What is this?
 

I can not get one of my plugs to go in. The plug has threads on one
End and a piece on the other that plugs into it. Any clue?

[URL="http://m1069.photobucket.com/albumview/albums/jrh1010/Mobile%20Uploads/IMG_7164.jpg.html?o=0&newest=1[/URL]

: ) I give up. I'll post a pic tomorrow if no one has a clue.

http://mob1069.photobucket.com/album...s/IMG_7164.jpg

If this is the piece you're talking about, it's a knock sensor. Detects predetonation which the ignition box or ECM will retard timing when it occurs, avoiding engine damage like cracked pistons and rings, damaged bearings, etc. If your ignition setup uses this, it should be installed. Commonly installed in block drain holes, do not replace with a drain plug unless you're running an old style ignition with no provision for a knock sensor.

Ok, u haven't had our boat out all year o_O been working on getting. Pool
Built. But I still haven't replaced this part. Can I put a drain plug in till this part comes in? Will the engine even start?

Don't run it without. It looks like a standard 350 knock sensor, I'd cancel the order and go down to an auto parts store to get on the water sooner.

Thanks J. I'll do that.