over heating

karatejoe

Seaman
Joined
Apr 30, 2010
Messages
59
I just purchased a 1986 Chaparral 215 with mercruiser Alpha 1 drive. On the test ride prior to purchase the engine temp was fine. Engine ran great. We dropped the boat off at the ramp where I was going to drive it to my house. I have a place with a boat lift on the canals. It was low tide. Its the Gulf side so tide gets very low. Just under 2 feet. I left the ramp and should have turned left but went straight. straight in to 1.5 feet of water. I slammed it in reverse and dredged out of it. I got stuck once again in front of my dock. its really low at low tide. I shut it down and waited 4 hours for high tide. The temp. was fine on my trip home.
Now The engine overheats. I tried flushing it but no help. I pulled the hoses from the top of the motor and flushed them and water comes out by the out drive like it should. I checked the thermostat in boiling water and it opens and closes ok.
Is it possible the lower pump sucked up sand and mud and is clogged up? How do I back flush this? Im new to boats but know Auto engines very well but this cooling system is new to me?
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
Messages
62,321
Re: over heating

You need to check the impeller. If it was plugged up, it may have burned up from running dry.
 

karatejoe

Seaman
Joined
Apr 30, 2010
Messages
59
Re: over heating

How do I check the impeller? Would pulling the hoses off the thermostat houseing and running the engine prove if it was working or not?
Is it possible to back flush the lower pump or does it just get replaced?
 

Bondo

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Apr 17, 2002
Messages
71,079
Re: over heating

Would pulling the hoses off the thermostat houseing and running the engine prove if it was working or not?

Ayuh,... That'll tell you if it's workin' at All,...
In the Manuals, there's a time/ volume Test that works like that...

With the unknown History, the lower should be dropped,+ the impeller replaced..
 

karatejoe

Seaman
Joined
Apr 30, 2010
Messages
59
Re: over heating

Pulled the hoses and ran the test. No water flow at all. I will replace the impellar this week.
Any Idea what the lower half of the Alpha One drive unit weighs so I have an idea of what kind of muscle to have when I remove it?
Thanks for your previous input.
 

Bondo

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Staff member
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Apr 17, 2002
Messages
71,079
Re: over heating

Ayuh,... 40lbs.or so....
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: over heating

You might want to consider removing the complete drive then remove the upper. Many first timers have a lot of problems removing lower only when they try to put it back together. Make sure everything is in forward, hit the water tube, line up the splines, line up the shifter, don't loose the quad ring,
Just a thought.
 

karatejoe

Seaman
Joined
Apr 30, 2010
Messages
59
Re: over heating

replaced the lower pump today. The impellar was in about 40 pieces. Wasnt that bad since it was my first time to do one. I did it while it was on my boat lift. I Backed it on the lift and made a make - shift work station. Did the whole job 2 feet above water. Give or take a foot for changing tides.
Stupid manatee came splashing under my boat. Scared me to death as I thought it was a shark. ( everything is a shark until verified otherwise)
Anyway, Boat no longer over heats. I think the hardest part was getting the rubber pieces out of the bottom of the lower drive.
 

PitchFork

Petty Officer 1st Class
Joined
May 28, 2009
Messages
313
Re: over heating

( everything is a shark until verified otherwise)

No doubt!! I was snorkeling at Pensacola Beach with a friend and two Dolphins jumped right next to us and we hauled butt back to shore. Scared the H E double hockey sticks out of us.

Glad you got it working again. Their nothing like fixing a problem yourself and saving mucho dinero $$$

Happy Cinco de Mayo
 
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