Gasoline in a diesel engine

DannyS

.
May 27, 2004
933
Beneteau 393 Bayfield, Wi
Update... Yesterday I pumped the fuel tank empty. Today, I replaced all fuel filters and drained as much fuel out of any hoses I could. I pulled the fuel line off of the petcock to the pick up tube to the tank and put it into a gallon jug of fresh diesel. I pulled the fuel return line from the tank to the injectors and put that into an empty jug to capture any fuel returning to the tank. I then bled the system and crossed my fingers. She fired right up. I added 5 gallons to the tank, got everything hooked back up in the correct order and let her run for 45 minutes or so. Everything sounds good. Next step is to fill up the tank with fresh diesel and go sailing. I think I dodged a bullet on this one. I and the marina learned a valuable lesson.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,751
Hunter 430 Waveland, MS
when fueling with gasoline, marina personnel are supposed to request that all other passengers disembark while the fueling occurs. THAT is a very important action that I almost never see.
Since I verify my fuel tank level gauge, each time in fill up, I have to be below. My calibrated gauge will show, say 12 gallons to fill. I tell the filling person [the Admiral]..
1) give me 10 and stop.
2) wait for about 2 minutes for my gauge to stabilize.
3) ok, after verifying, give me 1 more.
4) Rinse and repeat till topped off.
5) I mark a spot on my calibration chart that verifies my gauge in working correctly, each time I refill.

My Wema fuel tank sender has been accurate [± 2 gallons in 50 tank] now for 3 years.
I consider it a safety device on my boat.:thumbup:
Jim...

PS: I still make a fuel consumption calculations that @Gunni taught me in SBO many years ago. TYVM!
 
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Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Since I verify my fuel tank level gauge, each time in fill up, I have to be below. My calibrated gauge will show, say 12 gallons to fill. I tell the filling person [the Admiral]..
1) give me 10 and stop.
2) wait for about 2 minutes for my gauge to stabilize.
3) ok, after verifying, give me 1 more.
4) Rinse and repeat till topped off.
5) I mark a spot on my calibration chart that verifies my gauge in working correctly, each time I refill.

My Wema fuel tank sender has been accurate [± 2 gallons in 50 tank] now for 3 years.
I consider it a safety device on my boat.:thumbup:
Jim...

PS: I still make a fuel consumption calculations that @Gunni taught me in SBO many years ago. TYVM!
That disembarkation requirement is for GASOLINE engines only.
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
That's interesting, I hadn't caught that before. In the marinas that I've been to that are part of the program, they've proactively done it 100% of the time. Not spilling is a developed skill. I suppose if a boater insisted, they would turn over the nozzle. Maybe why its worked like that.
The person doing the fueling is responsible for spills (and incorrect fueling) so I assume that most marina fuel docks do not want to assume the responsibility. They hand you the nozzle and witness for a potential spill. It can be mandated by law, as in New Jersey where fueling must be done by the facility operator.

There is advice in the Wisconsin guidance to only fuel to 90% which could equate to listening for the change in sound from the fill port - once the tank is filled the vent fills and air is expelled from the fill port in a different tone.
 
Oct 26, 2010
2,114
Hunter 40.5 Beaufort, SC
Something I don't understand here though. When I lived in Pennsylvania many years ago I routinely put about 2 gallons of gas in my 20 gal diesel Mercedes 300TD wagon to prevent gelling in the winter with no problems ever noted. I had 350000 miles on it and running great when A young girl hit it and it was totalled it. A little less mpg but no significant loss of power. This was even recommended by Mercedes. While its never a good idea to get something you don't expect and a higher concentration could be catastrophic I don't see 10 gas in a 50 gallon tank as a death sentence for the engine. Then again I don't ever think I read how much diesel he had to begin with. Maybe there's something special about how marine tanks breathe but it seems if you could get the concentration down to about 5% or so you'd be fine without drastic action.
 
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DannyS

.
May 27, 2004
933
Beneteau 393 Bayfield, Wi
I don't know enough about diesel engines to know if it will have any long term repercussions but I only had 5 or 6 gallons of diesel in the tank when 10 gallons of gasoline were added. It was a pretty high concentration of gas to diesel. The tank's capacity is only 30 gallons, not 50 as someone mentioned.
 
Oct 2, 2008
3,810
Pearson/ 530 Strafford, NH
Smokey hit on what I read about a year ago using some gasoline in diesel to clean injectors. I know the post was back a while. Anyways when I worked heavy construction we added kerosene in the winter to thin the diesel. Maybe our friends north of the line do this.
 
May 17, 2004
5,564
Beneteau Oceanis 37 Havre de Grace
Smokey hit on what I read about a year ago using some gasoline in diesel to clean injectors. I know the post was back a while. Anyways when I worked heavy construction we added kerosene in the winter to thin the diesel. Maybe our friends north of the line do this.
To quote @#1sleddog from the other thread about oil testing -
try to avoid “winter mix” diesel. It has more kerosene in it, so a lower lubricity. Still no big deal though.
 
Dec 28, 2015
1,897
Laser, Hunter H30 Cherubini Tacoma
Actually considerably MORE dangerous than gasoline. I've investigated accidents. Diesel fumes are non-flamable and gasoline fumes inside the tank are usually over rich, but this is likely to be "just right" to go boom. One truck exploded due to static because the wand used was plastic and did not conduct. The worker was thrown 30 feet. [The wand must be either aluminum or CPVC, and not PVC or PE.]

It needs to be pumped dry. Anything more than ~3% gasoline is flammable. It doesn't take much.
There needs to be some "redirecting" on this one...( your vapor explanation) . Diesel vapor is extremely flammable. Liquids do not burn, their vapors do. Diesel needs a lot of energy (normally heat) to generate vapor in quantities to be flammable. The flash point (temp needed to generate combustion) is around 140f for diesel (gasoline is around -50f). Once generated it only needs .6% volume vapor in atmosphere to combust (lower explosive limit). Alot lower than gasoline (1.4'ish). Jn the issue above the gasoline vapor would ignite which would in a compounding effect ignite the now produced diesel vapor. Same danger as gasoline, more btus after it ignites.

All flammable liquids around their flash point generate flammable vapor. If in a container, like a tank, they will be, more likely than not, above their LEL. Its the area around the tank you need to be cautious of. Change the environment and you are alot safer. Hope that helps.

"Pumped Dry" I think you are again referring to LEL. Dry is irrelevant. Remember, it's the vapors. You must displace the vapors to dream it safe. I've dealt with several people who have killed themselves by cutting on a "empty, dry" barrel. Not very applicable to the OP but it's a mind set. Hope that helps.