Adding 2-stroke oil to fuel tank-good idea or bad?

[nightsky]

I was talking to a fellow boater the other day who suggested adding 2-stroke oil to the diesel fuel tank (ratio 100:1 diesel to oil) in order to add lubrication to the fuel for the fuel pump, which is missing with the low sulfur fuel available these days. He seemed knowledgeable on the subject, but I thought I would get opinions from here. What do you all think?

[tomschauer]

I am no diesel expert, but this doesn't sound like a good idea to me. Diesel, if I am not mistaken, has a higher viscosity and higher flash point than two stroke oil. I would think this would have the opposite of the desired effect, not to mention that good 2 stroke oil is $40.00 a gallon.

[mjk1040]

Google it, it's been tested and u can draw your own conclusion. I read 200:1 and marine 2 cycle oil was an improvement in a Cummins, but using other types of 2 cycle were not. There are other lubricants for diesel out there too. Mike

[waybomb]

I used to have an old Benz 5cyl diesel.
Even put about 6 gallons of gasoline in it one time by accident.
Ran real quite until the next fill up.
100s and 100s of thousands of miles on it. I mean many. Odo stopped at something like 450,000 or so.
Point is - you really don't need any additives.
And even putting gas in it couldn't kill it.

[Viper]

I know diesel has been loosing some lubricating properties over the years but IMO it still has enough lubricating properties all on it's own. Never had to fog a diesel for winter! Don't know anybody that has for this reason.

[nightsky]

Source of the post Google it, it's been tested and u can draw your own conclusion. I read 200:1 and marine 2 cycle oil was an improvement in a Cummins, but using other types of 2 cycle were not. There are other lubricants for diesel out there too. Mike

Thanks Mike. I did google it and came across a study of additives for ULSD to add lubrication. It seemed to be geared more towards diesel for automobiles. I am wondering if marine diesel is still LSD (in which case it probably still has enough lubricity to prevent early failure to fuel systems) or if it has aslo been formulated down to ultra low sulfur? If marine diesel is also ULSD then it seems that there is a case to be made for the the additives, although the 2 stroke oil didn't perform as well as some of the other additives. I've never given it much consideration before now in 35 yrs of operating diesel powered boats.

[mjk1040]

Marine Diesel is going to be ULSD, the same thing you get for automobiles, suppliers in this area don't carry anything else. Now if your located in a main commercial shipping area you may be able to get different types of Diesel. But I'm not sure you would want to burn that type of Diesel. I guess if what you have been doing and it's not broke, don't change a thing. Mike
PS-There is a EPA study out there if your interested.

[nightsky]

Thanks Mike. I will search out that EPA study too.

[PhilH]

Valvetec and other additive mfg have products to add to auto or marine diesels to improve lubricity. Thats all you can
do to protect older engines. That and frequent oil changes. NOTHING is more important to longevity than changing oil regularity as oil provides much of the lubrication and cooling on any diesel fueled engine. There is no way you can increase the sulfur content of diesel engines yourself, so go with an additive rather than add 2 stroke oil hoping it will turn a diesel into an outboard motor.