What is an Evinrude/Johnson Temp. Switch & Tag Assyl. P/N 0386686??????

[jerseyboy1983]

What is this part and do I need it? I have a 1985 Evinrude 150 HP and this thing came out of Each water jacket cover I took off and I have no clue what it does and/or if I need it. I'm guessing its for the temp alarm which I don't have on my motor or I wouldn't of overheated mine. lol

 

[Joe Reeves]

Re: What is an Evinrude/Johnson Temp. Switch & Tag Assyl. P/N 0386686??????

Part # 386686 is a heat sensor which grounds out before the engine overheats to a point where damage occurs. If your engine overheated to a point where the engine seized, I suggest you replace them.

To check your warning system, (engine NOT running), key in run position (ON), ground out the TAN wire of the engine's wiring harness that normally attaches to the sensors. A warning horn should sound, and if it does not, find out why and correct that scenario to avoid a repeat of your troubles. If the sensors are not available on this site, check that part number on eBay.

 

[jerseyboy1983]

Re: What is an Evinrude/Johnson Temp. Switch & Tag Assyl. P/N 0386686??????

Oh dang. Thank you. And I didn't get a warning buzzer. It just shut down after overheating. Then after I took the heads off it looks like I blew the head gasket and maybe even a piston ring. I think that because I have a hard, silver and crystal looking crust build up on the head and the spark plug. But the cyl wall looks ok. I'm not sure what that build up is. I even lost all compression on that cyl and the rest are very low compression.

 

[Joe Reeves]

Re: What is an Evinrude/Johnson Temp. Switch & Tag Assyl. P/N 0386686??????

I blew the head gasket and maybe even a piston ring. I think that because I have a hard, silver and crystal looking crust build up on the head and the spark plug. I'm not sure what that build up is. I even lost all compression on that cyl and the rest are very low compression.

In all probability you had a fine spray of water entering that cylinder which would cause pre ignition, melted piston, etc. Unfortunately you're faced with a total rebuild job or engine replacement.