Posts: 363
Location: SW Ohio | sworrall - 4/3/2019 7:31 PM
Please clarify what you mean by the 'added fuel required to compensate for the ethanol', are you referring to the fuel rails?
Thanks for the clarification.
There are older systems (most still on the road/water) that have a tendency to run lean (or leaner) when run on ethanol added fuels. Since they are not closed-loop systems there is no way for the ECM (or old carbs) to tell that the the AFR is off. Ethanol does not burn at the same rate or provide the same power as straight gasoline. If the ECM programming has not been designed to compensate for the ethanol content there can be a tendency towards detonation (knocking) under heavy load. That's where a lot of the additives come in to offset the effects.
Another thing, other than ethanol, is the supposed "nitrogen enhanced" fuels that Shell had out. While it may work well in cars, this fuel caused severe issues in air cooled motors. Cylinder and head temps were much higher when these fuels were used resulting in shortened engine life. We ran a lot of tests on Harleys that had heat issues that went away when switched off of Shell fuels. Head, oil and exhaust temps all went down, and that is a good thing for any engine.
Yes, our outboards are not Harleys and they are not air cooled. But they are closer to air cooled than a controlled water cooled system of cars. They are run at WOT for longer and give very little advance notice of an impending catastrophic failure. Excess heat is the main culprit.
While i don't like to use any ethanol added fuels in my outboard or bike, I don't have much choice as there is no straight gasoline fuels near me. I use additives to prevent any issues that may arise from ethanol, especially when on the road. At home I stick to the same gas stations each time I fill up. |
