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E26-2. A few questions for the pros after a day of maintenance

acubria

Member II
I spent a day in the boat cleaning and doing a bit of maintenance. This is literally my second week trying to understand marine diesel motors ( or any motor) , so bear with me if my questions are too basic. BTW, my gear box keeps working great since I flushed it and added 250ml of SAE30 heavy duty oil.
My questions relate to the photos attached:
  1. When I start the motor after it has been sitting for days, a black oily and slimy looking matter comes out of the exhaust. See photo. Is this normal? Do I have to clean the exhaust elbow? any comments?
  2. I changed the motor anode today. See the old one ! In the 3rd photo you can see how dirty it is inside the anode's housing. Is this normal? I cleaned a bit around the opening but did not attempt to clean inside of it. Does my raw water system needs some kind of treatment? Vinegar flush??
  3. I changed the impeller. This photo shows the old impeller was installed with the arms pointing in the wrong direction..... (?). I installed the new one with the arms oriented the opposite way as per the Yanmar manual which makes sense as the impeller turns counterclockwise. Did I do this correctly?
  4. My fuel gauge either stays on zero, or if I tap it with my knuckle, it will jump erratically between what I think is the correct level and zero. It jumps around for a bit and then goes back to zero. Any ideas how to fix this? See photos 4 and 6 show the top of the fuel tank and the back of the fuel gauge.
  5. My stuffing box does not leak at all. I do see a faint hint of humidity in the gap between the stuffing box and the shaft. Is this enough?. I touched the stuffing box after about 30minutes of motoring and it was cool as a cucumber. Is 30m enough to test it? I am planning a 10 hour trip that may consist in a lot of motoring and I am a bit concern about it.
I am starting to enjoy this little Yanmar ! Next fuel filter and oil change.
Any comments will be really appreciated !
 

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goldenstate

Sustaining Member
Blogs Author
I spent a day in the boat cleaning and doing a bit of maintenance. This is literally my second week trying to understand marine diesel motors ( or any motor) , so bear with me if my questions are too basic. BTW, my gear box keeps working great since I flushed it and added 250ml of SAE30 heavy duty oil.
My questions relate to the photos attached:
  1. When I start the motor after it has been sitting for days, a black oily and slimy looking matter comes out of the exhaust. See photo. Is this normal? Do I have to clean the exhaust elbow? any comments?
Doesn't seem normal. Your theory that it is the exhaust elbow seems plausible. I've seen many references to replacing the stock units with stainless steel ones.
  1. I changed the motor anode today. See the old one ! In the 3rd photo you can see how dirty it is inside the anode's housing. Is this normal? I cleaned a bit around the opening but did not attempt to clean inside of it. Does my raw water system needs some kind of treatment? Vinegar flush??
There are products called RydLyme or Barnacle Buster if you want to push liquid through the cooling system to descale it. I have a fresh water-cooled motor so it is a little different. You can also disassemble it and clean it mechanically.
  1. I changed the impeller. This photo shows the old impeller was installed with the arms pointing in the wrong direction..... (?). I installed the new one with the arms oriented the opposite way as per the Yanmar manual which makes sense as the impeller turns counterclockwise. Did I do this correctly?
Looks correct to me.
  1. My fuel gauge either stays on zero, or if I tap it with my knuckle, it will jump erratically between what I think is the correct level and zero. It jumps around for a bit and then goes back to zero. Any ideas how to fix this? See photos 4 and 6 show the top of the fuel tank and the back of the fuel gauge.
Mine is just a bobber gauge that is integral to the tank. I would try to troubleshoot the part number if possible. Seems like a flakey electrical connection somewhere. Maybe clean the connection points?
  1. My stuffing box does not leak at all. I do see a faint hint of humidity in the gap between the stuffing box and the shaft. Is this enough?. I touched the stuffing box after about 30minutes of motoring and it was cool as a cucumber. Is 30m enough to test it? I am planning a 10 hour trip that may consist in a lot of motoring and I am a bit concern about it.
If the stuffing box hasn't heated up after 30 minutes, you're probably just fine.
I think the standard advice is to weep 1-2 drops when underway and none when the prop isn't moving.
I am starting to enjoy this little Yanmar ! Next fuel filter and oil change.
Yes! Clean oil and filter = happy motor.
Any comments will be really appreciated !
Good work! Keep going!
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hi
As no one has replied yet, I'll start on what I think is the easiest item, your fuel sender. I'm fairly certain it is not working properly because of the rust and corrosion at the tank connection, both the positive and negative wires. The risk is that they could break off as you try to disconnect them, so you may need a new sending unit. But if you can remove the wires, cut off the bad ends and crimp on shiny new connections, as well as brushing / sanding off all the rust there, my guess is it will work properly.
All of your pics show lots of corrosion, and that's never conducive to things working well.
I'm guessing that over time you'll need to work your way through the boat, cleaning up all the wiring connections, replacing hoses that have calcified, rusty hose clamps, etc.
I'm also thinking your heat exchanger, where you removed the engine pencil zinc, needs to be removed and taken to a radiator shop for major cleaning. Some do it themselves with muriatic acid, but I would spend the bit extra to get it done right.
Others will also comment, but this gets you started. :)
Frank
 

Alan Gomes

Sustaining Partner
(1) Regarding your first point concerning the black oily stuff: This is nothing to worry about. What you are seeing is a bit of unburned fuel on initial startup. I assume that after the engine fires and it has been rotating at speed for 10 seconds (or whatever) that this disappears. If it continued to put this out then yes, there would be a problem. But if it's just a bit on initial startup then no.

I could explain in detail why this is so, and while my dissertation about how the governor works on that engine would no doubt make scintillating reading, it would be a bit like telling someone how to build a clock when all they are asking is the time. But I'll give you the (believe it or not) abbreviated answer.

It has to do with how the governor works to control the position of the fuel rack. The fuel rack is a sliding valve that regulates how much fuel goes from the injector pump to the injector. When the engine is off, the rack is wide open, i.e., it wants to give the injector maximum fuel. Once the engine rotates, it applies a counteracting pressure (through some cunningly placed springs and some other fun hardware) that moves the rack to give less fuel. The throttle spring, on the other hand, applies pressure on the rack to open it and give the injector more fuel. More throttle, more spring pressure to open the rack, more fuel, engine runs faster. But the faster the engine rotates, you get more spring pressure to close the rack, less fuel, and slower engine speed. It's the balance or stasis between these opposing spring tensions that keeps the engine running at a particular RPM.

Anyway...so as not to get too far into the weeds....What can happen with the 1GM is that, for various reasons, the engine might not get up to speed quite quickly enough relative to the amount of fuel that the injector pump is puking into the injector on initial startup, and so fuel is being dumped into the cylinder faster than the little beast can burn it. (Remember: when the engine is off the rack is fully open by default.) That's why the belching stops once the engine gets up to rotational speed and the governer can get a handle on things with the correct spring pressure on the rack to furnish a correct amount of fuel for the engine's ability to burn it. The unburned fuel has to go somewhere, of course. And so it goes out the exhaust. What you are seeing on the water is that unburned fuel, mixed up with some carbon from your exhaust elbow.

Anyway....I've seen this happen on my engine more than a few times. You should experiment with the position in which you place the throttle before you start the engine. Try increasing the throttle a bit from where you are starting it now and see what that does. It might cause the engine to spin up faster and burn that bit of fuel that is now being dumped out the exhaust.

In any event, the short answer to your question is that it's not a worry unless the engine continues to belch out fuel after your run it for maybe 5 or 8 seconds or so.

Quickly on the other points:

(2) Good that you replaced the anode. Yours needed it. You can set up a flushing system with a valve so that you can draw fresh water from a bucket. There are products such as Salt Away that will break down the salt in the engine internals. Yes, you can use muriatic acid, but you need to be careful using that stuff so that you don't leave it too long in the engine before flushing it out. Maybe try the Salt Away first, which is harmless and will probably do what you want.

(3) I'm not 100% sure about this, but I think the impeller will correct itself once it starts up. I assume it pumped OK--right? Also, check the pump for leaks. The seals on that pump go bad easily, unfortunately.

(4) Can't help you on the fuel gauge because I have a mechanical gauge, not an electrical one.

(5) Your stuffing box adjustment sounds perfect to me.
 
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