Unleaded Petrol put in Diesel Tank

[CeesH]

Don't worry, just be happy.. now you have those always missed few additional hp's

[daddle]

The alcohol in the gasoline might affect the seals. Gasoline itself, as said above, is not so different than diesel. Diesel is a mixture of wide variety of (cheap) hydrocarbons. Some of the lighter ones are essentially gasoline.

I would figure out the proportion of gasoline and call the technical representative of the engine manufacturer. Or just pump it out and then no worries. A small residue can't hurt much as the fuel companies are not too careful about keeping the fuel separate either.

[Wotname]

Originally Posted by hpeer

.........

So my synthesis of the well meaning advice is:

Pump out the top bit as soon as you can, using a gas rated pump or siphon. Try to get the light gas off the top. Measure it and if you can get a 10% concentration or less you are good. If not, waste the tank of diesel and start over.

Yes?

No, well almost Yes.
Don't waste the tank of fuel, pump out say 80%, keep aside, refill tank with diesel, use 10% then top up with the fuel put aside and so on

[mcarling]

Originally Posted by hpeer

I suspect that if you try to pump it out quickly then you may have some luck. But as the stuff sits and mixes that will become more difficlut.

I would expect it to be thoroughly mixed just about immediately as a result of the swirling around as it is pumped in.

Originally Posted by hpeer

What I also hears was that a 10% mix of gas into diesel is OK, kinda sorta. But more than that? At what point does it become too much?

It depends on the gasoline (higher octane is less bad here), intake air temp (colder is better), ambient air pressure (higher is better), and compression ratio of the engine (lower is better). However, none of these factors will make a big difference in practice. I would never run more than 10% gasoline / 90% diesel.

[mrm]

Originally Posted by mcarling

I would expect it to be thoroughly mixed just about immediately as a result of the swirling around as it is pumped in.

+1

It depends on the gasoline (higher octane is less bad here),

Actually, it is the other way around.

In Otto (gasoline) engines one wants the fuel to have low ability to self-ignite and the higher the octane number the lower the self-ignition ability of gasoline.

In Diesel (compression) engines high self-ignition ability is very desirable in fuel and is measured by cetane number.

Therefore, to 'winterize' diesel fuel one should use the cheapest, lowest octane gasoline available.

Additionally, if there is an exhaust catalyst involved, the gasoline used must be Lead-free. This is likely not much boat-related.

I would never run more than 10% gasoline / 90% diesel.

Volkswagen tech literature allows for maximum of 30% of gasoline, however with a remark, that at such concentrations difficulties in engine starting may be expected.


One more remark regarding possible gasoline/diesel mixture separation. Not possible with old style, hydrocarbon-only gasoline. Possible with modern, high alcohol content gasoline.

[mcarling]

Originally Posted by mrm

Actually, it is the other way around.

In Otto (gasoline) engines one wants the fuel to have low ability to self-ignite and the higher the octane number the lower the self-ignition ability of gasoline.

In Diesel (compression) engines high self-ignition ability is very desirable in fuel and is measured by cetane number.

Therefore, to 'winterize' diesel fuel one should use the cheapest, lowest octane gasoline available.

In diesel engines, self-ignition ability is desirable only up to a point, beyond which is bad. The risk from adding too much gasoline to a diesel mixture is the risk of going beyond that point. Having already added potentially too much gasoline to a diesel tank, higher octane gasoline is, as I wrote before, less bad.

If one starts out with the intent of winterizing diesel by adding a bit of gasoline, then low octane is desirable because slightly less is needed.

[Pearcey]

I think I am all for wasting the diesel just in case! - thanks for all the advice - just bought some new containers - (30 litres worth) and a siphon!

[Pearcey]

Any cleaning tips?

[DeepFrz]

Yes, clean your tank so it shines...

[MarkSF]

Originally Posted by Cotemar

+1, I do this every winter in my VW Jetta Diesel. One gal of gas per 15 gal full tank of diesel

I sincerely hope it's not one of the new generation of Jetta TDIs from 2009 on, as this practice is quite likely to destroy the high pressure fuel pump. VW have taken to testing the fuel on cars that suffer fuel pump failures, and if any gasoline is present in the diesel, they will not cover the repair - which costs $8000 to $10,000.

The problem is that the lubricity spec. of ultra low sulphur diesel in the US is only just high enough to lubricate the new generation of very high pressure fuel pumps, and ANY gasoline present reduces the lubricity below the acceptable level.

They also reduced the fuel pressure slightly on the the new Passat TDI, but Jettas are still particularly vulnerable.

[GaryMayo]

Originally Posted by gts1544

Pearcey, This might be a great opportunity to "CAREFULLY" clean out your fuel tank! Be sure that any electric pump that you use is "non-sparking" and approved for gasoline! We would hate to lose you! gts1544

In case you missed the advice above, read it again.

[GaryMayo]

Ask yourself these questions

How much do you like your sailboat?

Do you like it enough to have a marine diesel mechanic rectify the fuel problem for you?

Something that has not been mentioned yet, is fuel problems can mean rough starting, and backfires. A backfiring diesel engine can start running in the wrong direction, or backwards. When they do that, they run full throttle till they gerenade. Not pretty and dangerous for people near by. If it does start running backwards one of the only ways to stop it is stuff something in the exhaust which is now the intake, because it was running backwards. Because of the nature of marine diesels, if it started running backwards, it would most likely suck up coolant water if it uses a mixing elbow. Not good on an engine out of control, especially sea water.

I am sure someone will chime in with many reasons why my fears could never happen, and then you are left with my two questions.

[GaryMayo]

Originally Posted by MarkSF

I sincerely hope it's not one of the new generation of Jetta TDIs from 2009 on, as this practice is quite likely to destroy the high pressure fuel pump. VW have taken to testing the fuel on cars that suffer fuel pump failures, and if any gasoline is present in the diesel, they will not cover the repair - which costs $8000 to $10,000.

The problem is that the lubricity spec. of ultra low sulphur diesel in the US is only just high enough to lubricate the new generation of very high pressure fuel pumps, and ANY gasoline present reduces the lubricity below the acceptable level.

They also reduced the fuel pressure slightly on the the new Passat TDI, but Jettas are still particularly vulnerable.

New diesel fuel suc@s big time. If it ain't broke don't fix it. A century of trucks built the world, along with marine diesel applications. Then the gov got involved and made them change it. Interesting to see how smoothly the next century goes.

[Pearcey]

Got it! ....Every disaster so far has become a lesson to this rather "green" sailor...1 year on the learning curve continues to be steep yet weirdly satisfying...all women crew have I scared you now?

[kiwa]

Simple solution here Pearcy.

Find some wayward kiwi sailor whose on holiday and get him to help you with the tank.

Seeyatamora