View Full Version : Diesel Fuel Question...

07-28-2001, 11:52 AM
Specifications for the Yanmar 1GM10 engine in Prairie Islander calls for diesel fuel with a cetane rating of 45. Would this be the same stuff they sell at truck stops in the US for trucks? Not that I'd have any other choice.

Gonna get that little hummer going in the next couple of days, John.


07-28-2001, 01:43 PM
Norm, perhaps the cetane rating of 45 corresponds to different grades of diesel, either #1 or #2 diesel fuel. Call up your nearest wholesale fuel distributor and ask them, perhaps they'll have a good answere for you.

[This message has been edited by RGM (edited 07-28-2001).]

07-30-2001, 03:31 PM
Well, to answer my own question: I went to the biggest truck stop in town, bought a fuel can (Boy was that dumb, $14 vs $7 at the hardware store for the same thing.) and asked the ass't fuel sales manager what the cetane rating of diesel was. She had no idea. "Your mean octane?" I should know to ask google first.

Cetane is rated on a scale of 0-100 with most diesel rating between 40 and 50 or so. The higher the cetane rating the easier the stuff fires, and indeed #2 diesel has a lower rating than #1. I paid a few cents more for premium but for all google knows premium is a meaningless term. In any case what I got will probably work.

Now the question is: How do I get all the air out of the lines. I installed a five gallon Vetus fuel tank--chincy piece of junk, surprisingly, which has the feed line out the top so I have to siphen fuel up and over into the filter. It is all down hill from there. Tomorrows challenge.


07-30-2001, 06:54 PM
Have plenty of bilge diapers, rags etc. on hand. Is your battery fully charged and ready for a work out? Double check to make sure your cooling and charging systems will be functioning. Fill your filter housing with fuel prior to lift off if you can. Some fuel filter housings are equipped with priming pumps. These are handy for drawing fuel from the tank into the filter housing. Your engine (fuel pump) has to get it from the filter housing to the injectors. Secure all the fuel line connection fittings, then while cranking the engine over go to each fuel line connector nut at the injectors and crack each fitting until fuel leaks/squirts out, then secure that fitting and go onto the next. This is where the rags come in handy. Keep your face and hands out of the line of fire from the diesel, there's a fair amount of pressure happening here. As you accomplish this for each injector your engine will be attempting to run. Don't get too alarmed by the white smoke and racket, it's just temporary until the air is out of the system. Repeat the loosening/bleeding/securing process for each injector until your engine purrs like a kitten. It's similar to bleeding brakes on a car, only noisier and smellier. You may get lucky and the little beast may bleed itself, unlikely though. This is best done with the appropriate sized tubing wrenches, or at least end wrenches. NO cresent wrench should be allowed anywhere near a fuel fitting. Have a back-up wrench handy, the first one is bound to fall into the bilge. Have good light and ventilation and just in case have a charged fire extinguisher close at hand. Good luck.

[This message has been edited by RGM (edited 07-30-2001).]

07-30-2001, 08:31 PM
Thanks RG. I was thinking (ya you betcha) the fuel pump was not self priming and I'd have to purge the air prior to spinning the engine. Your comments are just what I needed.



John R Smith
07-31-2001, 02:49 AM

the Yanmar GM10 should be dead easy to prime, if it is the same as mine. You do NOT need to spin the engine on the starter at all. The fuel pump has a priming lever on it. Pump away on the little lever and bleed at two bleed points - first one on top of the in-line bowl filter, second on top of the feed to the injector. Once you have solid fuel and no air at both of these, she should be ready to go.


Bruce Hooke
07-31-2001, 08:42 AM
I have to admit that I worked for a wholesale fuel distributor for a number of months and I never heard anyone talk about 'cetane ratings'! If you want to pursue it I would call your local Yanmar dealer and ask them what the heck their manual is talking about...

On the other hand, I think you're probably right in saying that the stuff from your local truck stop will work fine...