No temp alarm. CO2 detector went off, as it was started in cold warehouse. Pump was used to drain block of anti-freeze. Turned capt call on and then off. Neither position made a difference. Did not see hose getting sucked up or collapsing. Odd thing was, it was both engines at different times. So, shop thought unlikely for both impellers to be out.

I replace the impellers every year regardless......60-70 bucks is worth the piece of mind.

Water will flow from hose presure without impellors installed. I don't have any more suggestions for you though. Good luck.

Sometimes the impellors have a problem with the coolant that was put in when they were winterized. You may have to open up the blue drains by the impellor housings and let the water flush out the coolant.

All great feedback and suggestions. Will keep on "flushing out" this situation when I go to get the boat. No pun intended....

Thanks guys.

How were they winterized? (With antifreeze run through the system, or just pumped the air out?) If you just pumped out the air, you have to hit the release valve on top of the forward SB side of the motor to release the air pressure so water can displace the air.

Were the belts loosened? (Some shops do this.)

REGARDLESS, if you ran with no water coming out he exhaust for 25 seconds, you need to replace the impellers. Even if you have good water pressure eventually, you have weakened the impellers' integrity, and you need new ones. Better now, than in the middle of the lake on 4th of July weekend.

I've said it before, and I'll say it again. EAR MUFFS SUCK for flushing motors/hose starts. You need to have fresh water flush fittings plumbed into the sea water side of the cooling system. This is THE BEST way to use a garden hose and fire your motor, bar none.

Check the angle that your hose goes into the muffs. I used to use the muffs made by Merc. They were the type with the pin that goes thru the inlet holes. The hose inlet on those muffs was posititioned at a 45 degree angle. If the muffs were installed with the hose pointed towards to front of the boat, no water would enter the inlet and it would all spill out the muffs. I had to make sure that the hose was pointed towards the prop.

Thanks. It was a merc muff with the rod that slides through the drive. Hose did not seem kinked and was parallel to the transom. Water was coming out from around the muffs. Boat has not given a problem in the past. I think it was last run in late September.

I'm thinking Brian is right. You probably need to take the air pressure off the heat exchanger by "popping" the valve off. That would definitely cause your issue and cause water to enter the bilge while you were trying to flush it out.

you guys already have it, I think, Take off air pressure, if you ran it much without doing that, you might as well replace impellers as well , to save a breakdown on the water