Old fuel

[dennismenace111]

Im in the process of purchasing a boat thats been sitting for about 1 1/2 years....to my knowledge the engine hasnt been run in that period of time...Not sure how much diesel is left in the tank....the engine is a 15 hp Yanmar...On the outside it looks pristine....turns over by hand....Im wondering if the fuel in the tank is so far gone that it will cause injector or pump problems if I try to start her up with it.

Any thoughts/ suggestions? If I drain the tank, what is the procedure to bleed the fuel system....Ive never owned a boat with a diesel before....

[Karletto]

to bleed the system you open a tube near/ on fuel filter or somewhere on the fuel system, turn the engine few times to press the air out, than close the system and start like normal. some people bleed it also on injectors

how old is the engine? modern engines have automatic bleeding; some engines you have to bleed by pumping a button, usually near/ on the fuel pump, and than start. a 30 year old engine can already have this button bleeding feature

it's no use to drain the tank couse old fuel is still in tubes. you have to disinstall all fuel system and drain it. if you ask me 1 1/2 years old fuel is not a problem at all. the biggest problem are sealants, belts etc

but it is great that it turns by hand

[EO32]

Originally Posted by dennismenace111

Im wondering if the fuel in the tank is so far gone that it will cause injector or pump problems if I try to start her up with it.

Have you tired to start it? My 2QM20 started on 4 year old fuel when I purchased my boat.

[dennismenace111]

I was afraid to try and start it before I cleaned the tank...Its a 1990 Yanmar 18 hp. motor...The motor itself is pristine...looks great and turns over by hand....Guess I was worried bout nothing...I ll clean the filters and give it a shot...Maybe I ll be lucky...wost that happens I suppose it that the injectors will get fouled.....

[Warren M.]

There was a similar thread to this on Sailboatowners.com recently. Most of the posters there stated you should just try to start the engine with the old fuel. I guess I'm swimming upstream by saying you should not try to run it (probably a Yanmar 2GM20F?) with the old fuel. While it may start and run on the old fuel, I think you are inviting problems all along the fuel system if you do so. I would open the tank by whatever means you can (on my boat I can unscrew the fuel guage atop the tank) and suck out all the old fuel. I would then add new fuel, replace the primary and secondary filters, bleed the system and then start her up. While it doesn't have anything to do with starting the engine, I also would change the oil and oil filter, too.

[btrayfors]

Dennis,

I agree with Warren...90+ %.

Diesels generally have three problems: fuel, fuel, and fuel.

Diesel fuel in the tank of your new boat may or may not be OK, depending on it's quality when purchased, additives used or not used, moisture levels, and what's come before (i.e., how dirty the tank has become over the years).

The safest approach is to dump the old fuel and CLEAN YOUR TANK. There are several ways to do this, either by direct access if there's an inspection plate easy to get to, or by using a professional filtering system which draws fuel from the bottom of the tank, filters it, and puts it back at pressure into the tank, with a wand used to clean the walls of the tank.

You really need to be neurotic, if not psychotic, about clean fuel if you want your diesel to perform reliably in all conditions. I can't tell you how many boats I've seen, know of personally, or have read about which have diesels that work just fine -- for years sometimes -- UNTIL they get into some rough water. The rough water shakes loose all the crap from the tank sides and bottom, it gets sucked into the filters, and....the engine stops!

So, to be on the safe side, do what you can to ensure that both the fuel and the tank are as clean as you can make them. And, of course, change the filters and the engine oil while you're at it!

Bill

[dennismenace111]

So....my fears were properly founded.....there is actually a company here in south florida that will do "DIESEL FUEL POLISHING" ...what ever that is...but I believe that they have a device that will suck the fuel out of your tank, filter it and pump it back in....they do it in such a way as to break loose any accumulation of YUK from the tanks and when they are done, you have clean fuel and clean tanks....but...I think they specialize in the big gold plater yachts here in Ft Lauderdale that carry hundreds if not thousands of gallons of fuel....my sail boat has a 15 gallon tank.

[btrayfors]

Dennis,

I had my 40-gallon tank done in Ft. Lauderdale years ago by such a company!

And, a couple of months ago, I built a portable fuel polishing unit for use by colleagues on boats along the Washington, DC waterfront. Too bad you're not here, or we could take care of you in a flash :-)

Bill

[Omatako]

This sure is a subject likely to generate differing opinions

Chucking out the old fuel and cleaning the tanks/lines/filters is clearly the safest solution.

It's also by far the most expensive.

If the filtration on your new boat is worth it's salt (excuse the pun) then the most economical solution is to run the engine for a while and check the water trap in the primary (assuming it has one).

If your filtration isn't worth it's salt, change it now.

If there is water or rubbish in the tank, it'll have settled to the bottom and given that the pick-up tube is generally very near to the bottom and you run the engine as is, it'll pick up the unsavouries first if there are any.

If there are, you're back where the other advice has you now (clean, chuck, polish, buy, spend, etc.).

If there aren't you'll save yourself a heap of money and agro and your engine will do just fine. There simply is no justification for throwing out fuel that's a year or two old unless it's obviously contaminated.

Just my opinion vs others

Andre

[Stillraining]

Oh shoot here I go again.... 2 cents more

You have a fuel polisher on your boat we all do.. its called your racor and secondary filter...not as big and eficent as a hired polishers equipment but the same principal...worst thing is you waste a couple filters..you will know in 20 min if you warrant having to go a different route due to whats being visible in your racor bowl...Good advice about the rough weather stiring up stuff..but same deal applies.. filters dont let contaminants past that easily..the stalled engines is usually due to the fact that the engine cant get fuel caus the filter isn't passing any due to water or gunk..90% of the time its water..
Hydrocarbon Utilizing Micro-organisms, commonly known as H.U.M. Bugs...a bug that lives in the water diesel interface and they are the ones most genrally the cause of the blackish gunk in diesel tanks. A bad case will require a tank cleaning..but your standard racor will handel most situations...basically no water in tanks no bugs...but we all know that aint going to happen due to condensation.

Its your engine you do what you think is best and makes you the most comfortable...Id fire her off and watch my bowl to see what gives...the fuel is not bad if thats what your woried about..its what is with the fuel thats always the culprit ....nothing with it nothing wrong with it.