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skifreak85353

Knock Sensor Spewing Water

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skifreak85353

Long time listener, first time caller here...

My buddy recently got into a '10 VLX, actually purchased from a good friend and fellow 'Crew Member - SkySkier. We've been lovingly using her all summer, much the same as John did. Yesterday, after about 1.5hrs or so of riding, we noticed steam. Killed the motor and started digging. Discovered the auto bilge wasn't so auto and there was a bit of water in the hull, enough to reach the motor and cause some steam - so we'll need to make sure the float is good and clear on the bilge. But, the more troubling piece of the puzzle is where the water was coming from. Water was sputtering out from around the front knock sensor on the starboard side manifold. Anyone ever heard of or experienced this? Any ideas on why this would happen and what we need to do to fix it?

We were going to try to pull the sensor, reapply tape, and put it back in to see if that fixed it, but from searching on here it appears that would be bad. Also, what wrench/tool is used to pull these things? Looks like they're pretty recessed and we need some sort of cut socket to accommodate the wires? Saw someone used a 7/8 box ratchet, but it may have been for a different motor.

Thanks in advance...

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wdr

Easy fix it is just a solid bolt into the block. Most likely it wasn't tightend all of the way after he winterized it. I would pull it, chase the threads in the block with a tap,clean the threads on the bolt and put her back in. If you want you can unplug the sensor and move the wires out of the way to make it easier to work on. I don't believe that you are supposed to use any thread sealant on it as it might degrade the sensors ability to detect knock (just what I have read on here). I have been using anti-sieze on mine as they can be a scary PITA to pull if they rust too much. Think my bolts are 9/16, either way don't use a Cresent wrench on them. Those damn things should be outlawed! :)

Edited by wdr

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skyskier

"Wasn't tightened all of the way after he winterized it?" That boat has never been winterized, So there! :biggrin:

Hey, when I talked with skifreak his main question was how to remove the wire which would allow him to use a box wrench or socket to tighten up the sensor. So???

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SmoothWaterMan

....Water was sputtering out from around the front knock sensor on the starboard side manifold. ....

Please define this location or sensor. "front knock sensor on manifold".... as this doesn't sound like a knock sensor to me.

pb

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skifreak85353

Team - thanks for the input. Looks like I had some bad info previously...I was told that what I thought was an o2 sensor was a knock sensor so I just went with it...a more accurate description of the issue was it appears water was spewing out from the o2 sensor. However, upon inspection in the daylight, the hose that was running next to the manifold had actually developed an inch long cut/tear right next to the o2 sensor. The water was spewing out of that hose and ricocheting off of the manifold right where the o2 sensor is, making it look like water was coming from the sensor. Comparing it to the hose on the other side of the engine, it appears that there is about a 1/4" clearance between the manifold and the hose where on the failed hose there was zero clearance. I'm thinking a combination of the heat and friction over time resulted in the failed hose. It's probably been trickling water for some time, but finally got bad enough to be noticeable. Engine temp always looked fine, never noticed it until we saw the steam Saturday.

All in all, $2 fix, and some good 'ol wrench time.

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Faceplant409

What hose was it?

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skifreak85353

hqdefault.jpg

Not my image, but the hose that parallels the right manifold. I assume its a return line of some sort?

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