1999 Merc 175 EFI

My 175 EFI started great as usual this morning, but then later on stalled out as I idled. I could not get it to restart. It cranks up, but just doesn’t fire. So I learned the tough way how to load a bassboat without a motor.

I am looking at the mercury book. It say that the electronic fuel pump will not work below 8 volts . Could this have been my issue? I did not charge the batteries last night after fishing yesterday.

Maybe fouled spark plugs? I have no idea. My mechanical knowledge is kindergarten level.

My first bassboat and definitely my first motor issue. Any help, ideas, or people to call would be greatly appreciated. I feel like a total DA for needing to ask so please be gentle.

Its not the battery unless your alternator is broken, the motor will not even turn over if the battery is under 10 volts and the alternator on your motor would have brought it up to 13.7 in no time. If you think that’s the problem throw your battery on the charger then try again in the morning before you try any of the other suggestions.

well its either spark, fuel, or air that is the problem.. first start with the easy check and pull the spark plugs. Use a socket wrench to loosen them then unscrew and take them down to the hardware store and get replacements. Make sure you get the same size. That is the cheapest thing to try and you should be changing them about every other year anyways so go ahead and change them now.

If you do not have a set already, pick up a set of muffs from a boat shop so you can run the motor at home using the hose.

If that still doesn’t work you need to head into the fuel… and you need someone more experienced with injection systems than me to help you there.

That is the exact motor I run, and to this point this motor has been a very nice motor. When you turn the key are you getting any beeping? I had one of those “what a dumb azz” moments the other night when I went to start the motor and she cranked fine, but made three quick beeps in a row, which I never ahve heard before. Kept cranking and tried giving her some throtle, nothing. I then inspected a bit closer and noticed that some how I had moved the emergency shut off switch. Flipped it back, she fired right off, what a dork!

My Merc 175 efi can be tempermental just like this. If I don’t high idle it to warm up for awhile it will do this at idle driving away from the dock.

Have you attempted to start the motor after this? If it ran fine, this is the same symptoms I face. When my motor sputters and dies, I take the motor cover off and let it sit for a few minutes. Periodically attempt to start at high idle with the motor cover off. It’s strange…

I’ve tried lots of repairs, but it’s just one of those things nobody has an answer for, yet.

OK, so I bought some of the flushing muffs and tried to start this again. It will not start. As it is trying to fire, there are beeps. Like you mentioned. I have the kill switch flipped up to run (that is where I think it should be), otherwise it would be down to off? I took out 2 spark plugs. Dumb question time (again) The tips were black and there was a black/brown oil in there. Does this mean that they are bad? Why the beeping when it is trying to start?

There should be 3 short beeps when initially turning key on to tell you the system is working. Here is 3 possible problems. 1. Low oil level in the injection system. 2.the oil injection pump may have failed or 3.the water seperating fuel filter is full of water. Here is a couple things you can look at. Take off your top cowl & from the front of the engine you will see a small black box with a red light on it.Turn the key switch to the ON position & check to see if the red warning light is on.If the light is on, the water seperating filter is full of water.Drain or best option is discard & replace. Also check oil level in the engine mounted oil reservoir tank.If the oil level is not to the top of tank,the problem is low oil level.There is a float on there that sends a warning signal if low oil levels become present.Another thought is make sure the cap on main oil reservoir is tight & engine mounted tank is SNUG. Make sure to not over tighten the engine mount reservoir cap if you remove it,or you can crack it which makes a mess in the engine. Hope this might help.

There should not be oil on the spark plugs. At this point I would take it to a marine shop and have them look at it.

I took the spark plugs to R&R marine, they told me that the VST is stuck open and flooding out. Any opinions about their service department?