Replacing 496 HO air purge fittings
05-17-2017, 07:19 PM
#1
Replacing 496 HO air purge fittings
Hey all,
I am buttoning up my new water pump project. When I was disassembling I saw that the purge air lines had some damaged fittings so I ordered new ones. Just because I don't want to wait on another part if I mess it up, can anyone tell me how to install a new air fitting? Does the end of the air line just press in?
Thanks!
I am buttoning up my new water pump project. When I was disassembling I saw that the purge air lines had some damaged fittings so I ordered new ones. Just because I don't want to wait on another part if I mess it up, can anyone tell me how to install a new air fitting? Does the end of the air line just press in?
Thanks!
06-01-2017, 07:04 PM
#3
Bought two new fittings.Looking on one side, whoever changed the water pump last looks like they pinched the line real well and I'm not convinced I'll get a good seal. There's not enough line to cut off the bad part without replacing the whole line. I'm not really in the mood to mess with this at the present.
Does anyone make a block off for these or know what fitting to buy? I'm guessing if I leave them open they will puke a little water out while running?
Does anyone make a block off for these or know what fitting to buy? I'm guessing if I leave them open they will puke a little water out while running?
06-02-2017, 08:20 AM
#5
VIP Member
If you just remove the air lines, it will not puke water.
The air lines pressurize an actuator/plunger that is spring loaded against the air. The spring is what keeps water in the motor. When you add air, that spring compresses, and water drains out. Remember, this system does NOT REPLACE THE WATER in the ENGINE WITH AIR. It only opens a port so it can drain. This is why it's so important to do a real/full winterization when it's time.
I used to carry a 6" long piece of pipe in my tool box that was the same OD as the barbs on the drain actuators. That way if you every have a failure of the spring (which does happen), you can remove the whole actuator; replace with the pipe, and carry on about your weekend.
Check your local Napa. They usually have tons of air line in the back, used for air line systems on farm and truck equipment.
FWIW: indicator of the spring starting to fail...
...if you have water in the bilge that you cannot explain; usually around 3000 RPM is when the water pressure going through the motor has enough positive pressure to overcome the spring. If you put the boat in the water, and can open the hatch a bit to see it running around 3000 RPM, you will see a stream of water coming out of the bottom of the air drain actuator. It's time to replace or rebuild it if so. I had this happen once, and it turned out to be a piece of wood that was jammed in the actuator holding it open. So just make sure you inspect your problem.
The air lines pressurize an actuator/plunger that is spring loaded against the air. The spring is what keeps water in the motor. When you add air, that spring compresses, and water drains out. Remember, this system does NOT REPLACE THE WATER in the ENGINE WITH AIR. It only opens a port so it can drain. This is why it's so important to do a real/full winterization when it's time.
I used to carry a 6" long piece of pipe in my tool box that was the same OD as the barbs on the drain actuators. That way if you every have a failure of the spring (which does happen), you can remove the whole actuator; replace with the pipe, and carry on about your weekend.
Check your local Napa. They usually have tons of air line in the back, used for air line systems on farm and truck equipment.
FWIW: indicator of the spring starting to fail...
...if you have water in the bilge that you cannot explain; usually around 3000 RPM is when the water pressure going through the motor has enough positive pressure to overcome the spring. If you put the boat in the water, and can open the hatch a bit to see it running around 3000 RPM, you will see a stream of water coming out of the bottom of the air drain actuator. It's time to replace or rebuild it if so. I had this happen once, and it turned out to be a piece of wood that was jammed in the actuator holding it open. So just make sure you inspect your problem.
Last edited by Sydwayz; 06-02-2017 at 08:25 AM.
06-02-2017, 05:05 PM
#6
That's excellent news. I never trusted the thing anyway so I don't feel bad at all about leaving the lines off then! Glad to know they won't leak. Thanks a bunch for the information guys. Maybe I'll save putting the lines back on for a nice winter project after I winterize it, just so she's 100%.
06-02-2017, 09:58 PM
#7
Registered
iTrader: (8)
If you just remove the air lines, it will not puke water.
The air lines pressurize an actuator/plunger that is spring loaded against the air. The spring is what keeps water in the motor. When you add air, that spring compresses, and water drains out. Remember, this system does NOT REPLACE THE WATER in the ENGINE WITH AIR. It only opens a port so it can drain. This is why it's so important to do a real/full winterization when it's time.
I used to carry a 6" long piece of pipe in my tool box that was the same OD as the barbs on the drain actuators. That way if you every have a failure of the spring (which does happen), you can remove the whole actuator; replace with the pipe, and carry on about your weekend.
Check your local Napa. They usually have tons of air line in the back, used for air line systems on farm and truck equipment.
FWIW: indicator of the spring starting to fail...
...if you have water in the bilge that you cannot explain; usually around 3000 RPM is when the water pressure going through the motor has enough positive pressure to overcome the spring. If you put the boat in the water, and can open the hatch a bit to see it running around 3000 RPM, you will see a stream of water coming out of the bottom of the air drain actuator. It's time to replace or rebuild it if so. I had this happen once, and it turned out to be a piece of wood that was jammed in the actuator holding it open. So just make sure you inspect your problem.
The air lines pressurize an actuator/plunger that is spring loaded against the air. The spring is what keeps water in the motor. When you add air, that spring compresses, and water drains out. Remember, this system does NOT REPLACE THE WATER in the ENGINE WITH AIR. It only opens a port so it can drain. This is why it's so important to do a real/full winterization when it's time.
I used to carry a 6" long piece of pipe in my tool box that was the same OD as the barbs on the drain actuators. That way if you every have a failure of the spring (which does happen), you can remove the whole actuator; replace with the pipe, and carry on about your weekend.
Check your local Napa. They usually have tons of air line in the back, used for air line systems on farm and truck equipment.
FWIW: indicator of the spring starting to fail...
...if you have water in the bilge that you cannot explain; usually around 3000 RPM is when the water pressure going through the motor has enough positive pressure to overcome the spring. If you put the boat in the water, and can open the hatch a bit to see it running around 3000 RPM, you will see a stream of water coming out of the bottom of the air drain actuator. It's time to replace or rebuild it if so. I had this happen once, and it turned out to be a piece of wood that was jammed in the actuator holding it open. So just make sure you inspect your problem.
06-04-2017, 12:24 PM
#8
Banned
iTrader: (9)
Sometimes the drains do not fully seat period - down the road, so they leak no matter what. . And sometimes WOT - higher water pressure the drains will leak water anyways.
If you look at the engine set ups without the air systems - you can set it that way taking the complete air system out of the MIX. I have done that many times on customers boats. And it looks totally stock professionally done.
I am not a fan of this drain system. 50 % of the time there is a problem with them or one lurking in short order.
If you look at the engine set ups without the air systems - you can set it that way taking the complete air system out of the MIX. I have done that many times on customers boats. And it looks totally stock professionally done.
I am not a fan of this drain system. 50 % of the time there is a problem with them or one lurking in short order.
Last edited by BUP; 06-04-2017 at 12:27 PM.
06-04-2017, 01:58 PM
#10
Banned
iTrader: (9)
I was talking about getting rid of all of it
MerCruiser 496 Mag (Base Model) Water Drain System Parts
MerCruiser 496 Mag (Base Model) Water Drain System Parts
