2001 Indmar knock sensor threads corroding

[utmba95]

I have a raw water cooling system on a 2001 Launch with 5.7L Indmar, and I run in fresh water. My knock sensor threads are the only place I notice corrosion, and they don't seem to last as long as they used to. Is there perhaps a sacrificial anode somewhere that has worn out and needs to be replaced?

[michael hunter]

I have a 08 Nautique 210 5.7 the knock sensors screw into a adapter that screws into the block. You may want to check with PCM .

[utmba95]

I have a 08 Nautique 210 5.7 the knock sensors screw into a adapter that screws into the block. You may want to check with PCM .
Thanks. Any idea what type of material the adapter is?

[michael hunter]

looks like steel I noticed a little deterioration on the end but the boat has over 1200 hours. dorman and ebay has them . Google knock sensor adapter.

[utmba95]

Anybody know if there is a sacrificial anode on a 2001 Indmar?