not using mid grade or premium any more

[exotion]

The stuff in the bottom of gas station fuel tanks has always been scary. I have no idea how much of it is ethanol. If the upper grades are indeed the cause of your plugs reading hot then you will soon know and then do please let us all know. Or at least me.

Will do I saw the ill results after one week of use so on Friday ill check again.

Do gas stations ever clean out the tanks id imagine over time some debris and bad gas or something would be down there.

 

[combatcarl]

Will do I saw the ill results after one week of use so on Friday ill check again.

Do gas stations ever clean out the tanks id imagine over time some debris and bad gas or something would be down there.

I used to work at a fuel station with above ground tanks. The pickups were about 3-4" above the tank bottoms, and with daily fills, usually every other day, I don't think the bottom accumulated much junk. We did use ALOT more regular than premium fuel, so I imagine that the higher grades may have had more deterioration than the regular grade. Also, this was before the ridiculous 10% ethanol requirement here. (OR) there should be a minimal amount of separation or water in tanks, and any particulate is filtered at the pump.

 

[Rivets]

Carbon buildup is caused by two things, how rich an air/fuel mixture you are running or using the wrong type of plug. Hotter running engines have less buildup due to more of the fuel being burned. The biggest reason you find more carbon in small engines is that the fuel ratio is not changing in the different operating conditions. Non adjustable carbs being used on single speed engines add to the problem, because of poor maintainance, such as a dirty air filter. Small engine plugs run hotter than automotive plugs, which will be indicated by a much lighter tip color, even when both engines are properly tuned. I also recommend SeaFoam as an additive, but for a different reason. There is no additive which can dissolve carbon, it is way too hard of a substance. SeaFoam will dissolve and remove the gums and varnishes in the fuel system, which lead to plugged ports and passageways and sticking parts.

 

[jekjr]

People here are starting to use 100 octane aviation fuel. A local shop that has been in business for something like 40 years highly recommends using it.

 

[Mad Mackie]

If that were true than all the gas stations would have pure ethanol on the bottom of the tanks?

Blending and phase separation problems surfaced years back when MTBE was added to gasoline. Ethanol blended gasolines while in storage will experience phase separation, for example a zero turn mower in storage off season. The operators manuals for both of my ZTRs, Scag and Hustler, instruct the operator to evacuate the fuel tanks for off season storage. Several years ago I was towing a 10,000 LB trailer with my 2003 Ford V10 van, I fueled in York, PA at a Sheetz Plaza. Several miles down the road the engine started pinging severely. The knock sensor did it's job several times and each time the engine power was reduced to the point where the engine didn't have enough power to tow the trailer. This was a Sunday afternoon. I was able to get to a nearby truck servicing company, being Sunday they were not open. Long story short, after doing an electrical diagnosis and a call to a local Ford dealer, evacuating the fuel from the tank was decided. Testing of the fuel determined that it was about 90% ethanol and other unidentifiable stuff. I filled up with 91 from a local gas station, went back and hooked up the trailer and got back on the road. Never got a return call from the manager of the gas station in question.:thumbdown:
Mad Mackie in CT:laughing::smile::biggrin:

 

[combatcarl]

People here are starting to use 100 octane aviation fuel. A local shop that has been in business for something like 40 years highly recommends using it.

Y'know if that's 100LL or unleaded? I know a station near me sells 100LL and 110LL.

 

[Mad Mackie]

AvGas is 100LL however the octane rating is derived by a different method from auto gas. I would not use Avgas in any small engine. The higher the octane, the later the burn starts and will still be burning when the exhaust valve or the port is starting to open on the exhaust part of the cycle.
Dispensing Avgas into a vehicle is forbidden by Federal law. Dispensing AvGas in containers of a certain size and larger, don't remember, is also forbidden by Federal law. I'm not the AvGas police, however I recall the aircraft sales/maintenance company that I retired from as an aircraft mechanic had a run in with the Feds with regard to dispensing AvGas to race car folks.

 

[combatcarl]

It's all anybody here runs it in, is sand toys and race cars. Most of the guys running it are riding heavily modded 2-strokes. Used to run it through a hod rod bug. Ran it through a 305 small block Z28 when the money allowed.

 

[Mini Motors]

Somebody already beat me to it, but I'll point out that any fuel tank draws from the bottom, including your mowers. The exception would be your gas can.

And I will point out again, that with engines where the timing can be changed, messing with different octane ratings is fine. As MM pointed out, different octanes burn at different rates, and a change in octane requires a change in timing, something that you can't do with a mower engine.

As for Sea Foam, you're right Rivet, it can't dissolve carbon. But as it's been explained to me, it won't allow any new carbon to "stick" around, and without further carbon build up, in time, any carbon there will burn off and go away, hopefully through the exhaust pipe without scratching anything.

 

[Winger]

The higher octane should actually burn cooler, not hotter. I would adjust your mixture if its possible and add a little more fuel. And usually it's only necessary to run the higher octane on higher compression engines.