HI Everyone,

This is my first time posting and I'm hoping someone can provide me some help. I have a 2004 mercury optimax 115hp. When I received my boat out of storage, it was not running properly. It was essentially stuck in guardian mode. Since then I have done the following things:

1) Removed all the gas from the tank and put in new gas.
2) Replaced the fuel line
3) Replaced all the spark plugs
4) Took apart and cleaned the VST
5) Replaced one of the coils

The first 4 items did not get it out of guardian mode but when I replaced the bad coil it started running great. It ran great for a couple of days and then would start to die at full throttle. Since then the issue has gotten worse and it has issues at full throttle but also stalls when it is idling. I ended up borrowing a mercury vesselviewer and when I ran it, it returned the following fault codes:

1) 451-25
2) 701-24
3) 541-24
4) 711-24
5) 1012-24

Unfortunately, I don't know what exactly those codes mean and what I need to do to remove them. Also, it's important to note that I am not receiving any beep warnings from the motor. I would appreciate any help or feedback anyone can provide. Thanks!

Hi Camalot.

Thanks for responding. To be clear, what you are saying is the codes I pulled with the viewfinder have no value and I need to get a scanner to pull DTC numbers, correct?

zfrick, Where are you located. I have a Rinda Scan Tool.

Novi, Mi.

If you were in West Michigan I could help you. I don't get over that way ever. Sorry

Youre going to need a scanner to check for codes.

What did the plugs look like that you took out when you put new ones in? Were they fouled?

Have a fuel pressure gauge set you can use to check the fuel pressure?

Is the buzzer going off at all?

Ok, thanks anyways Old Navy. If you come out this way let me know.

The bottom plug was fouled. The rest seemed ok but I replaced them all.

I've checked the fuel gauge a couple times. I just re-checked it tonight and it looks like it's reading a little below 110psi. It's hard to tell because the fuel pressure gauge I loaned from autozone only goes up to 100.

It was strange when I tried to check the pressure on the VST it showed 0. I've checked it before and the pressure was between 20 and 30psi. Do you know what the pressure is supposed to be at?

The buzzer is not going off anymore. Before I changed the fuel and cleaned the VST is was giving me the 4 beeps every 2 minutes alarm.

4 beeps / 2 min is the warning for the oil tank sender. They go bad all the time. - Big piece of junk cause warning horn beeps.

Unless it was stuck or u were low on oil. But 9 out 10 its the sender going bad.

the best tip I can give about the Optimax - always check fuel and air pressures to spec it takes a special gauge but more important is HAVE THE AIR INJECTORS cleaned and tested - Been cleaning and testing opti max injectors and Opti AIR INJECTORS all day today. The air injectors are huge issues - carbon up so bad that it can cause failures. this one is under 250 hours power head failure. The air injectors extremely restricted, BEFORE and AFTER today . Just showing one set of the air injectors for an example