Mercury sport jet question

[wingtime]

Ok it's not an Aquaport but it is a boat.... the rat boat! and I have a question for the Merc experts.     I took the jet boat out on the lake today for a test run.  It has the Mercury sportjet 175XR2 that is basically a 2.5L Merc power head mounted inboard on a jet drive.  It runs great...  hauls tail....  It seems to load up or something after a long idle but it starts right up if i give it some throttle.  But thats not the question.  The questions I have is I get four beeps exactly every two minutes.  I know it is not a overheat and I know it is not a oil alarm.  What the heck is it?  This thing has the TKS module that is supposed to make starting easier.  I suspect something is up with that.

[seabob4]

Bruce, read this thread from continuouswave...http://continuouswave.com/ubb/Forum3/HTML/010414.html

[wingtime]

Yeah I've read that thread before.  It's all over the map.  The TKS is different than the normal Merc oil warning module.

[seabob4]

Good boy, you've done your homework...

[fitz73222]

Agree on the warning module, had to replace both of them on my 115's. Same constant beeping. The module monitors temp and low oil. Try disconnecting the low oil wires and see if you still get the beep. Then do the same with temp switch wire. If it still beeps, you know its the module. I believe your engine also has a rotory motion sensor that checks for rotation of the oil pump shaft; you may need to isolate that as well. If you had an oil pump problem, we would be having a different conversation now.

[wingtime]

Fitz,  The TKS monitors the oil level in the cap of the engine mounted oil tank, the magnetic sensor for the oil pump shaft and the engine temp. It also controls the enrichment solenoid, and timing below 3000 rpm depending on engine temp to make it easier to start. So it is an alarm module and a easy starting controller in one.

I replaced the oil reservoir tank cap with one I had since the wires looked suspect. I pulled off the oil pump itself. It turns freely by hand, the shaft turns when you crank the motor, and I took a pic of the plastic drive gear that you can see in the block and it looks good. This motor only has 60 hours on it so I wanted to make sure nothing was seized from sitting. Is the oil cap float a normally open or closed switch when the tank is full?

The annoying part is this is four beeps exactly every two minutes and the merc service manual doesn't mention that. It just says a constant tone is a overheat alarm and a constant beeping is a oil alarm. It does mention that the engine can be run with the module disconnected. Ih and the Tks module costs $500 bucks!

[GoneFission]

The 4 beep alarm on some Mercs can indicate water in the fuel filter - Optimax motors do this a lot.  Take the fuel filter off, drain it out, and see if the beeps stop.

[Blue Agave]

The 4 beep alarm on some Mercs can indicate water in the fuel filter - Optimax motors do this a lot.  Take the fuel filter off, drain it out, and see if the beeps stop.

^X2 on water in the fuel water separator. I believe yours has carbs so I don't believe it has the mercury fuel/water separator as part of the fuel system.  You can always call Mercury and ask.

[wingtime]

The 4 beep alarm on some Mercs can indicate water in the fuel filter - Optimax motors do this a lot.  Take the fuel filter off, drain it out, and see if the beeps stop.

John,   Your exactly right the Optimax and I think EFI motors do that.  Problem is this is a carburetor engine with just a simple inline fuel filter.  

[wingtime]

You can always call Mercury and ask.

Merc has a tech help line?

[Blue Agave]

920-929-5040, it always helps to have your serial number.

[wingtime]

Wow hats off to Mercury.  I submitted a online form for customer support and I revived a call in less than 20 minutes!  The tech suggested we are the right track looking for a bad sensor such as the low oil sender.  It also could be low voltage causing it which is easy to test.  He said he while it could be a bad module he doubted it is since it is giving such a specifically timed alarm.  So unfortunately I didn't get a specific solution.