Major problem? No, just bad fuel

[California]

Bad fuel recently gave me a nightmare of bad performance. This Yanmar YM186D is from early 1980's so after 45 years anything seems possible. But today I put in fresh diesel and to my relief, this solved the problem. It purrs again.

Last weekend I mowed, and spent some time grading the lane. Performance deteriorated from just rough idle, to frequent ran-out-of-fuel rpm drops or individual cylinders misfiring. I feared the worst. Something fouled the injectors? Governor is sticking? That's what it felt like. Full throttle under load did not make exhaust smoke as the rpms dropped.

Today I suctioned the fuel tank empty. Blew out the fuel line from the pump back to the fuel filter location with the the filter removed. Then went to the expensive Chevron station for fresh name-brand fuel. Used some of this to flush from the tank to the fuel filter location.

Put in a new fuel filter and refueled with the fresh diesel. Then bled the system as Yanmar recommends - filter inlet, filter outlet, then at the injection pump. The engine started instantly. Now it idles smoothly down to 600 rpm like it should, in contrast to recently where below 1300 rpm risked killing the engine. I did some more mowing under heavy load and it just purrs.

Lesson learned: I've always bought the cheapest gasoline and diesel. Never had a problem before. But the local Rotten Robbie brand red diesel I'm using up from a purchase last year, doesn't make the Yanmar happy.

I use Power Service gray bottle fuel additive. Anybody have a suggestion how to make my 15 gallons of crummy diesel on hand, usable?

 

[ponytug]

Yeah, gunky fuel did a number on a car of mine many moons ago. Chevron or Shell for me ever since.

I've got a fuel tank to clean of some sludge that I think came from a lubricity additive that I used in the fuel for some older engines that had biodiesel in it that I think turned to a gum. What a mess.

All the best,

Peter

 

[dodge man]

If the fuel is bad I don’t think any additive is going to make it good again.

 

[5030]

I use Power Service gray bottle fuel additive. Anybody have a suggestion how to make my 15 gallons of crummy diesel on hand, usable?

Try filtering it through a Mr. Funnel.

 

[KennyG]

I use Power Service gray bottle fuel additive. Anybody have a suggestion how to make my 15 gallons of crummy diesel on hand, usable?

Use it to clean greasy parts and to start brush fires.

 

[5030]

Use it to clean greasy parts and to start brush fires.

He's in Kalifornia so using old diesel as an accelerant would get him a vacation in the barred hotel.

 

[2515R Dude]

He's in Kalifornia so using old diesel as an accelerant would get him a vacation in the barred hotel.

He doesn't have to report it to authorities

 

[Katahdin]

Just dewater and filter it, then mix it in with the fresh diesel a gallon at a time.

 

[careyo63]

I have Off Rd. Diesel and Reg. pump. close to the house. No Taxes. High Fuel, prices would be the only reason for me to use it. The reason I don't use off Rd. is you I can't see the fuel filter or in the fuel bowl hardly for that matter. Had it out yesterday and looked in it! Super clean and it's been Hundreds of Tach hrs. since I changed it! Napa auto for the filter replacement.

 

[bmaverick]

Bad fuel recently gave me a nightmare of bad performance. This Yanmar YM186D is from early 1980's so after 45 years anything seems possible. But today I put in fresh diesel and to my relief, this solved the problem. It purrs again.

Last weekend I mowed, and spent some time grading the lane. Performance deteriorated from just rough idle, to frequent ran-out-of-fuel rpm drops or individual cylinders misfiring. I feared the worst. Something fouled the injectors? Governor is sticking? That's what it felt like. Full throttle under load did not make exhaust smoke as the rpms dropped.

Today I suctioned the fuel tank empty. Blew out the fuel line from the pump back to the fuel filter location with the the filter removed. Then went to the expensive Chevron station for fresh name-brand fuel. Used some of this to flush from the tank to the fuel filter location.

Put in a new fuel filter and refueled with the fresh diesel. Then bled the system as Yanmar recommends - filter inlet, filter outlet, then at the injection pump. The engine started instantly. Now it idles smoothly down to 600 rpm like it should, in contrast to recently where below 1300 rpm risked killing the engine. I did some more mowing under heavy load and it just purrs.

Lesson learned: I've always bought the cheapest gasoline and diesel. Never had a problem before. But the local Rotten Robbie brand red diesel I'm using up from a purchase last year, doesn't make the Yanmar happy.

I use Power Service gray bottle fuel additive. Anybody have a suggestion how to make my 15 gallons of crummy diesel on hand, usable?

Ah ha, you experienced what I found out back in 2014. I too learned NOT to visit the nearest off the beaten path mom+pop station to get off road diesel. After a few fill ups and running the tractor, I noticed hesitation, misfires and what-not. I went to the station like a dummy the next time. I asked the question, how often does the tank get filled. They paused to think about it. Then said, 4 YEARS AGOOOOOOOO.

I too learned how to drain and clean the fuel system from Aaron at Hoye's video. He saved my day!


From that point on, I only go to stations on major truck routes with fresh clean diesel for road use. The turn-over in the station tanks is very often. Not a single problem since.

I do the Seafoam additive before and during winter, and the Gumout Multi-System Tune Up from Spring thru Summer. This gives the best results. I tried the PowerServe with so-so results and gave up on that brand.