Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Work for a State Agency. Each Fall (Sep.Oct.) we do fisheries surveys on our lakes. The rest of the year this boat basically sits idle. Each season the fuel is treated with fuel stabilizer. Each month the motor is run in a tank just to keep things going. For the past two years on the first outing the motor stalled and we had to be towed.(20 years ago it was and adventure...today it is not funny). The motor is a 2004 115 h.p. Mercury four stroke. Mechanics scratch their heads, replace fuel filters and hoses and swear it is "fixed". Any ideas???

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Does it run ok after the first trip and tow home with no problems? Sorry just a little pun. Can you be a bit spacific on the symptoms that occured leading up to ?Stall shut of wont start? in gear driving losing power?

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Cute!! Two years ago it ran perfect in the tank before the outing, then would not start at the lake. Mechanics replaced hoses on the Fuel managemt system. I replaced the gasoline and the water seperator and it ran fine the rest tof the season. This year, it ran great on the "test run" and then crapped out a week later. Not surprizingly, it ran perfect at the mechanic shop after having to be towed in at night. At the lake it ran perfect for about an hour then without warning it stalled and would not run for more than a few seconds. Suspect fuel issues and/or deterioration of the fuel system components due to Alcohol fuel. There are virtually no places to buy non=alcohol fuel. Use fuel treatment religiously and replace filters regulalry. FRUSTRATING!!!!

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

I think at this point i'd stop suspecting the fuel and start looking for the real problem. Are your mechanics Mercury dealer mechanics or state shop mechanics?

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Although it could be a number of things worng causing this to happen First let me ask where the carbs ever removed inspected and cleaned? Sounds like the floats may be sticking at times leaving the float bowls empty when stopped or needle valves not seating flooding the engine out. The motor in general runs fine. It periodically seems to overload with gas flooding out the engine and fowling the plugs. In time it drys up and fires right up. I would think about having this looked into. Does the primer bulb get hard when squeezed?

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Fuel injected, electric fuel pump

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Bonified Mercury mechanics. Analyzed with computer, called Merc factory and all that jaz.

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Guess I,m out of this one any stabs at it anyone?

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

I had similar problems with my 115's. has the fuel vapor separator been removed to check for a clogged electric fuel pump filter? Even with all of the filters before the vapor separator the fuel in the unit can boil and cause deposits to form that get sucked into the filter when the engine is in the down position. When the engine is lifted it sometimes clears the screen and runs again only to clog again after running for awhile. I found an article that suggests a heat shield be placed between the separator and the engine to solve the problem. It solved mine.

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

This problem is really not that difficult given the fuel we are stuck with..The injectors should be cleaned every couple of years no matter how many hours are on them...sitting is worse than putting a 1000 hours on that motor. I have that exact motor and had a bad stumble that was taken care of when cleaned..Sent them to Brucato and you will get a fact sheet of how they performed before cleaning and how they performed after cleaning...This is the first line of defense and can't believe that certified mechanics didn't sent the injectors out...Then you can proceed with other parts of the fuel system if not fixed...kind of like trying to tune an engine and having low compression. The injectors must be cleaned and spraying the correct pattern...Please let us know the outcome....Linda Brucato is the best and I wouldn't send my injectors to any other company...

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

Here it is almost December. Thanks for the input. For those of you who may be reading this...Finally found a solution. The problem was in the fuel pump reservoir. The float was sticking. It is a timed fuel pump. It is supposed to run for 40 seconds, then rest until called for. The float was sticking and therefore the engine was essentially running out of fuel. Very frustrating. The fuel injector cleaning is probably a great idea also. Maybe just get used to the idea that with the alcohol fuels there will be problems till the manufacturers admit there is a problem and re-engineer their engins. Thanks again

Re: Fuel System Issues after storage Mercury 115 h.p. 4-stroke

I've had carb float 'stick' when using Sta-bil in the fuel. I switched to another brand, CRC product and haven't seen it again.

That could just be a reaction to the local fuel formula, I'm not a chemist. So I don't know what to attribute the real cause.

I've heard 'scare stories' claiming valves stuck to the seats and pulled the seats loose from the heads. Maybe someone is covering for a serious overheat, I don't know.

All I know is one customers Mercruiser, Webber 4bbl, stuck the floats 3 years straight til I switch stabilizer brands. I felt bad charging for carb rebuilds three years staight but I can't just give away carb kits and time.