05 Merc 250XS Fuel Leak and Misfire.

[MIKEinGA]

Ser # 0T998584

Idling out this morning, experienced rough idle. Started back to the ramp and throttle surged on it a few times. I shut it off, cranked it again and it was idling way too high...1800-2000 RPM. I shut it down and fished for a while. Cranked it later after about 45mins. ran fine. Planed off and went about an 1/4 mile across the lake. Shut down and fished for 2 hrs. Started smelling gas very strong. Noticed fuel running from beneath the skirt into the water. I used trolling motor to get back to ramp. I cranked engine to attempt to load the the boat and it was idling way high again. Loaded boat with rolling motor and inspected beneath the cowling in the parking lot. Found water sensor on bottom of vapor tank pouring fuel from it. It looks to be degraded from ethanol. The sensor seems like an easy fix but the engine is acting like the throttle position sensor is going bad also. I have replaced it within the last 2 years when it exhibited almost the same symptoms, minus the fuel leak. Am I experiencing 2 separate problems, or is the severe fuel leak causing my problems?

[JOE54]

most likely way over rich air induced to intake replace that sensor and restart report back

[EuropeanAM]

^^^ This.

Make sure that no remaining fuel vapor or liquid remains inside the engine cowling BEFORE you attempt to start the engine again. Leaking fuel carries with it a RISK OF FIRE OR EXPLOSION.

[MIKEinGA]

I installed a new water water sensor in the bottom of the vapor tank and fixed my problems. The sensor was very hard to remove. It actually broke off in the tank in the removal process.. I drove flat screw driver into the old sensor and was finally able to un-screw it. Thanks for the help...

[JOE54]