I was out at the lake this past weekend. Boat ran good for 2 miles. Pulled up to my spot and noticed engine was idling very rough. I went to put the boat in neutral and it was very very hard to do that. Once it was in neutral RPM'S shot up to 2000 and my alarm sounded so i turned it off. Went to fire it up and could not get it to start. Had to be towed in. I could smell fuel and it was very strong. Got the boat back on trailer and when we tried to start it same thing. It would crank but would not fire up. I went to the back and noticed i had fuel coming out the lower unit and some dark looking oil. Any idea what the problem may be?

I would suggest taken it to a platinum mercury dealer and letting them run diagnostic on it. I made the mistake taken to a dealer that was parts changer and it cost me dearly. just my .02 goodluck...

More than likely you have had diaphragm fail in one of the regulators or the tracker valve either way you are getting fuel into air side of system thats why it was idling so high, now that it will not start it is not building the correct of if any air pressure The reason the warning sounded was it hit the overspeed warning in neutral....OPTI

I just saw the light bulb over my head appear. Opti probably nailed it something in the rails failed.

I read this after the OP posted , I was tempted to post something but it woulda been wrong.

Thanks for input guys. I was thinking it may be something with the tracker valve as well. I had a pin size hole in one about 2 years ago but it never left me stranded. It had a rough idle and sometimes it would die on the first start up. Once started it ran good on the top end. I believe the last tracker valve installed was the purple one. I should have the boat in the shop soon. My mechanic is about 2 weeks out.

Just wanted to report back. I went ahead and pulled the tracker valve off fuel rail. It is sliced pretty good. I’m going to order one today. This is the second one in 2 years. Any ideas why this happened again. Anything I’m doing wrong? Seems like this is a problem with the mercury Pro XS. Is there anything else i should address? Or can I just put the tracker valve in and be done with it?

Thanks OPTI!! Looks like you nailed it.

report back after you test run it!

Will do Tiltman.

Installed tracker valve today. Engine sounded and ran like a champ.

Nice ! Was worried is was worse , like broke reed or worse

OPTI doesn't miss much, if anything at all.

Glad i could help brother