Why does my diesel engine keep dying?

[Northbound44]

Originally Posted by jamhass

I would suspect (but have no real data) that an objection to the use of copper tubing would be it's tendency to work harden from repeated flexing or vibration.

Note that my Volvo uses copper coolant lines (both coolant and raw water) but these are all "firmly" secured to the engine, thus "theoretically" subject to less vibration.

Jamhass,

Following is an excerpt of an article from British Petroleum:

ACCELERATED AGEING
The ageing process can be accelerated by the following conditions:-
• Contact with zinc, copper or metal alloys containing them. These metals will quickly react with diesel fuel to form unstable compounds.
• The presence of water. Water allows the growth of fungus and bacteria, these produce natural by-products such as organic acids which make the fuel unstable.
• Exposure to high temperatures.
• Exposure to dust and dirt which contain trace elements that can destabilise the fuel,
such as copper and zinc.
• Fuel composition. Some components in diesel fuel naturally age quickly.

Link:https://www.bp.com/content/dam/bp-co...age-diesel.pdf

[Uncle Bob]

Originally Posted by undercutter

Especially if they run through bulkeads or turn sharp corners.

I concur, my boat has all copper lines from the fibreglass tanks to just beyond the racor filters, with rubber from there to the engine. All fittings are flared and lines have radiused bends, not fitted angles. Been this way since before I got it and has worked just fine to date. (touch wood )

Originally Posted by Northbound44

Briefly:
STORAGE LIFE
Under normal storage conditions diesel fuel can be expected to stay in a useable condition for:
• 12 months or longer at an ambient of 20oC.
• 6-12 months at an ambient temperature higher than 30oC.

ACCELERATED AGEING
The ageing process can be accelerated by the following conditions:-
• Contact with zinc, copper or metal alloys containing them. These metals will quickly react with diesel fuel to form unstable compounds.
• The presence of water. Water allows the growth of fungus and bacteria, these produce natural by-products such as organic acids which make the fuel unstable.
• Exposure to high temperatures.
• Exposure to dust and dirt which contain trace elements that can destabilise the fuel,
such as copper and zinc.

Northbound, you keep referencing this article but my experience differs, what do you recomend, follow advice probably achieved in a laboratory environment put forward by a large business with a vested interest, or follow the path of personal experience, both mine and many others with similar experience on similar boats?

[a64pilot]

You know your argument is the same as saying cigarettes don’t cause cancer, because I’ve smoked for years, and don’t have cancer, right?

[DeepFrz]

Because the line was partially plugged I suspect that the pickup tube is in the same condition. I recommend you pull the tube, clean and test it.

[Uncle Bob]

Originally Posted by a64pilot

You know your argument is the same as saying cigarettes don’t cause cancer, because I’ve smoked for years, and don’t have cancer, right?

I can see the similarity, but I stand by the suggestion that much can be achieved in ideal conditions for the position one is supporting, however similar weight should be given to real world experience.

I guess that you could compare the outlook of the large corporations involved, tobacco insisted their product didn't cause problems, and here we have petroleum saying don't store diesel fuel for more than a limited time and never in the company of copper or zinc. In both cases, buy more product.
Or perhaps I am just being cynical !!

[a64pilot]

Why don’t you look up what John Deere says.
When I was doing work to certify an aircraft to burn Bio Diesel we found that John Deere had done the most testing and written several scientific papers. We were already certified to burn Diesel fuel.
By the way only a fool would burn either Diesel or Bio Diesel in an aircraft turbine, but the owner of the company was told that he would sell more aircraft if it was.
Anyway John Deere found the same as far as what copper did to fuel, and I’d bet they are they ones that found it, and the fuel companies spread the word.

But warning someone of a situation that will shorten the storage life of your product does not sell more product, possibly not warning them of the situation could.

Just because Diesel ages which I believe is actually oxidized by the way doesn’t meant it won’t burn and burn well. What it means it that it will not burn as clean and will leave more residue and deposits, making your injectors dirty faster and of course polluting more and even possibly making an exhaust elbow more likely to clog.
Your choice to keep the copper or not, but the scientific data is in, the results are known, cigarettes do in fact increase the risk of cancer. Copper or zinc in contact with Diesel fuel does in fact cause it to age faster.

[sailingchiro]

Please check your shutoff valve. Both of mine were leaking.

[Northbound44]

Originally Posted by Uncle Bob

I concur, my boat has all copper lines from the fibreglass tanks to just beyond the racor filters, with rubber from there to the engine. All fittings are flared and lines have radiused bends, not fitted angles. Been this way since before I got it and has worked just fine to date. (touch wood )









Northbound, you keep referencing this article but my experience differs, what do you recomend, follow advice probably achieved in a laboratory environment put forward by a large business with a vested interest, or follow the path of personal experience, both mine and many others with similar experience on similar boats?

I wouldn’t argue about your experience but before retiring , I worked in industrial gas industry and did many field installations of gas related equipments ( nitrogen) and copper wasn’t allowed for piping and related equipments.
Based on this experience, I tried to use other materials like stainless steel, approved rubber hoses and Teflon for parts in contact with fuel or diesel.
I owned my previous boat for 15 years, put over 4000 hrs on engine traveling between east coast and Caribbean and never had issues with it.

[LifePart2]

SOLVED

Today we reached Bequia and I was able to buy some hose and fittings just before Piper Marine went home. They are all installed, and all seems to be working well! No more bubbles. It would have been a real bitch to try to run some new copper tubing in there, though.

The hose is well supported so I have no concerns about chafe. I still don't know where the leak was, but I am guessing the pipe was damaged when the tank was pulled out.

Anyway, thank you everyone for your suggestions! Now we can get back to cruising until the next repair ... well, actually, our jib started to tear during a 2 hour 35 knot squall today, so that is our sewing job for tomorrow. It never ends, does it?

Noel

[Gerrycooper56]

I had a similar problem but the engine was running fine until rough weather. Nothing in the tank like metal flakes or bacteria snot - it turned out that the rubber inspection hatch gasket was disintegrating and wisps of soggy rubber blocked the fuel pickup. The gasket had been cut to the tank top and not the lid so the gasket edges were exposed to diesel.

[MikeInMaine]

We had the same exact behavior. Turned out to be a tiny air leak where the downpipe in the tank was soldered to the fitting that secures it into the top of the tank.. Any fuel that leaked went back into the tank so it wasn't apparent. Replaced the pipe and problem went away. Was a pain to track down.

Mike in Maine
P-33-1 Brizo

[David Mathis]

A few years ago I had a similar problem. After several years of trouble free operation, the generator would stall a couple times a week then it got progressively worse until it would run for a few minutes under heavy load or maybe a half hour under light load then stall. The Racor 500 would be low on fuel so it would be refilled then the generator would start after a delay for self priming (Kohler 9CCOZ generator with a 3 cylinder Yanmar engine) and run OK for a few minutes again. Numerous bits of advice were offered such as, bad hose collapsing, loose connections, bad fuel shutoff solenoid, faulty shut off valve, and a few others. Numerous fixes were tried including changing the fuel hose. Finally, I removed the Racor filter monitor and installed the stock hold down bolt. That solved the problem. Now, I simply inspect the filter about once a week or maybe two on trips rather than rely on the indicator. Last year the filter was looking questionable mid trip (no-stalling yet) so it was changed and a month later the vacation was completed without any stalling. The Racor vacuum indicator seems like a good idea but didn't work as planned.

Racor vacuum gauges were installed on the dash for the main engines using the Racor 900s. They have been trouble free for many years and reliably show when a filter change is needed.

[Steve Whelan]

I'm no expert but sounds like a vacuum that is not letting the fuel flow freely. Just like an auto engine, the gas tank needs to breath. Did you try running it with the gas cap OFF to let the air flow?

[Xcntry]

Here is a list of problems I ran into cruising in the Caribbean:

- too many filters: a mechanic said Racor and engine final filter on my Westerbeke was enough. I had a third filter with the electric fuel pump. Noticed you had three.
- dirty filter: my engine idles rough and/or quits when I need to change the Racor filter.
- dirty fuel: may clog Racor quickly even after recent change of filter.
- micron rating of filter: check your manual for proper filter micron rating.
- debris in fuel tank: we suffered from our engine quiting unexpectedly for a couple of years after buying our boat. The previous owners had the problem. A mechanic in Grenada finally found latex strips in fuel that would cover the fuel intake in the tank.
- electric vs mechanical fuel pump: the previous owners switched to an electrical pump after fuel problems. A simple electrical pump that can be purchased at any auto parts store works great. They are cheap and can be quickly replaced when they fail.
- bad fuel: have your fuel polished if you sail in humid areas or where fuel contamination may occur.

I've never had an air leak problem on any boat...

[Ya Ubetcha]

Fittings designed for pressure may not work well when used in a vacuum situation. My Perkins 4-108 has different fittings on the vacuum side than on the pressure side. Just something to consider.