No Exhaust Water

[Contraman]

I'm new to sailing and have a 1980 Pearson 30 with a Universal 5411 engine with a raw water cooling system. I made a very rookie mistake and forgot to open my raw water through hull when motoring out to sail. I noticed a rubber burning smell on the return to mooring which turned out to the impeller. None of the blades broke off and I replaced it the next day but no water came out the exhaust when I started up.

I took off the hose from the impeller pump to the engine and filled it with water to prime it. Still nothing. I tried blowing on this hose to force water through the block but was unable to force any water through the system. With this hose disconnected, there was water coming from the impeller housing but rather weak stream....more like a very old man taking a leak.

I talked to someone at the marina who mentioned something about the exhaust hose collasping from the heat but didn't understand.

Help!

[savoir]

Replace both of your salt water pipes. There are only two - one in and one out. While you are there open up and clean the strainer. That is a round filter that will be part of the salt water inlet system.

[Contraman]

Originally Posted by savoir

Replace both of your salt water pipes. There are only two - one in and one out. While you are there open up and clean the strainer. That is a round filter that will be part of the salt water inlet system.

I cleaned the strainer and will replace both intake and outtake hoses on the impeller when I go to the boat today. Two questions:

1. With the out hose disconnected from the impeller, what kind of flow should you be getting from the impeller. Should it shoot out- an inch or so? Mine dribbled out? Steady dribble but not very impressive.

2. Should you be able to blow on the out hose from the impeller and force water through the engine block(yes, this is a raw water cooling system on the 5411)? I was unable to do so even with the engine running and gave up when I could feel some heat on my lips!

Since my problem started with the burned up impeller it seems unlikely that the problem is on the intake side, right?

[savoir]

Not unlikely, just less likely. Put a hose into the inlet pipe and turn on the water to check whether it is clear.

The salt water doesn't go through your engine block only into the heat exchanger. There it picks up heat from the fresh water in the engine.

Also the heat may have warped your salt water pump and it might be sucking air so a new pump might be in order. First be sure that the joins at the hose clamps are clean. There might be a crack in one of the hoses or the rubber might have perished. New pipe will be a help with that. Also have you replaced whatever O rings or gaskets are in the pump assembly ? The heat might have perished them and then that becomes another place air might get sucked in.

[sabray]

Check from the exhaust elbow all the way to the discharge point. Check the water lift. You probably did not smell the impeller but hot exhaust burning a hose or trashing a water lift. Back
Plate on the pump may have been ruined too.

[Sailmonkey]

Originally Posted by savoir

Not unlikely, just less likely. Put a hose into the inlet pipe and turn on the water to check whether it is clear.

The salt water doesn't go through your engine block only into the heat exchanger. There it picks up heat from the fresh water in the engine.

Actually the salt water goes into the engine. There is a bypass T that can be crusted up. The best bet here is to trace out the lines and check each section.

[Dsanduril]

Originally Posted by Contraman

1. With the out hose disconnected from the impeller, what kind of flow should you be getting from the impeller. Should it shoot out- an inch or so? Mine dribbled out? Steady dribble but not very impressive.

Depends on where the end of the hose is held. If you are very close the level of the boat's waterline then flow will be very little. However, if the end of the hose is below the waterline by more than 6 inches (15 cm) or so you should get a full-hose flow. If you're not, and you've cleaned the strainer etc., then could be fouling of the intake under the boat. Intakes are hard to anti-foul and typically get a lot more growth than the rest of your bottom.

If you suspect the intake, you can try a garden hose connected to it and try to push water (and growth/garbage) out the other direction but if it is hard growth (barnacles, etc.) then the only option is to chip them out. On our boat from inside with the seacock wide open you can slide a round dowel (just a little smaller than the pipe diameter) down through the seacock to dislodge things. If you wrap a rag around things as you work you don't get too much water in the boat. This will only work if the seacock is full-port (i.e. has an opening the same diameter as the pipe) and if you aren't timid. Last thing you want is to end up with a seacock you can't close. The other option is to jump in with a mask and snorkel (or haul the boat) and work from the outside.

If you do clean the intake, make sure you run plenty of water through it and the hose into a bucket so you clear any debris before running it into your engine.

2. Should you be able to blow on the out hose from the impeller and force water through the engine block(yes, this is a raw water cooling system on the 5411)? I was unable to do so even with the engine running and gave up when I could feel some heat on my lips!

Don't know your exact engine, so grain of salt, but all raw water cooled engines I am familiar with have a bypass for water flow. Since the water is intended to also cool the exhaust, and since the pumps are positive displacement, they have a bypass to move the water to the exhaust when the thermostat is not calling for cooling in the block. In that case you should be able to pass water regardless of engine state/temperature. Be careful in all of this testing, the last thing you want to do is fill up your exhaust system with water and have it flow backward into the engine, through the open exhaust valve(s) and into the cylinders.

[Algol]

This may sonud stupid but check your salt water intake valve,check is the water going trough when you move the lever.

[Stumpkiller]

Have you snaked the intake line to the impeller? A plastic bag, seaweed, jellyfish, etc. could be plugging the line between through-hull and strainer basket. I found a whole dead fish in mine once.

And if you drained your water-lift muffler last fall did you replace the drain-plug?

And did you check the heat-exchanger for crap? Even if you found the vanes something might have dislodged in all the poking and dosassembling you have been doing. It's easy to plug the little open ends of the exchanger tubes.

[Sailmonkey]

Originally Posted by Stumpkiller

And did you check the heat-exchanger for crap? Even if you found the vanes something might have dislodged in all the poking and dosassembling you have been doing. It's easy to plug the little open ends of the exchanger tubes.

No heat exchanger on a 5411. I'm still betting the bypass has fouled up.

[savoir]

Originally Posted by Algol

This may sonud stupid but check your salt water intake valve,check is the water going trough when you move the lever.

Not stupid at all. It's a popular hangout for barnacles.

[John A]

Originally Posted by Contraman

1. With the out hose disconnected from the impeller, what kind of flow should you be getting from the impeller. Should it shoot out- an inch or so? Mine dribbled out? Steady dribble but not very impressive.


Since my problem started with the burned up impeller it seems unlikely that the problem is on the intake side, right?

This is a good place to start. I'd suggest that you get the impeller pump rebuilt. The bearing can fail, the cover plate can be damaged, or the blades can self destruct.
A buddy boat I was with sucked a jellyfish into his.

[Contraman]

Originally Posted by Sailmonkey

No heat exchanger on a 5411. I'm still betting the bypass has fouled up.

I'm on the boats thanks to my iPad. Opened through hull without hose. Steady water entered not the gusher I was expecting in fear. Seacock has 90 degree angle so can't stick anything in there. I also went under the boat and ran a putty knife between the slots in the guard and felt nothing unusual.

If the by pass T is the T shaped coupling that brings the return engine water back before thermos opens up as well as new water, I opened this up and it is clear.

I noticed a steady drip of water from a small hole in the shaft of my water pump impeller but no evidence of water in the oil. Are there two seals on the impeller shaft with the first one leaking?

Hope this is helpful. Thanks.

[Sailmonkey]

There are two seals in the pump. But you also stated you couldn't blow through the water system.
Have you checked to see if the mixing elbow is clogged? Or have you run the engine with the water hose off of the mixing elbow to see if water is getting there?

[Contraman]

Originally Posted by Sailmonkey

There are two seals in the pump. But you also stated you couldn't blow through the water system.
Have you checked to see if the mixing elbow is clogged? Or have you run the engine with the water hose off of the mixing elbow to see if water is getting there?

I'm not sure what the mixing elbow is. I have a 5411 engine manual in front of me. In the sea water circulation diagram there's the "engine to manifold hose" and a "water to exhaust line and muffler" hose from the thermostat. Is either of these what you are talking about?

Thanks.