1998 Mercury Mariner 150EFI will not start

I was running my boat the other day and everything was working fine as I could tell. I cut the motor off for a while to fish and when I tried to start it back up, it would turn over but not start. I had it towed in and have been trying to figure out what is wrong with it.
After turning it over for about five seconds, I'll give it a few seconds to rest and then try turning it over again. At this point the engine temp light and the warning horn will go off continuously until I cut the key off. I have a repair manual, but it is kind of unclear as to what this code could mean. I was thinking it has something to do with the oil system, but I really have limited experience working on these motors. There is no leaking anywhere on the motor, but it does seem like it takes too long to prime the motor, like there is a leak in the fuel line, but I don't think this would cause the warning system to sound.
Any help anyone could offer would be greatly appreciated, so I don't have to drop the money going to a repair shop.

Re: 1998 Mercury Mariner 150EFI will not start

Even a suggestion pointing me in the right direction would work...

Re: 1998 Mercury Mariner 150EFI will not start

Go to the Engine FAQs Forum, Jam. Do the troubleshooting in "Outboard won't start".

Good luck, and let us know what you find.

Re: 1998 Mercury Mariner 150EFI will not start

Not to insult you but check the "kill switch" to see if it is tripped. If it is ok, turn the key to "on" and do you hear the electric pump run for a few seconds and stop?

Re: 1998 Mercury Mariner 150EFI will not start

Kill switch is fine. I'm about to check to make sure it's getting spark, but the fuel pump is coming on and not shutting off. I have checked for leaks in the fuel system, but haven't been able to find any yet.

Re: 1998 Mercury Mariner 150EFI will not start

Ok, I have an update. I didn't see this problem initially because I had the engine cover on but when I have the water running through the motor (waterhose hook up), I have a leak at one of the exit lines from the block. I'm guessing I just need a new gasket and to re-torque the bolts, but all the part suppliers in my area are closed for the holiday. My question is: Is the warning system intricate enough to prevent the motor from starting because of this, or is there probably something else going on here?
I took a picture of where the water is leaking. It's marked by the red tape.

Re: 1998 Mercury Mariner 150EFI will not start

Pic

Re: 1998 Mercury Mariner 150EFI will not start

Is the warning system intricate enough to prevent the motor from starting because of this, or is there probably something else going on here?

Click to expand...

Nope...The leak is at the t-stat housing and the seal around t-stat is what seals housing thus no gasket. Check your spark and if ok check to see if you have fuel, as pump should should shut down after about 15-25 seconds. When pump is running check pressure on schrader valve on VST tank. If no pressure or lower either float in VST is stuck shut not allowing fuel to fill or regulator has failed, pressure should be 34+psi

Re: 1998 Mercury Mariner 150EFI will not start

I also doubt that is the main problem, the water leak is most probably just something that can be visually seen and the most obvious when looking at the engine run.

Re: 1998 Mercury Mariner 150EFI will not start

Ok, I just checked and do not have a spark, so I suppose I'm gonna fix the leak first and go from there. I'll do a more thorough chec on the spark on all cylinders tomorrow, but since there are separate coil packs for all cylinders I would figure that something else is going on here. Thanks for the info, and I will check everything and keep you updated.