fall. Is there any other reason why they would come out, other than the block freezing up this winter? I'm in NC, and we had a pretty mild winter this year.

The core plugs for a marine engine are brass so they don't corrode. Typically, the only thing that pushes them out is the expansion of water when it freezes. It is critical when you drain the block to completely remove the petcocks if your engine has them, and take a piece of stiff wire and probe around through the drain holes in the block to make sure that no sand, rust scale or other debris is blocking the hole.

Notice that I referred to them as core plugs not freeze plugs. Those plugs are in the block to plug up the holes that are used to remove the core sand from the block at the foundry. They are not designed to protect the block from the expansion of freezing water. I have seen many of freeze damaged blocks with the core plugs intact.

Engine Nut

Ric
05-09-2005, 05:19 PM
Knoxes, where thehellhave ya been?