Go Back  Offshoreonly.com > Technical > General Q & A
502 sucks water through air intake vents >

502 sucks water through air intake vents

Like Tree4Likes

502 sucks water through air intake vents

Old 09-04-2018, 07:43 PM
  #1  
Registered
Thread Starter
 
Join Date: Sep 2018
Posts: 14
Default 502 sucks water through air intake vents

1998 Formula, 25', with a 502. I always have water in the bilge.

The air intakes are below the sun pad, facing up at the back of the boat. They are at least a foot above the swim platform, and maybe two feet above the water line.

I've tested and found that water gets sucked in through the air intake vents when the boat is underway. It then just drains down into the bilge, but there is no specific path, so it drains under the batteries and onto the trim tab pump on its way. It's really a strange design.

Is my boat missing something? Is there supposed to be a baffle to prevent water from entering? If not, is there a way to modify it to keep water out of the bilge?
wmgreene is offline  
Old 09-04-2018, 08:31 PM
  #2  
Platinum Member
Platinum Member
 
Tinkerer's Avatar
 
Join Date: Jan 2002
Location: ALTO, MI
Posts: 4,607
Default

pictures would help us.
Tinkerer is offline  
Old 09-05-2018, 06:22 PM
  #3  
Registered
Thread Starter
 
Join Date: Sep 2018
Posts: 14
Default



Transom.


Opening under sun pad.


Opening under sun pad showing path to engine compartment.


Inside engine compartment looking up directly below opening under sun pad.
wmgreene is offline  
Old 09-05-2018, 08:37 PM
  #4  
Platinum Member
Platinum Member
 
Tinkerer's Avatar
 
Join Date: Jan 2002
Location: ALTO, MI
Posts: 4,607
Default

I would think that it is just exhaust water mist that is swirling behind the boat and then getting sucked into the engine compartment. The mist is then getting everything wet.
I don't think water is getting up there while you are on plane.
It sounds like you are going to have to find a better way for air to get to the engine.
Can you crack the engine hatch about an inch while on plane? I bet your water problem goes away if you do this. ( this is just for testing ) Install a permanent air intake that isn't from the back.
Tinkerer is offline  
Old 09-06-2018, 06:28 AM
  #5  
Registered
 
Join Date: Nov 2005
Location: Fredericksburg, Va
Posts: 4,555
Default

as a boat is pretty flat in the rear its the old station wagon effect water mist being sucked in, only cure it to seal the area with some sort of rubber flap etc, some boar worse than others with this..I have been on bigger cruisers and you actually get wet sitting in rear area
ezstriper is offline  
Old 09-06-2018, 07:32 AM
  #6  
Registered
Thread Starter
 
Join Date: Sep 2018
Posts: 14
Default

Thank you for your responses. I really appreciate it!
wmgreene is offline  
Old 09-06-2018, 08:34 AM
  #7  
Registered
 
Join Date: Aug 2012
Location: Collierville, TN and Pickwick Lake
Posts: 2,025
Default

Looks like someone has modified the engine hatch/sun pad at some point. I don't think that gap should be there. Don't you have vents on the side of the boat?
payuppsucker is offline  
Old 09-06-2018, 09:00 AM
  #8  
Registered
 
Knot 4 Me's Avatar
 
Join Date: Jun 2005
Location: Central IL, LOTO
Posts: 7,460
Default

The 252 did not have side vents and your air intakes from the rear of the sun pad look factory and unmodified to me. However, from your pictures I cannot tell if the engine compartment liner is still intact. Can you give a better pic showing the overall compartment and a pic of the entire underneath of the sun pad?

A few things stand out to me. One is your tailpipes or lack thereof. A second thing is the caulking around the transom plate. Might be another source of water in your bilge. A third is what appears to be a jigsaw cut in the transom wood on the starboard side.

These pics should help for reference:

https://www.powerboatlistings.com/view/48004

Rear sun pad area and air intakes:

https://www.powerboatlistings.com/view/38541
https://www.powerboatlistings.com/view/49203
payuppsucker likes this.

Last edited by Knot 4 Me; 09-06-2018 at 09:28 AM.
Knot 4 Me is offline  
Old 09-06-2018, 09:36 AM
  #9  
Registered
 
Join Date: Aug 2012
Location: Collierville, TN and Pickwick Lake
Posts: 2,025
Default

Yea I thought the same about the tailpipes.
Knot 4 Me likes this.
payuppsucker is offline  
Old 09-06-2018, 10:12 AM
  #10  
Registered
 
Join Date: Aug 2012
Location: Collierville, TN and Pickwick Lake
Posts: 2,025
Default



What is this cut?
Knot 4 Me likes this.
payuppsucker is offline  

OSO Sponsor
OSO Advertiser
OSO Advertiser

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

OSO Advertiser