Which would be recmmended for a 1983 3 cyl 20 HP Yanmar Diesel? The Diesel Concetrate or the Diesel Modifier?

Which would be recmmended for a 1983 3 cyl 20 HP Yanmar Diesel? The Diesel Concetrate or the Diesel Modifier?

Greetings Squeak !
Amsoil diesel concentrate is the ticket.
Amsoil diesel concentrate replaces lost lubricity in ultra low sulfur diesel fuel, and is a total system cleaner which improves performance and fuel efficiency. You have the choice of 2 Amsoil diesel concentrates, DFC contains cold flow improver which lowers the cold filter plugging point by as much as 34 Deg. F.
ADF is for those who do not need a cold flow improver.
Here is a link if you wish to research further.
http://www.amsoil.com/a/fuel-additives-performance-improver?zo=531421

For those of you who deal with extreme cold take a look at Amsoil diesel recovery in the link above. Diesel recovery will save your bacon when you encounter extreme cold filter plugging due to wax. If the engine still runs, but will not accelerate, simply add diesel recovery to the tank and give it 10 to 15minutes to dissolve the wax then you are on your way.
If the engine is down because the fuel filter is plugged with wax, remove the filter and pour Diesel recovery directly into the filter, it will dissolve the wax and get the engine running, then treat the tank to prevent it from happening again.
Amsoil recently published an independent lab report in their action news magazine. The report tested B5 and B2 biodiesel fuel, and Ultra Low Sulfur Diesel treated with Amsoil Diesel recovery, the cold filter plug point was lowered to nearly 36 deg. F. below zero on each of the three fuels tested.
Amsoil diesel recovery does not contain alcohol, many of the diesel treatments on the market do. Alcohol is a drying agent that dries out seals and gaskets in the fuel system, it also affects lubricity of the diesel fuel which is already at an all time low.
If you live in a cold climate consider keeping a bottle of Amsoil diesel recovery handy as it will save you a huge headache in the extreme cold.
Have a great day !
Don

Hey welcome to the forum, waving a hand from Camano Island!

Thanks! Is the Diesel concentrate that was made in the 1990s O.K. to use? My neighbor gave me 3 qts. but I'm not sure if it is still good.

Thanks! Is the Diesel concentrate that was made in the 1990s O.K. to use? My neighbor gave me 3 qts. but I'm not sure if it is still good.

Wow Squeak, thats been around a while.
I don't believe I would use it if it's that old.
Don