Mercruiser cooling problem

J

jpopp

Cadet
Joined
Jul 16, 2003
Messages
15
Have 1985 Chris Craft with typical small block 350 and I believe an Alpha one outdrive. Went to start up boat after sitting for winter. Drained antifreeze out and hooked ears up to it. Motor started but would not take water up and started to smoke so turned it off. Poured water into exhaust hoses, hooked up ears and started again. Still didn't take water up or discharge water but was fine for awhile, but then started to smoke kind of bad out of exhaust ports it looked like. What is up, why won't it take water up, or discharge any water. Did discharge water as pouring in hoses I am assuming when I got too much in, it opened up the exhaust flaps.
 
O

outboardguy

Petty Officer 1st Class
Joined
Jan 16, 2004
Messages
262
Re: Mercruiser cooling problem

Check and replace your water pump impeller in your drive.
 
H

hondon

Lieutenant Commander
Joined
Jun 11, 2001
Messages
1,922
Re: Mercruiser cooling problem

That water pump impeller is a regular maintenance item .If you do'nt know when it was last changed,or if it ever has ,or you have had a dry run, you are way over due.A good place to start.
 
J

jpopp

Cadet
Joined
Jul 16, 2003
Messages
15
Re: Mercruiser cooling problem

Before ripping into impeller, would like to know if there really is problem. Temp gauge never climbed up, so assuming thermostat never opened to get water in. Is that right or should water be flowing through system all the time. Only water that came out of exhaust was when I was filling hoses with water. Plus, can't get to thermostat, bolts are seized up in housing, not quite sure what to do.
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Mercruiser cooling problem

For temperature gauge to show a reading, water must be around the sender. If there's no water in the system, then the only way the heat will get to the sender is as the block heats up. For enough heat to get up the water block (on the front of the engine) your motor would have to be red hot, quite literally glowing! If it's been in storage for a while and it's not pumping water the FIRST place to start is the impeller in the leg.<br /><br />The system is set up so water is pumped into the block (even if it's empty) and held there until it's hot enough to open the thermostat. <br /><br />Chris.........<br /><br />If you want a water flow diagram, let me know.
 
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