My local source of ethanol free gasoline has dried up, and I’m now faced with using gasoline adulterated with ethanol in my 2002 Mercury two stroke outboard (115 hp). Dopers, what’s the straight skinny on this? I’ve heard often that using the adulterated gasoline in older outboards is very bad for the engines, but haven’t really been able to verify this as fact.
I really am not excited about buying a new engine, as they are costing over $10,000 (at my age, not exactly cost effective), and weigh at least 75 pounds more than the old one. Which is running perfectly, BTW. What’s your best advice?
You aren’t going to get a single answer for this because it depends on exactly what materials were used in the engine. Some older engines have no problems whatsoever. Others have problems with the ethanol corroding fuel lines, the o rings in carburetors, and all sorts of things like that. It all depends on exactly what material those things were made out of. Some were sensitive to ethanol corrosion and some weren’t.
I can’t comment on your specific engine, but 2002 isn’t that old (comparatively speaking). I would be very surprised if it had any issues with ethanol in the normal E10 or E15 concentrations (E85 on the other hand can cause all kinds of problems on your era engine). Engines older than 1990 or so are where you usually see the problems.
You are going to need to be more careful about keeping water out of the fuel tank. Also, since your boat has probably never had ethanol fuel in it before, there may be some gunk that has built up over the years in the bottom of your tank and the ethanol may dissolve this gunk, causing it to float up in chunks and end up clogging your fuel filter. Technically this isn’t an “ethanol problem” (it’s really a gunk problem) but it’s something to watch for. You may need to have your fuel filter replaced fairly often a few times after the switch to E10.
I wouldn’t expect any problems but would be looking at at new ethanol resistant fuel line and water separating filter at a minimum, the water separator will easily pay for itself the first time you have water in the fuel.
I haven’t had a lot of luck with ethanol gas, even when using the latest additives. My current theory is that I do have some problems with either fuel lines or gas tanks that are reacting badly with the ethanol. Anecdotally, a lot of other mariners are having similar difficulties.
Your best bet would probably be contacting the manufacturer. They may be able to recommend what to swap out, if necessary.
Thanks for the replies. I took the advice of contacting the manufacturer (which I should have done in the first place). They said that the only problem in my case would be possible water in the fuel, and that they recommend using the additive Stabil, marine grade - blue in color - in the fuel to prevent this problem. So this sounds like an easy fix.
We still have non-oxygenated fuel here in Minnesota for use in old cars and off highway engines but lots of people use the Ethanol blended fuels because they are cheaper.
Then when they get a slug of water through their system and subsequent engine damage they find the money saved wasn’t all that good an idea.
I had never heard of the Marine Stabil and am going to have to check that product out further. I do see the Marine grade needs to be added every time fuel is added.