1984 470 mercrusier Running hot

Reply

  #1  
Old 09-21-19, 05:36 PM
Member
Thread Starter
Join Date: Sep 2019
Posts: 1
Received 0 Votes on 0 Posts
1984 470 mercrusier Running hot

Have checked all fresh water pump , heat exchanger, check water flo through heat exchanger is good, still engine block and antifreeze resevour still getting hot. Hot enough to almost set engine cover on fire and burn up ignition coil. How do i check it antfreeze circulating. What else should I check.
 
Sponsored Links
  #2  
Old 09-22-19, 04:40 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 20,817
Received 198 Votes on 183 Posts
First are you sure the boat has fresh water cooling? Many of them had raw water cooling but they don't have heat exchangers.

Next I'd make sure the engine coolant pump is working. You can crack a hose loose and see if coolant sprays out when the engine is running. Or, you can pull the coolant pump and make sure the impeller is good. More commonly I have trouble with the raw water side. Make sure you are getting water flow through the entire system. Intakes or the raw water strainer get clogged, or the raw water impeller needs to be replaced.

Where was the boat used? Anywhere barnacles or zebra muscles are present? If so then I'd visually inspect the inside of the heat exchanger. Just because water is flowing through it doesn't mean the interior isn't covered in critters that are impeding the transfer of heat.

Also check the thermostat. For a quick check you can just remove it and see if the engine cools. For a better test you can hang the thermostat by a string in a pot of water while you heat it on the stove. Check the water temp with a thermometer and see if the thermostat is opening at the correct temperature or at all.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description: