2013 mercury 150 XS Pro will crank but not start, any ideas?

The boat has sat for quite a few months, I tried to crank it up and the batteries were completely dead, so I charged them up and tried to start it up and it just wouldn’t turn over. I released the pressure out of the bottom valve on the back of my motor and it started right up multiple times. Now it won’t start at all again, it almost starts but it just keeps cranking and cranking.

Batteries are rather new, fuel filter has been changed, spark plugs are brand new, I drained the gas that was in it because it was pretty old and put new gas in it, prime bulb is brand new, gas lines are brand new. I just can’t figure out why it won’t start. Any ideas?

Mercury’s are very picky about battery power. Even though you charged them up, they may be still too weak to actually start the engine.

I’d suggest buying a Yamaha or Suzuki. Shouldn’t have problems again. That sounds like a typical merc to me.

Sounds like the motor isn’t getting gas. Might have been something wrong with the brand new gas lines and bulb you put in.

The boat never had problems starting up a few months ago. I have 2 batteries for it. One is completely charged up 100% it’s pushing out about 12.6v which I know is enough to power it up I thought. They’re the same batteries I’ve had in it since it was working perfectly fine.

Any chance it could be the kill switch?

I don’t have a kill switch on this boat

PM – iowaboy1.
He’s prolly a few fingers deep in old #7 but thats when he’s at his best

Michael Alexander wrote:

I don’t have a kill switch on this boat

No tether?

No tether. Just straight key to ignition and turn on

That era of motor,and depending on who built the computer,must have batteries with a minimum of 1000 cranking amps and I dont give a crap if youve been getting by with less.
So,shooting from the hip,MUST have spark and proper fuel pressure all other things considered.
Could be a failing fuel pump (s),bad pressure regulator,failing primer bulb/hose if employed.

Todays injected motors are too costly to start throwing parts at,a systematic diagnostic approach must be taken,if you dont have access to proper tools,you are wasting time and money.
You mentioned old gas,could be pump rotor lock from a glazed rotor,very common problem,and I will say this,in todays world,fuel issues are nearly 100 percent of the problems we techs see.

Dont mean to come across as an asshat,but if you figure your fishing pleasure is worth 50 bucks an hour and you fish 3 hours a day,thats 150 smackers you could have paid a tech to diagnose,and if you know which end of a screwdriver goes in into your hand, a good helpful tech will walk you thru things,,and,if it is a fuel issue,dont use zipties or worm drive clamps on the high pressure side!!!

I will ad,if you drained the vst or fuel supply module and it started multiple times for a bit and now it wont,sounds like either a float is stuck or sank flooding it,,or,the pressure regilator hose IF routed inside of the pump module is rotted and sucking raw fuel once the module is fuel again,but there I go,shooting from the hip without having it where I could run tests.

I do have a tech coming out Monday to look at it, but I was just curious if I could hop on here and ask the community that maybe I am just missing something simple.

My spark plugs are brand new, all fuel pumps come on when I turn the key. I replaced the gas with brand new gas and the priming bulb is brand new along with the gas lines. As far as my batteries pushing out 1000 cranking amps I’m unsure of. I guess I need to look up how to measure that. I’m sure I can do it with a volt meter.

It started up before I drained the fuel. But only when I released pressure from the bottom valve in the back of the motor. But now it won’t start again. So my thought was the gas has been sitting in it for months so I probably need to drain it and put new in it. But that didn’t help either

Don’t take offense…..it’s been a long week. It’s really hard to diagnose a issue when you don’t have the motor in front of you. Just curious where are you located that you have a tech coming to you?

Michael Alexander wrote:

The boat never had problems starting up a few months ago. I have 2 batteries for it. One is completely charged up 100% it’s pushing out about 12.6v which I know is enough to power it up I thought. They’re the same batteries I’ve had in it since it was working perfectly fine.

What’s the voltage while cranking. A bad battery can show 12.6v, but drop well below 11 when under load.

I’m going to be testing this today to see

If it’s cranking I wouldn’t think it’s power issue. Possible fuel pump maybe?

Michael Alexander wrote:

I don’t have a kill switch on this boat

I’ll guarantee you have a kill switch. Tether may not be attached, but there is a kill switch.

-J.