Share on Facebook subscribe feed
13 Replies | Page 1 of 11 | Top of Page | Bottom of Page

Boat motor over heats.

by , Posted to on 12/19/2011 8:41 PM | "Quote" | "Quick Reply" |

Joined: 01/30/2010
Location: nd

 


I have a 1982 50 hp Mercury outboard motor that over heats. When I’m in idol or going slow I get water going thru the motor but when I work my way up to speed the motor doesn’t pump water thru it to cool it. I changed the water pump this last fall and took it out for a test drive and it stills does the same thing. Not sure what to look for. Thanks for the help.
longball
Re: Boat motor over heats.
by on 12/19/2011 8:49 PM | Reply #1 | "Quote" | "Quick Reply" |

Joined: 02/28/2007
Location: ND
probably a blockage somewhere in the system. 
Re: Boat motor over heats.
by on 12/20/2011 07:37 AM | Reply #2 | "Quote" | "Quick Reply" |

Joined: 05/25/2004
Location: ND
Sounds like a water pump to me, 
Re: Boat motor over heats.
by on 12/20/2011 08:08 AM | Reply #3 | "Quote" | "Quick Reply" |

Joined: 08/12/2003
Location: ND
 Did you change the impeller or the water pump?
..............THIS SPACE FOR RENT..............
Re: Boat motor over heats.
by on 12/20/2011 09:49 AM | Reply #4 | "Quote" | "Quick Reply" |

Joined: 03/08/2011
Location: ND

Mercury's are known to suck up more sand thru their water intakes than most all other brands. Check your intake line and possibly inlet itself for any partial blockages, and as mentioned earlier, check the impellar. If sand got in there, the impellar might not have a snug fit anymore and you just can not supply the motor with enough water to keep it from over heating.

Some models of Merc's require you change the impellar every 100 hours of use.

Jack Dunn

I used to be indecisive, now I'm not so sure about that!
Re: Boat motor over heats.
by on 12/20/2011 9:26 PM | Reply #5 | "Quote" | "Quick Reply" |

Joined: 01/30/2010
Location: nd
I changed the impeller.
longball
Re: Boat motor over heats.
by on 12/20/2011 9:39 PM | Reply #6 | "Quote" | "Quick Reply" |

Joined: 08/12/2003
Location: ND
 
longball Said:
I changed the impeller.

Might think about a water pump swap-out then.
..............THIS SPACE FOR RENT..............
Re: Boat motor over heats.
by on 12/20/2011 9:51 PM | Reply #7 | "Quote" | "Quick Reply" |

Joined: 02/28/2007
Location: ND
isn't the impeller the water pump?
Re: Boat motor over heats.
by on 12/21/2011 09:03 AM | Reply #8 | "Quote" | "Quick Reply" |

Joined: 01/09/2002
Location: ND
The question I have for the owner is:

Does the motor lose circulation if you have it sitting still and just run it up to 3k rpm, or is this something that is only noticed when the boat is moving?  We don't know yet if it's an rpm problem or a water intake to the lower unit issue.  Are you sure you got the tube re-inserted correctly into the water pump outlet, or that it's not disconnected and bouncing around the base of the engine?  If I remember right, that tube has a rubber end and you may not have it properly placed in there, or the end could be damaged.  I had this on an old Mariner but the difference is it would pump water through the motor when revved up but not when idling.

Someone else mentioned a possilbe blockage in the system.  Have you tried to reverse the flow through the engine to flush it out?  My older Mariner had issues with sucking sand and leaves up that would plug the discharge on the side of the motor.  Probably shouldn't have, but I got tired of it happening and eventually reamed out the hole so it would pass small rocks.


eyexer, the impeller is the important part of the water pump, but the few boat motors that I have done the water pump replacement on had a kit you can buy of all the asundry gaskets and housing.  If a person is sucking up a lot of sand, the housing itself for the impeller may be damaged. 
“Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.” ~ Mark Twain
Re: Boat motor over heats.
by on 12/21/2011 09:54 AM | Reply #9 | "Quote" | "Quick Reply" |

Joined: 08/03/2005
Location: ND
Sounds like sand stuck in somewhere to me. When it tries to suck more water through, the sand acts as a plug.
Re: Boat motor over heats.
by on 12/21/2011 10:48 AM | Reply #10 | "Quote" | "Quick Reply" |

Joined: 10/30/2011
Location: Nd
The thermostat may be worth a check.  They don't fail often, but do fail.  I would think that if it's pumping water at idle, its lowest pressure, it shouldn't have a blockage that would stop water flow at higher pressure.  Possibly even the "key" that locks the shaft to the impeller could be missing or spinning.  At low idle it could be stiff enough to hold and upon reving could cause it to slip.  Just a guess without seeing it.
Re: Boat motor over heats.
by on 12/21/2011 10:54 AM | Reply #11 | "Quote" | "Quick Reply" |

Joined: 03/16/2010
Location: nd
are you getting a whistle from the motor telling you its hot? If so it could be not overheating had the same problem with a 60 merc. turns out it was a bad battery switch batteries and see if it still does it . sounds dumb but thats exactly what mine did and a new battery did the trick.
Re: Boat motor over heats.
by on 12/21/2011 12:31 PM | Reply #12 | "Quote" | "Quick Reply" |

Joined: 02/18/2004
Location: ND
Call Randy at Dakota sports in Dix at 225-0244, he is about the best boat mechanic in ND and might be able to answer this with a phone call.
 

If we're not supposed to eat animals, how come they're made out of meat?

Re: Boat motor over heats.
by on 12/21/2011 12:49 PM | Reply #13 | "Quote" | "Quick Reply" |

Joined: 02/28/2007
Location: ND
Allen Said:
The question I have for the owner is:

Does the motor lose circulation if you have it sitting still and just run it up to 3k rpm, or is this something that is only noticed when the boat is moving?  We don't know yet if it's an rpm problem or a water intake to the lower unit issue.  Are you sure you got the tube re-inserted correctly into the water pump outlet, or that it's not disconnected and bouncing around the base of the engine?  If I remember right, that tube has a rubber end and you may not have it properly placed in there, or the end could be damaged.  I had this on an old Mariner but the difference is it would pump water through the motor when revved up but not when idling.

Someone else mentioned a possilbe blockage in the system.  Have you tried to reverse the flow through the engine to flush it out?  My older Mariner had issues with sucking sand and leaves up that would plug the discharge on the side of the motor.  Probably shouldn't have, but I got tired of it happening and eventually reamed out the hole so it would pass small rocks.


eyexer, the impeller is the important part of the water pump, but the few boat motors that I have done the water pump replacement on had a kit you can buy of all the asundry gaskets and housing.  If a person is sucking up a lot of sand, the housing itself for the impeller may be damaged. 
I was being sarcastic lol

13 Replies | Page 1 of 11 | Top of Page | Bottom of Page
Posted By:
Posted On: 12/19/2011 8:41 PM
822 Views, 13 Comments

Tags: motor, over, heats, boat, water, thru, going, rsquo, pump, 0
More Tags: Hospitality_RecreationBusiness_Finance
Region: Global

Categories: Outdoor Sports > Boats
Rate This ForumTopic
  • Currently 5/5
  • 1
  • 2
  • 3
  • 4
  • 5

5/5 (1 votes cast)

You must be signed in to comment on this topic








Total Outdoor Network
TON Sites | Contact | Advertise | Privacy Policy | Terms of Use



North Dakota Fishing and Hunting | Minnesota Fishing and Hunting | Wisconsin Fishing and Hunting | Nebraska Fishing and Hunting | Walleye Fishing | South Dakota Fishing and Hunting | Alaska Fishing and Hunting |