Wet exhaust not all that wet

[jetboy52]

In the continuing saga of getting my new to me Alberg 37 ready to go after sitting for 3 years, I started the Westerbeke 40. Since I am on the hard I had a plastic bin filled with water next to the engine with a hose from the water pump intake placed in the bin. After changing all filters, draining the old fuel from the tank and replacing it with fresh and bleeding the fuel system, it started up and ran like a top. The problem was that no water was being picked up out of the water bin. The water pump has a new impeller, and I took the cover off the pump and turned the engine over and the impeller was rotating. I was worried about overheating the engine (and the water temp gauge doesn't work) so I just ran it for a few minutes at a time. The coolant in the reservior never got so hot that I couldn't stick my finger in it. Just a few dribbles of water were coming out of the exhaust. I probably ran the engine for a total of 15 minutes and minimal, if any, water was sucked out of the bin. I tried to "prime" the water pump by holding the hose above the pump and pouring water down the hose but that didn't help. Does anyone have any ideas about what is going on here?

[Maine Sail]

Could be a number of things. Here are some thoughts that pop to mind.

1- Some boats have a seacock/valve on the exhaust outlet to prevent following seas. This may be closed.

2- Bad hose collapsing under suction. This happens sometimes with wire reinforced hose where the inner membrane breaks free and under suctions closes off.

3- Wrong impeller? Globe impeller with bad tolerances.

4-Air leak, strainer lid etc..

5- Worn pump body or cover not allowing a prime.

6- You made a tee into your intake but never closed the seacock??

[margitchris]

Are the vanes in the new impeller turned the right way?
Is the pick-up hose clear?
Have wasps made a home in your exhaust outlet that would block passage?
Does your exhause elbow need flushing?
Good luck!!

[Quetzalsailor]

Been there, but the boat was in the water at the time. Turned out to be a plant living at the throughhull. Took a while to troubleshoot my way back through the system.

Exhaust elbow is certainly a good suspect. But a pain to dissassemble. I'd take the impeller out and put the lid back on. Connect the raw water intake to a hose. Disconnect the hose to the exhaust elbow. Turn the hose on. If little water, check it out, piece by piece. Could be chips of rust inside the exhaust jacket or chunks of impeller. You could even back flush the jacket. Don't forget to put the impeller back in.

If there's lots of water passing, go on to the elbow (and to the hose supplying the raw water pump). Could be chips of rust lying in the exhaust or muffler. Could be chunks of a previous impeller.

I can't imagine wholesale plugging of the exhaust gasses; it would sound funny and the engine would not run for very long.

Despite the engine not being run for very long, and not yet warm, there'll be hot exhaust in the hose and muffler; don't burn it.

[jetboy52]

Thanks to you all for those excellent suggestions. I will start at the water pump and work my way back looking for a plug somewhere. I will let you know what I find.

[mitiempo]

If you connect a hose to the raw water intake be very careful with flow. It is generally a bad idea to run water into an engine under pressure - best to let the pump do the work.

[megalops]

Be really careful that the hot gasses from the exhaust didn't soften an exhaust hose somewhere. I did pretty much the same thing as you once and had this happen. 2 months later I had an exhuast leak, it has taken 3 years to get rid of all the soot in the engine room.

[Richincident]

I never did find out WHY my brand new impeller destructed, which led to a burnt exhaust hose and an exploded water muffler. However, once the smoke cleared and I started trying to figure out what do to next I got some very good advice and finally repaired all the problems--except that I had to replace the water muffler. Those little guys are pretty tough and once exploded resist all efforts to repair....

Now I lean over the transom about every five minutes, though the boat has been running VERY well for a month and a half. I suspect that in another year I will look over the transom on a less crazy basis.

Here's what I did to remedy the problem. I purchase a cheap bilge pump ($20) and used some spare hoses to run in into the cooling system from the top down--I attached the hose to the outlet that leads to the elbow. According to some great information on the web there is a phosphoric acid cleaner that is wonderful for cleaning out the passages of a diesel engine. Never found that stuff, but ordered some from a stoneworks supply house. Still waiting for the phone call on that one. Since I didn't have the "special" cleaner I bought 3 gallons of vinegar and poured them into a five gallon bucket with the bilge pump in it. I ran the outflow hose from the pump into the top of the MD-2, and put the input hose into the engine where the impeller was originally connected. Basically I circulated the vinegar in reverse through the cooling passages. I ran the pump and sat reading and watching the process for several hours. The next day I did it again with new vinegar. I also used a very skinny screwdriver into the elbow and tried to remove any grit there, in case there was a problem there. I had a great consultant on the phone whenever things went weird on me.

Better yet, here is the step by step information, which is now being copied from the Woodenboat Forum, where it was copied from a detroit diesel forum. I now have a very clean engine--but I did substitute vinegar because the only available cleaners that I could run out and purchase were muriatic acid based. I used the vinegar STRAIGHT, then dumped the resultant stuff in a hole in my backyard. Pretty dark by the end of day one....

I saved this from BoatDiesel forum...
Karl is about the most knowledgable fellow I know on Detroit Diesels...I tried this procedure on a hot tub spa heater and it works well.

Karl Denninger [ email ]
Date: 30 June, 2004 03:49 PM
Viewed: 417 times
Ok, I've been refining this process now for a couple of years, and am ready to share it with the forum...
This works for ANY heat exchanger that can be isolated - genset, engine primary, transmission, and your AC system!

You will need:

1. Inexpensive 500gph bilge pump with a 3/4" outlet. 20 feet of 16ga wire and a lighter plug (or suitable means to connect it to ship's 12V power)

2. About 15' of 3/4" hose.

3. A 5 gallon bucket.

4. 1 gallon of Ph-Ospho-RIC (from Home Depot, found in the paint department - about $13) This is phosphoric acid and a detergent.

5. Chemical resistant gloves and safety goggles are highly recommended.

To clean the H/E:

1. Close the seacock going to the H/E you intend to clean.

2. Remove the hose connections to the H/E. If it is a genset or A/C unit, there is a good chance the connection is 3/4" hose. If so, you're in like Flynn. Mains will have a larger hose inlet typically; 2" is popular.

3. If the inlet is up to 1", you can get nylon hose-barb adapters at most hardware stores to adapt 3/4" to up to 1". Buy the ones you need for your specific H/Es once. If the inlet is LARGER (e.g. 2") take one of the hoses to Home Depot or Lowes and come up with the PVC fittings to make up an adapter; 2" hose, for example, uses a 1-1/2" PVC coupler, a 1-1/2 to 3/4" threaded adapter, and a 3/4" hose barb to MIP nylon adapter. Fit up the pieces dry in the store and buy what you need. PVC fittings require PVC cement. Make up the fittings you need to adapt to the hose sizes in question.

4. Connect the output of the bilge pump to the OUTLET of the H/E using the adapter if necessary and half the 3/4" hose. Take the other half and connect it to the INLET, and run the hose back into the bucket. Place the bilge pump in the bucket. THE BUCKET MUST BE ABOVE THE H/E YOU ARE CLEANING TO INSURE THAT ALL AIR WILL BE EXPELLED.

5. IMPORTANT: Remove all zincs from their plugs, and reinstall the BARE PLUGS. DO NOT LEAVE THE ZINCS IN THE HEAT EXCHANGER!

5. Add roughly 2.5 gallons of clean water (half full). Turn on the pump and insure that the pump retains prime while circulating the water.

6. Add approximately 1/2 to 3/4 gallon of the Ph-Ospho-Ric to the bucket.

Allow the acid to circulate through the H/E until the foam and bubbling on the surface of the bucket's liquid STOPS. The amount of time this will require depends on how badly fouled the H/E is; it is not uncommon for this to take an hour or two. Phosphoric acid will "parkerize" steel and iron along with removing all the rust (a good thing!), and will ignore the cupero-nickel used in heat exchanger bundles. It will dissolve the organic, mineral and salt deposits, which is what you want. The solution will turn dark as it works. This is normal.

When the bubbling stops, turn off the pump. Drain the solution back into the source bucket.

Reconnect the original hoses and immediately start the engine or other device, allowing it to run, to flush any remaining residue out of the system.

Make sure to flush the hoses and pump with clean water when you're finished, and reinstall the zincs in the plugs.

You're done.

The solution can be reused several times. When done with it, you can use Baking Soda to neutralize the acid before disposal.

NOTE: Phosphoric acid contains phosphorus, and should NOT be dumped in the water as it is an algae nutrient, even after being neutralized with baking soda.

This procedure has several advantages over the other possibilities:

1. Its quick. I can do both mains, the genset, and the AC system in a day, and during most of that I can be doing other things as its all pump work time. Dismounting H/Es or disassembling bundles is quite a bit more work and in many cases requires draining the freshwater side of the system.

2. It is a LOT safer than the DD-recommended Muriatic/Oxalic acid solution. Muriatic acid is a MAJOR hazard if it spills - especially on you. Phosphoric acid is much less dangerous to handle. In addition, Muriatic acid causes hydrogen embrittlement of metals over time, which Phosphoric acid (mostly) avoids. If you leave the Detroit solution in too long, it will do damage. This is much less likely with the Ph-Oshop-Ric.

3. It works just as well as the DD recommended solution, if not better. You can confirm this with a flashlight - and your temperature gauge - after doing the deed.

Once you've made up the adapters, this is a very quick and easy maintenance procedure to do annually, which will keep you from having overheating problems during the season.

[Skipper Dan]

You can also find this in the Dairy section of most farm stores it is called "Milk Stone remover". Or "Acid Wash". I use it for cleaning aluminum plane parts.

Dan

[Richincident]

NICE! There are no farm stores near here but it is a good thing to find another potential resource. I will use the stuff in the off season to give her a scrub, but it is good to know that I can look in other places for it. Home Depot has only muriatic acid based cleaners now, so I have been looking for other sources.

THANKS,

[jetboy52]

Thanks to all for the great information on this topic. I ended up backflushing my system from the exahust elbow forward and things looked pretty clean. Then I tested the output of my water pump and it was nil, even with a new impellor. I replaced the water pump and the problem was solved. I went sailing for about a month but now I am removing the high pressure fuel pump to fix a small diesel leak which is discussed in a separate thread in this forum.