Re: Should I worry about E85/ethanol in my older motor?
Sea Foam is a great additive to put on your gasoline to keep things cleaned out and the engine running tip top. Most auto parts stores have it.
Different rubber compounds are made to resist certain chemicals. Back when that engine was built, alcohol was not one of the chemicals that designers had to consider in the fuel system. Therefore, many have mentioned that deteriorating rubber parts on older engines can be a problem.
My opinion: I don't know when Merc went from high pressure fuel lines to just plain rubber with a nylon tie wrap to secure onto a hose barb somewhere down the line. If you have the old original style reinforced hoses with metal crimped connections and want to replace your fuel lines no biggie. Just remove the lines and go to the auto parts store and get some fuel line of the proper dimension (1/4 or 5/16 ID) and some hose barbs to fit the hose and threads to screw into the treads where the old lines were connected. The hose barb is nothing but a threaded fitting on one end and a hose adaptable round snout on the other. You just push the hose onto it and lock it down.
If you can find non-reinforced line (Like vacuum lines used to be) that is all rubber with no fabric mesh then you can use tie wraps to clamp the hose onto the barb which is the easiest way to do it. My 2002 90 is plumbed that way. Otherwise if you use the reinforced hose you will need something more rigid like a SS hose clamp. I'd go for the non-reinforced personally.
Next thing could be the fuel line from the tank to the engine including the squeeze bulb. If the line is gray they deteriorate and should be replaced sooner than later. BTDT
Other than that the fuel pump diaphragm would be next on the list.
These replacements are inexpensive and may take an afternoon to complete. Worth the time. Iboats or Sierra should have your fuel pump diaphragm. If in a kit with the valves and all, it is most important that you put the check valves in properly so that when the engine tells the pump to suck and hold it does and when to blow and hold it does. Just recording what you have and reading the directions in the kit should make a walk in the park. I did mine this last year.
Edit: After Laddies reply, I realized you were talking about E85. I was addressing E10. My Merc manual says that my engine is compatible with E10. My engine is lubricated with oil at the pint to 6 gallon ratio (50:1) for pre-mix. If I still had my oil pump hooked up it would be 80:1 at idle to 50:1 at WOT, dictated by the pumps performance curves. I use either Pennzoil or Merc TC-W3. My manual says TC-W2 or TC-W3 is recommended oil but being printed in '97 the W2 has since been dropped. Recommended gasoline is unleaded 87 octane min. at the 50:1 mix.
It goes on to say that fuel pressure is 2.5 psi at idle and 6 at WOT so it doesn't take a lot of hose clamping to hold 6 psi in the lines. If you are already running E10 then you know how your engine runs on it and whether or not your carbs or anything else need attention. If it runs fine then I usually "don't fix it if it ain't broke" as the saying goes.
Again, my opinion and how I treat my equipment.
Mark
