2007 Mercury 115 HP EFI Four Stroke Fuel Problem

colbysmith

Had a mechanical problem with my subject outboard the other day, and thought I'd share it here for reference. I came back a week ago from a great vacation in the San Juan Islands, where the boat ran fine. Then this past Saturday I took it out to a local lake back home, and again it ran fine. Then day before yesterday I took it out, it started, but then died. I was able to start it again, but barely keep it running. Lots of smoke, as if it were a 2-stroke with too much oil! Put it back on the trailer and brought it home to work on. Spent several hours trying to figure it out. It appeared to be running very rich as I was getting a lot of soot in the exhaust. Tried pulling coil wires, and could hardly tell a difference. Gave up as it was getting very late. Next day, pulled the plugs and they were black. I have a "code" reader for the engine, and the only code that showed in history was one for Lift Pump Timer. I really did not want to take it in to the shop if I could help it. Studied my Mercury Shop Manual for the engine, and then spent several hours on the internet. Finally came across this bulletin:

http://www.marinemechanic.com/merc/distributors/mercurymarine/outboard/FuelSupplyModule%28FSM%29Troubleshooting.pdf

Reading thru it was mention of a Pressure Regulator reference hose in the Fuel Supply Module. Said If the line inside the FSM were to split, or become disconnected, fuel will be drawn into the intake causing the engine to run rich. Wasn't sure I wanted to tear into the FSM, but this sure sounded like the problem. Required pulling the outboards bottom shroud off, and removing the Fuel Supply Module to get into it. Sure enough, the reference hose was cracked. This is a tiny little hose and according to my local boat shop, caused by ethanol. Unfortunately, it's hard to find fuels without ethanol everywhere, so it is what it is!

Anyway, this must be a fairly common issue since Mercury has addressed it with the bulletin above. It's not that hard of a fix for anyone mechanically minded, but somewhat of a pain having to remove some things to get to it.

Here's another link that mentions the issue and has a fairly good diagram.

http://forums.iboats.com/forum/engine-repair-and-maintenance/mercury-mariner-outboards/634769-mercury-115-efi-4-stroke-2007-fuel-problems-fixed

Just glad the hose waited to split until I got home from the San Juans!!!

Colby

colbysmith · Posted: Sun Jul 13, 2014 12:38 am Post subject:

The little hose cost $25 at my local dealer. Seems pretty expensive for a short piece of hose and two hose clamps. But I probably saved a ton of money in labor costs, minus the broken VHF antenna that didn't fit through my garage wall... Sad

thataway · Posted: Sun Jul 13, 2014 12:42 am Post subject:

Good diagnosis and repair! For those who are not aware, Puregas.org has a list of most of, if all of the service stations which sell non ethanol gas. In Wa. State there are 196 stations. In Wi there appear to be about 580 ethanol free stations. In contrast Calif. only has 14 stations listed without ethanol. We try if at all possible to get non ethanol gasoline.

Hunkydory · Posted: Sun Jul 13, 2014 9:29 am Post subject:

Good work Colby & a great tip for those with that motor. Like Bob we use pure gas.org, which we got the tip from someone here on the C-Brat site several years ago. By using it, I have only put ethanol gas in the boat tank twice, though I have changed all fuel hoses from the tanks to the motor to ethanol rated & still wondered what trouble, I may be in for on the ones left under the motor cowling. Colby shows that it defiantly can become a problem.

Jay

colbysmith · Posted: Sun Jul 13, 2014 10:54 am Post subject:

I'll continue using the 10% ethanol during the summer, but I do switch to non-ethanol just before winter so the boat won't be sitting with ethanol in it during storage. Kwik Trip gas stations here tend to have what they call "recreational" fuel, in their premium. But suppose I'm just too cheap to run it. That and I don't always like going out of my way to find non-ethanol in many other locations. But with that, I also understand the problems. I also had one of those small gas lines in a chain saw dissolve too a while back. Most newer lines are suppose to handle the ethanol. (At least the ones rated for it.) All newer equipment is suppose to be rated for the ethanol. But there is still a lot of older components used... Sad

Sunbeam · Posted: Sun Jul 13, 2014 2:15 pm Post subject:

Good sleuthing and interesting reading, even though I don't have that engine. Nice of you to post in case someone else needs the info in future, too.

I've also been using the pure gas website to try to find non-ethanol fuel. I always try to mention to the station personnel why I've come to their station, and to thank them for carrying non-ethanol fuel.

I did have to buy ethanol fuel on Powell (on the lake), but luckily there is a station in Page that has the good stuff, so after the trip I drove to town and filled up a gas can with non-ethanol, then took the boat back out and ran the tanks and engines dry, put the good fuel in (plus stabilizer and Ring Free), and ran it through everything before again running the engines dry and draining the carbs. (I knew the boat was going to be in storage for awhile.) Bit of a hassle, but I feel better having done it.

journey on · Posted: Sun Jul 13, 2014 11:54 pm Post subject:

Why would any outboard engine manufacturer build an engine to sell in the USA and put a non-ethanol hose in? They must sell a lot of engines in California, and I haven't been able to find any ethanol free gasoline except for VP Racing gas at ~$10/gal.

There's one station in Orange County that claims their gas is ethanol free but tests prove otherwise. So be careful. I certainly don't know how you tell.

And I would bet that the local auto supply would have a hose that withstands ethanol and would sell it for less than $25. It's worth a try, now that you know what was wrong.

Boris

colbysmith · Posted: Mon Jul 14, 2014 9:04 am Post subject:

I agree with you Boris. I almost did just look for another hose.. the hose that had to be replaced was about the same diameter as the fuel pickup line inside my chainsaw. Don't remember what that one cost, but it would have been cheaper. (Of course it didn't have the tiny hose clamps, but probably could have purchased those a lot cheaper too..) Just didn't have a lot of time to do any research on what else might have worked, as I wanted to get it all back together and back out on the lake. Our boating season here in the midwest is short enough! With the regular fuel line, you can tell the difference fairly easy in regards to what hoses are suppose to work with ethanol. (They have the higher classification stamped on them.) But anything manufactured since the beginning of ethanol fuel, should have been made to withstand it! What I don't understand is we've been told to use many different additives in the past, that contained alcohol and I don't understand the difference in the various makeups of alcohol, ethanol, etc. Colby