Outboard cooling system - SailNet Community
 
LinkBack Thread Tools
post #1 of 7 Old 05-03-2006 Thread Starter
Junior Member
 
Join Date: May 2006
Location: northern va.
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Outboard cooling system

I have a 1995 Johnson 6hp sailmaster. Just installed new impeller. Trouble is the motor weeps fine until it gets warm then the flow stops. If I shut the motor off and restart it right away she weeps for a few minutes then the cycle repeats. Is this normal? Any help greatly appreciated. Thanks.
happyseidlemannowner is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 7 Old 05-03-2006
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 16,551
Thanks: 105
Thanked 316 Times in 302 Posts
Rep Power: 10
     
This is not normal, the "telltale" weep of the cooling flow is there to let you know that the pump is working. That flow should not be affected by the thermostat directly.
Assuming you are in Salt water:
Your tube to the telltale could be partially encrusted with salt, and as the water warms up expansion pinches off the flow (much as your bathroom taps "slow down" when hot water gets through). Also, perhaps with the thermostat closed initially there is enough pressure to push past the salt, and as the thermostat opens pressure to the weep drops and can't get past the blockage.
The loss of the weep telltale doesn't necessarily mean the impeller/pump is shot, but now you have no indication either way.

Remove the tube, ream/clean it out, clean out the port in the weep hole and check it again. It sounds like a fresh water flush wouldn't hurt either.
Faster is offline  
Quote Quick Reply Share with Facebook
post #3 of 7 Old 05-03-2006
Member
 
Join Date: Feb 2006
Location: St Louis, MO
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
DId you check the water inlet grills and the passage to the pump? They could be clogged with crud and closing off as it runs. Was the pump housing smooth where it meets the impeller? Why did you change out the old impeller? To repair this problem?
bmunse is offline  
Quote Quick Reply Share with Facebook
post #4 of 7 Old 05-04-2006 Thread Starter
Junior Member
 
Join Date: May 2006
Location: northern va.
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
yes i changed the impeller to repair this problem.housing looked o.k. i will follow some of "faster's" recomendations this afternoon, thanks everyone.
happyseidlemannowner is offline  
Quote Quick Reply Share with Facebook
post #5 of 7 Old 05-04-2006
Junior Member
 
Join Date: Dec 2004
Posts: 21
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
run the engine for a while in a mix of household radiator cleaner (for central heating systems) this will break down the scale and make the cooling system work again.
TalbotUK is offline  
Quote Quick Reply Share with Facebook
post #6 of 7 Old 05-04-2006
Senior Member
 
Join Date: Jun 2004
Location: Malaysia
Posts: 314
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
 
Take out and clean the thermostat and check it is not stuck open! Note that the thermostat is spring loaded. This works as a pressure valve. At high rpm the waterpressure from the pump push away the thermostat water by-pass and the engine emp should go DOWN! Put your hand on top of the engine, rev it up to above 200 rpm and check. If the temp does not drop about 10C you do not have enough waterpressure. In that case the problem may be a rubber grommet for the water tube where the water enters the cylinder block. In that case the block has to be lifted off the leg. There is even a possbility of exhaust leakage at port side of the engine due to defect gasket at the exhaust cover and a partly blocked cooling channel. If You are not afraid of a bit of work, by a power head gasket kit and change gaskets!
haffiman37 is offline  
Quote Quick Reply Share with Facebook
post #7 of 7 Old 05-04-2006 Thread Starter
Junior Member
 
Join Date: May 2006
Location: northern va.
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
o.k. this is what i did . filled 55 gal drum up to inlet port with h2o added lime and scale remover and ran engine. yes this worked, thanks everyone
happyseidlemannowner is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Outboard motor controls waltzingmatilda Gear & Maintenance 3 05-05-2010 09:08 AM
Waeco cold machine charging TahitiDave Gear & Maintenance 3 03-19-2006 07:52 AM
Deisel cooling system bidet Gear & Maintenance 4 05-14-2004 01:38 PM
Outboard Cooling windylake Learning to Sail 1 08-07-2003 11:03 AM
Salt Water Cooling System failure. rclampitt Gear & Maintenance 4 07-28-2002 09:26 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome