Never use biocide with Yanmar?

[Ziggy]

While perusing my new Yanmar user's manual, I found an admonition to "NEVER add biocide" to the fuel (their caps). Does anyone here know why?

YES. The issue with boicide is that it kills all the algae in the tank, and leaves allot of dead algae in the fuel tank. This will promptly plug your filters.
Yanmar may have other reasons as well, but biocide in a boat is a recipe for problems.

[cat man do]

biocide in a boat is a recipe for problems.

What about if the tanks are new and have never had bugs in them?

Surely then, using biocide would prevent a future bug outbreak.

Dave

[GordMay]

"Fuel Guidance - Typical Shipboard Fuel Problems" ~ By Tom Gahs

“... There are four primary causes for these filter clogging problems: contaminates from your fuel source; chemical instability; microbiological contamination; and incompatibility between fuel loads ...

... A clue that the cause may be microbial is if the fuel/residue stinks (but this isn’t always true). Minor microbiological contamination problems can be successfully treated with biocides. However, a severe microbiological contamination problem, might require getting the fuel pumped off and having the tanks cleaned. Adding a biocide once a tank has become badly contaminated will generally cause growth adhering to the tank sides to slough off and drop to the bottom of the tank, or worse, into solution. Filter clogging may therefore worsen after you dose the tanks. Fortunately, a centrifugal purifier will generally be able to remove the microbiological contaminants ...”

Goto: http://www.uscg.mil/hq/elcbalt/docs/...elproblems.pdf

[Hud3]

I've used FPPF "Kill Em" biocide every time I've bought diesel since I purchased my boat in 2002. A Yanmar dealer in Virginia told me it was the only product approved by Yanmar. I believe my tank was clean to start, and has stayed thay way because of the biocide.

I agree that a "dirty" tank will slough off the bio-slime and clog filters endlessly. If your tank is that bad, you need to get it professionally cleaned. Not just filtered, but "air lanced" to physically dislodge the slime from the tank walls and baffles.

I became a believer in proactive tank hygiene after doing an offshore passage in a friend's 18 year old boat back in 2001. He had never used biocides. We experienced the inevitable gale during the passage, with "washing machine" waves. When the storm passed, we were becalmed, and couldn't get the engine to start. The filters were clogged from the dislodged bio-slime, and we didn't have enough spares to clean the whole tank. We ended up drifting dead in the water for 24 hours 400 nm north of the BVI until the wind finally returned.

[donradcliffe]

Why don't you ask Yanmar. I'm pretty sure that a lot of fuel distributors put biocide in the fuel before you ever get it.

[AnchorageGuy]

we have used biocides in our Yanmar since 2001 and have just past 1500 hours with no problem. You need to use the correct filters and change them.

[DeepFrz]

What about if the tanks are new and have never had bugs in them?

Then hopefully you have a fuel polishing system installed that will keep the fuel clean.

OK, so my response may have come across as bold, but I have had bad experiences with boicides. I agree that if the tank starts out clean, it should not be as much of a problem. I believe the bigger issue is how you maintain your fuel. Many boats with large fuel capacity, sit at the dock for long periods of time, allowing growth in the tank. I am a firm believer in multi tank systems. If a boat spends allot of time day sailing, why would you want to keep a hundred gallon tank filled. A simple solution is to instal a day tank. 5-15 gallons. Use this as your primary fuel source, then fill the bigger tank(s) if you are doing more extended cruising. This will eliminate the need for biocides, and other fuel additives. Even a boat that is used for extensive cruising will benefit from a multi tank system, as you may end up with bad fuel at some point, and the seperation will prevent the loss of all of your fuel. It will also provide a simple system to manage your fuel usage.
Eliminating the need to biocide, will eliminate any concerns over the results of it's use.

[Ziggy]

Thank you for all your replies, although my question is still unanswered.

Hud--with a brand new engine and a brand new fuel tank, I thought I'd also turn a new leaf with "proactive tank hygiene" until I read the owners manual. With my previous engine (Bukh DV20) I had no problems with tank growth, even though I never used biocide, until last summer when a disgusting glob of black goo plugged up the screen at the end of the pickup tube and the engine just stopped. Your experience with FPPF is encouraging, but I want to make sure I don't damage the engine or void the warranty. Also, all biocides I looked at had exactly the same list of active ingredients, so I would like to understand what the issue is.

Originally Posted by donradcliffe

Why don't you ask Yanmar. I'm pretty sure that a lot of fuel distributors put biocide in the fuel before you ever get it.

That's an excellent suggestion. I have contacted Yanmar and I will share their answer with this forum.

Originally Posted by DeepFrz

Then hopefully you have a fuel polishing system installed that will keep the fuel clean.

Fuel polishing system is a lovely idea, but not very practical in a 32' boat with barely enough room for a single Racor filter in the engine compartment.

Originally Posted by Kai Nui

If a boat spends allot of time day sailing, why would you want to keep a hundred gallon tank filled.

Well, my tank is 13 gallons, and it usually lasts half the summer. The bigger problem is lay-up in Winter, which allows several months for the critters to grow.

[Stranded Mariner]

Originally Posted by Kai Nui

OK, so my response may have come across as bold, but I have had bad experiences with boicides. I agree that if the tank starts out clean, it should not be as much of a problem. I believe the bigger issue is how you maintain your fuel. Many boats with large fuel capacity, sit at the dock for long periods of time, allowing growth in the tank. I am a firm believer in multi tank systems. If a boat spends allot of time day sailing, why would you want to keep a hundred gallon tank filled. A simple solution is to instal a day tank. 5-15 gallons. Use this as your primary fuel source, then fill the bigger tank(s) if you are doing more extended cruising. This will eliminate the need for biocides, and other fuel additives. Even a boat that is used for extensive cruising will benefit from a multi tank system, as you may end up with bad fuel at some point, and the seperation will prevent the loss of all of your fuel. It will also provide a simple system to manage your fuel usage.
Eliminating the need to biocide, will eliminate any concerns over the results of it's use.

That is good advice, and that's what I actually will have on my boat. One tank of about 100 liters, and one of about 400 liters.

[Roy M]

I can live without biocide! I have a fifty-five gallon diesel tank and a Yanmar 3GM30FW engine. The fuel is picked up one inch from the bottom of the tank and transported to a bank of of Racor filters VIA AN ALGAE-X UNIT. Yeah, I really wanted to stir things up here. Now the unending litany of "smoke and mirrors", "junk science", etc. is going to occupy this thread for a while. Unless, of course, one actually reads the Federal Technology report or the DTI reports on the Algae-X website (Algae X Fuel Conditioning). Hmmm, There appears to be some real science here, and hmmmmm, it seems to work for a whole lot of real-world users, and hmmmmmm, it sure is news to a lot of folks. Imagine, a "green" alternative to biocide, what a concept. Oh, and because the tank is small and accessible, I can drain the fuel, inspect the tank, and clean it when necessary.

In short, the beasties that create the muck in the fuel tank have iron in their guts. The unit aligns them magnetically, which allows them to pass through the filter medium, and pass through the injectors to be given a Viking funeral. Any crud generated by them is trapped by the filters, unless, it too is reoriented and capable of going through the filter. Whatever happens, there is less nasty stuff getting stuck in the filter. It doesn't relieve us of the necessity of occasional maintenance on our tanks. Not necessarily a bad thing, unless you can't get to yours.

[Ziggy]

I posed my question to Yanmar, and they forwarded it to their New England distributor (Mack Boring). I received the following reply from Bob Schroer,
Service and Parts Coordinator at Mack Boring:

"While Yanmar's position is that you should never add biocide or other additives to your fuel, this is not realistic in today's marine environment.

"There are situations, such as algae growth in the fuel, that do require the use of additives. Other situations would include low cetane fuel and the need to stabilize the fuel for storage.

"For years, we have distributed, recommended and used FPPF brand diesel fuel additives. (See attachment) Note the product "Killem" that is recommended for bacteria and fungi control in the fuel. The use of FPPF additives will have no effect on your Yanmar warranty."

(The attachment that Bob is referring to is the product info pages from http://www.fppf.com/completeproductlist.asp)

He did not explain the rationale behind Yanmar position against biocides. Note: Yanmar Owner's Manual does not have any statements for or against use of fuel stabilizers, cetane improvers, or other additives. Caveat emptor!

[Hud3]

As I said before, I've used FPPF "Kill Em" religiously for years, at every fill up. It keeps the crud under control, and the 4JH3 purrs like a kitten.

[CarlF]

Mack Borng probably knows more about Yanmar's than Yanmar. They basically brought Yanmar to the U.S. in the '70s. They also certainly know more about US diesel fuel formulations.

US fuel has been radically reformulated over the last few years for emissions standards with more to come. It doesn't store as well and has more trouble with water. Even if you could get by without additives in the past, you may need them now.

If Mack Boring says it doesn't void the warranty and goes so far to recommend additives, you can skip the "caveat" part. (of course, this still leaves about a million other "caveats" on your boat)

Carl