Better Rinse

[Beachbummer]

So I had the opportunity to inspect my exhaust manifold after renewing them with used freshwater parts 3 years ago.

I boat in brackish water, and rinse after every outing

I can see already some damage the salt/use has caused.

As I examined the exhaust and it's routing my impression is that there is for enough water volume during rinse to fully wash all parts of the exhaust with fresh water.

It's the equivalent of showering with so little water not everything gets wet. No point in trying new soap, soap can't wash what is doesn't reach.

It seems to be, but I have not yet fully confirmed, that without enough back pressure the exhaust water forward fully our the back and bottom without pushing the water to the highest points of the exhaust water jacket on the head and manifold and specially opposite to the water nipples on the manifold. The channel with the hose nipples are good, and the channel's opposite that have no water nipples show signs of corrosion, specially at the higher points.

I wonder if pinching the exhaust exit hose at the last exhaust pipe might be an option to increase pressure... I'm open to any other ideas.

 

[FSH 210 Sport]

Simply put a clamp on the cooling water hose behind the WYE fitting where the flush water comes in like you wear getting a tow and you will cut off the flow of water out of the cooling water inlet from the jet pump which will dramatically increase the flushing water into the engine, of course you want to rinse that area as well, so just let it rinse fully out the back for a bit and put salt away through there, then shut off the water and motor, pinch off that cooling water line like you would if getting towed then start the rinse again and you will get way more flow out of the pilot circuit and into the rest of your engine. Follow the salt away instruction with basically say to rinse with fresh water until the thermostat opens then inject the salt away until you see the foaming at the exhaust exit and then shut off the water and engine and do not rinse out the salt away.

 

[Beachbummer]

I have a tow valve already. Does not do the trick. There's no exhaust pisser flow which means there is no pressure on the exhaust water outlet but instead it just trickles out the exhaust pipe and outlet.

 

[FSH 210 Sport]

That’s seriously low water flow at your house.

 

[Beachbummer]

At the marina. Maybe that's it.

Who gets an exhaust pisser during flush? I didn't see how the rinse is effective without the exhaust filling fully with water and the exhaust pisser showing water.

 

[FSH 210 Sport]

I get water out of the pilot outlet on the side of the boat, out the exhaust and out the jet pump. Until the thermostat opens then very little flow out the pilot outlet. If I’m doing an AIS decon thing I’ll clamp off the cooling water outlet after I get hot water of the pump then I get good flow out of the pilot water outlet.

 

[TeeNGee]

As far as I can tell, the water on the 1.8L engines, exits the exhaust manifold into the head and exits the head through the thermostat. Check out this thread for schematics. Scroll down to post #5 for screen shots. "C" is the pisser outlet. "D" is out the transom. "B" is from the pump

Thread 'Cooling water flow & hydro-locking'

Jun 18, 2025

Does the water highlighted in blue cool the exhaust manifold and enter the head without mixing with exhaust gases?
Is the red highlighted water flow the only water that mixes with the exhaust gases and subsequently cools the remainder of the exhaust (water lock, resonator, exhaust valve, & associated hoses) and out through the exhaust valve?
If this is the case, the water lock would need to fill to the level of the exhaust valves before water could cause a hydro-lock.
Am I interpreting these schematics correctly?

• TeeNGee
• Replies: 10
• Forum: General Discussion

 

[Neutron]

At the marina. Maybe that's it.

Who gets an exhaust pisser during flush? I didn't see how the rinse is effective without the exhaust filling fully with water and the exhaust pisser showing water.

I get water out the pissers without clamping the inlet line from the pump. But need the bow down lower than the stern

 

[qwikkotatx]

Mine has water flowing out of of both pissers but I am not sure when/if the thermostat is open. Are they similar to a car in that they open around 195°? One of my next projects will definitely be a dual temp gauge.

 

[Neutron]

Mine has water flowing out of of both pissers but I am not sure when/if the thermostat is open. Are they similar to a car in that they open around 195°? One of my next projects will definitely be a dual temp gauge.

Not sure the temp rating but i have seen older waverunners with 170 degree stamped thermostats

 

[Cobra Jet Steering LLC]

I know that I only run in salt water since I have used car wash soap with liquid wax in it to rinse my engines I have not had any issues with corrosion knock on wood and I have posted the process numerous times in the past decade or longer .

 

[Beachbummer]

Hey Jeff, @Cobra Jet Steering LLC so when you had MR-1 with the 2 pilot holes, did you get water out of both while rinsing? Thanks

 

[Cobra Jet Steering LLC]

Hey Jeff, @Cobra Jet Steering LLC so when you had MR-1 with the 2 pilot holes, did you get water out of both while rinsing? Thanks

never owned a mr1 only 1800 engines but the pisser is to tell you there is water going to the engine from the pump.. often the water pressure on a hose is not strong enough to create the water flow to the pissers due to some obstructions even mud dobbers have been known to get in the lines, but running it in the water the pump is a lot stronger. You can always check the mufflers and engines for any hot spots and comparison of the 2 engines to look for any issues when you are running it on the water using a non contact thermometer to check the head and manifold etc as soon as you shut it off , you can even check the water boxes to see if they are similar in temperature

 

[Beachbummer]

The MR-1 has a second pisser at the highest point of the exhaust rubber connector. It generally does not show any water unless there's some back pressure from the exhaust. When rinsing at idle I never see any water from this area, and I'm not sure how there's any good water pressure in that area if that pisser is not active.

 

[Cobra Jet Steering LLC]

Like I said I have never owned one of those nor ever heard of that .