Engine Problem - help please

[Irish Rover]

My boat has twin Yanmar 4JH3-TE engines with over 3,000 hours Last week I noticed the port engine exhaust was very smokey at high revs - the smoke was white and afterwards, on reflection, I thought it might have been part steam. I took the boat out today for a spin today and just after leaving the berth the port engine shut down and wouldn't restart. It's was turning over but not starting. I went to a local anchorage and tried to start it again and it started but shutdown again after around 20 seconds. It was getting late and I didn't have much time but I opened the separator and bled off some fuel. It was a cloudy rusty kind of colour.
I've asked the marina mechanics to have a look tomorrow morning but I'm curious if any of you have any ideas of what it might be.

 

[oldgit]

Fuel contamination.
Filters blocked.
If tanks steel, water and rust ?
Do primary filters have glass inspection bowls. ?

 

[sogood]

Possibly water in the fuel, especially if it appears rusty and is creating white smoke/steam. Are both engines supplied by the same fuel tank? Wonder why just one engine is affected, unless it's a head gasket problem?

 

[Irish Rover]

Possibly water in the fuel, especially if it appears rusty and is creating white smoke/steam. Are both engines supplied by the same fuel tank? Wonder why just one engine is affected, unless it's a head gasket problem?

Separate tanks.

 

[QBhoy]

Has your coolant level dropped any ?

 

[Irish Rover]

Has your coolant level dropped any ?

Yes I noticed the expansion tank was low last week and it took close to 0.5L or a pint to bring it back to usual levels.

 

[QBhoy]

Yes I noticed the expansion tank was low last week and it took close to 0.5L or a pint to bring it back to usual levels.

Has it dropped again since perhaps ? Temperatures ok ? What’s the oil looking like ?

 

[Irish Rover]

It hasn't dropped again but I've not used it much since last week. Temp reading is normal and same as starboard. Oil on dipstick looked OK last week but didn't check today.

 

[vas]

oil filler cap, inside normal or yogurty? suspect blown gasket but not sure that's something that happens easily and out of the blue in such engines. What rpms are you usually running them?

 

[longjohnsilver]

oil filler cap, inside normal or yogurty? suspect blown gasket but not sure that's something that happens easily and out of the blue in such engines. What rpms are you usually running them?

Unless it’s hydraulicing I’d think it’s not the head gasket, it wouldn’t normally stop the engine. I’m in the contaminated fuel/partially blocked filters camp. Maybe along with a raw water constriction. Not unknown to have 2 simultaneous problems.

 

[Irish Rover]

My mechanic came this morning and checked. The inline filters were very dirty and he suspected water in the diesel. We got access to the tank under the bunk in the port cabin and there was a convenient inspection hatch. The diesel looked to have a strange colour and when he took a glass full it looked cloudy and dead. There's no sparkle and the colour looks like natural lemonade. He says it's water in the diesel and there's no bug. The tank looks clean otherwise and definitely no sign of rust. I checked my records and I filled both tanks on 03 August capacity 380lt each and they'reno showing quarter full.
His plan is to pump out the diesel 100lt approx, clean the lines and replace the filters.
I trust the mechanic's judgement but if anyone has other ideas I'd be glad to hear it.

 

[vas]

well, description fits symptoms.
Question is why on a cat with two tanks one got water one not.
I always suspect flush filler caps, how are yours? If they are flush mounted on deck, careful inspection of o-rings and what not in the route from filler cap to tank.
Assuming you filled at the same time, same marina, same hose, the only other thing is that diesel in the truck/whatever brought it to you had a bit of water at the bottom which ended up in one of your tanks only (bit far fetched...)

V.

 

[Irish Rover]

well, description fits symptoms.
Question is why on a cat with two tanks one got water one not.
I always suspect flush filler caps, how are yours? If they are flush mounted on deck, careful inspection of o-rings and what not in the route from filler cap to tank.
Assuming you filled at the same time, same marina, same hose, the only other thing is that diesel in the truck/whatever brought it to you had a bit of water at the bottom which ended up in one of your tanks only (bit far fetched...)

V.

Thanks for your opinion. I
haven't taken diesel outside my marina for nearly 3 years. Last fill was 03 August and both tanks took 320lt each. It may be significant I filled the stb tank first and the port is the one with the problem.
The filler caps are located on top of a narrow slanted bulkhead on the aft deck so I don't think it could have taken water there and the hose is not exposed anywhere.
Diesel now removed along with all filters. There was a brown sediment at the bottom of the tank which he cleaned as best he could through the inspection panel. The separator was almost mucky. There's an alarm on the separator and I'm curious why this did not activate.

 

[vas]

struggling to see how the marina layout would first pump the good diesel (which is at the top) and at the end the one with water... One way that could happen would be with a floating pick up pipe in the tank.
BTW was the tank build in the ground or a 2-5ton vehicle coming next to your boat?

I'd definitely have a look inside the filler cap and open both and compare condition of seals (if any)
hope someone else that gone through this can come with a better idea of how it happened.

V.

 

[Irish Rover]

İt's a fixed tank in the ground and the entire fuel station changed location about a month after my fill. I'll check both filler caps carefully, thanks.

 

[Irish Rover]

After the weekend lockdown I finally got my engine started yesterday. I refilled the tank and the mechanic bled off more fuel through the separator. When it wouldn't start he loosened off the injector heads and it spat out some contaminated fuel from there when I turned it over. After some more draining and bleeding if finally started. It chugged a bit at first but finally ran evenly. The mechanic poured some engine oil into the diesel tank which he said would help prevent damage to the pump and injectors - he cautioned however not to leave the engine idle for a long period as the pump or injectors could both develop rust after being contaminated by water. Fingers and toes crossed for now.

 

[vas]

got away v.lightly IR!

worth checking on the web if your particular engines have long term issues with contaminated diesel damaging injectors or high pressure pump and if there's any preventive maintenance you should perform right now (no idea!)

cheers

V.

 

[oldgit]

The mechanic poured some engine oil into the diesel tank

V. interesting ?

 

[longjohnsilver]

V. interesting ?

Yes, would be interesting to hear volvopauls thoughts on that. I wonder how much oil was mixed with the diesel.

 

[Irish Rover]

Yes, would be interesting to hear volvopauls thoughts on that. I wonder how much oil was mixed with the diesel.

Around 1.5L in 400L tank.