Go Back  Offshoreonly.com > Technical > General Q & A
496 troubles >

496 troubles

Notices

496 troubles

Old 10-06-2017, 09:57 AM
  #1  
Registered
Thread Starter
 
Join Date: Jul 2007
Location: BELLEVILLE IL
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Question 496 troubles

I have twin 496 hos , port motor exhaust on port side has very little water coming out. Triggering the manifold temp alarm, I have back flushed system even took riser off to inspect and flush? What I'am I missing or has anyone else had this issue?
I replaced both water pumps to the stainless steel Hardin model, but have put a few hours on with no issues before.
DOUBLE OR NOTHIN is offline  
Old 10-06-2017, 09:58 AM
  #2  
Forum Regulator
VIP Member
iTrader: (1)
 
Sydwayz's Avatar
 
Join Date: May 2001
Location: Worldwide
Posts: 23,218
Received 453 Likes on 203 Posts
Default

Have you cleaned out your Heat Exchanger?
Sydwayz is offline  
Old 10-06-2017, 10:04 AM
  #3  
Registered
Thread Starter
 
Join Date: Jul 2007
Location: BELLEVILLE IL
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

Yes I back flushed it, and replaced the gaskets. I have pulled off each hose to make sure water flow as well.
DOUBLE OR NOTHIN is offline  
Old 10-06-2017, 10:11 AM
  #4  
Gold Member
Gold Member
 
Dave M's Avatar
 
Join Date: Oct 2000
Location: Hollywood, MD, USA
Posts: 5,557
Received 51 Likes on 32 Posts
Default

Not that it should trigger an alarm but the port side usually does run warmer, particularly when running on the hose. Do you have a water pressure gauge?
Dave M is offline  
Old 10-06-2017, 10:15 AM
  #5  
Registered
Thread Starter
 
Join Date: Jul 2007
Location: BELLEVILLE IL
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

I have been backing down the ramp and starting it, I do have a water pressure gauge. That motor has been running lower psi so repalced the sensor and same result?
DOUBLE OR NOTHIN is offline  
Old 10-06-2017, 10:19 AM
  #6  
Forum Regulator
VIP Member
iTrader: (1)
 
Sydwayz's Avatar
 
Join Date: May 2001
Location: Worldwide
Posts: 23,218
Received 453 Likes on 203 Posts
Default

Have you checked your transom assembly hose for blockage or perhaps zerba mussel growth?
Some folks have seen collapse and corrosion in this area that has needed to be replaced/addressed.

Also, do you have a fresh water flush system? Sometimes there are parts in that system (the Tee into the sea water line) that get's gummed up with debris.
Sydwayz is offline  
Old 10-06-2017, 10:28 AM
  #7  
Registered
Thread Starter
 
Join Date: Jul 2007
Location: BELLEVILLE IL
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

Yes I checked that as well, Have anybody ever seen the exhaust drain fitting fail, I see there is a check ball in it??

DOUBLE OR NOTHIN is offline  
Old 10-06-2017, 10:37 AM
  #8  
Forum Regulator
VIP Member
iTrader: (1)
 
Sydwayz's Avatar
 
Join Date: May 2001
Location: Worldwide
Posts: 23,218
Received 453 Likes on 203 Posts
Default

Originally Posted by DOUBLE OR NOTHIN View Post
Yes I checked that as well, Have anybody ever seen the exhaust drain fitting fail, I see there is a check ball in it??

496 troubles-s-l500.jpg
I have not, but hopefully "BUP" will check in.

Question: How deep are you backing in the ramp when you evaluate? Are you going in just enough to get the pickups wet, or are you backing in deep enough that the water pump is in it's natural position with the SWP at or below the lake level? I'm just wondering if you have a suction/air-leak problem somehow.
Sydwayz is offline  
Old 10-06-2017, 11:06 AM
  #9  
BUP
Banned
iTrader: (9)
 
Join Date: Jul 2011
Location: Ft. Worth TX
Posts: 9,595
Likes: 0
Received 33 Likes on 28 Posts
Default

yes for the check valve or check ball however one calls them for owners. Easy testing here. take them out of the mix for testing only and use clear hose in place so you can watch for flow volume and air bubbles. one can go thru the cooling system per area with clear hoses to narrow down the problem by using clear hoses - they are used for testing only - as you replace the rubber cooling hoses is sections of the systems.

Back flushing sometimes is NOT the total way to clean out the cooling system. Have you check the oil cooler for restrictions meaning looked in there really well.

Are the end cap gaskets for the heat exchanger NEW ? Brand New ?

Exhaust manifold and rises internally in good shape with no restrictions ??? and all your gaskets and tabulator installed correctly ?

Condition of the cooling hoses - any collapsing or creased ? causing cooling water low volume output and restrictions ?

you can by pass the drive and the transom side for testing - big bucket of water next to the engine - buy an extra long hose to replace the inlet hose from the water impeller housing - stick your new long hose in that bucket of water and run the engine. check to see -- Did the output water flow volume increase ? You can test the water flow volume by collecting it out the exhaust to compare all your test results.

Last edited by BUP; 10-06-2017 at 11:09 AM.
BUP is offline  
The following users liked this post:
Sydwayz (10-06-2017), Todd B. (01-10-2021)
Old 10-06-2017, 11:17 AM
  #10  
BUP
Banned
iTrader: (9)
 
Join Date: Jul 2011
Location: Ft. Worth TX
Posts: 9,595
Likes: 0
Received 33 Likes on 28 Posts
Default

had to add --- do you have a dry engine compartment and bilge when you run the engine and shut it off ???? or do u get water collecting in the there even running the engine on the water hose ???

Watch out for the air actuator system and its drains as they can be a problem child for leaking water and or leaking air into the cooling system.
BUP is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.