'76 evinrude 55hp temp switch troubles

[wtarcher77]

My boat had been in dry dock for a couple of years. I own it with my brother. He installed a new impeller before we "revived" it & all seemed well. We went thru carbs etc...got er all cleaned up & made it 500yds from boat ramp.... Smoke was coming out of couling. It basically died as I shut it off. Upon closer inspection, the temp switch evidently spontaniously combusted and, I am now left with two wires & the switch floating around "cooked" in the head.

I have not done a compression test as of yet...which I will. The gasket under the thermostat cover (on the head) seems to have melted down some too ( maybe a homemade seal job by previous owner ?? )

So, before I go too far into this, Will this temp switch meltdown, kill the motor without fryin power packs etc...??

Is there any way I can jump the wires from the old temp switch & see if I still have fire??

After (hopefully) some repies to this post I am planning on replacing thermostat & re-torquing the head, in an attempt to re-re-reserect her, Any other suggestions would be appreciated.

[StratosRob]

Sounds like a stuck thermostat or falty water pump. Do you have a steady strem of water coming from the tail- tell ( pee Hole ) ? I do beleave that the temp. wire ( tan ) will go to ground when the switch is actavatied therefor giving you a warning from the warning horn. Not sure but I think im right. You might want to wait for someone more familar with this engine. just thought any help is better than none. Good luck

[F_R]

The temp switch and gasket are cooked from the motor being severely overheated. You must find out why it overheated and check for other damage. Most likely a water pump. The cylinder head and exhaust cover gaskets must be replaced. Just hope you didn't fry the pistons, which is extremely likely. All this has nothing at all to do with the power pack.

[F_R]

Before I catch heck, that should read the cylinder head gasket and exhaust gaskets. But, yes the head could be warped too.

[wtarcher77]

We had tested the motor with muffs all seemed OK. There is no "pee hole" on this motor I was told by outboard mechanic, "all water comes out through exhaust on the prop"....(I REALLY wish there was a hole):'(
A new Impellor was installed before we took it out..... so unless there was some sort of (new) blockage in the supply tube, the only thing I can think is that the thermostat is stuck.

Unless there is a horn on the motor itself, there is no overheat horn that I know of (it never went off anyway). I bought this boat 10 years ago & I do not know if the motor had been switched prior to my owning so a factory type horn that should have been installed, WAS NOT. Do they make an overheat sensor that just desinigrates & cuts power to the motor?

Yes there are....or ....(were) two wires out of it, one was a ground, the other a tan wire that went into the main harness. So if this were to disinigrate would that in itself kill the motor? Or do I have bigger & much worse trouble?

[F_R]

The warning horn is in the remote control. There is no ignoring it when it goes off. That's not to say that it ever went off, it might not be working. Or the temp switch may have been cooked by a previous overheating episode. The temp switch will not turn the motor off. It only sounds the horn. That's all. The motor quit because it was smoking hot. That expands and burns pistons and burns gaskets, killing compression and admitting water where it doesn't belong (if you ever get it to where there is any water to admit). To put it overly unkind and blunt: You may have a large piece of junk hanging on your transom. You need help to figure out if that's true or not. Believe me, I've seen a lot of them. And I have seen a lot of them where the horn never went off because the motor was running wide open with zero water pumping and burned up and siezed before the head ever got hot enough to set off the alarm. Just a few seconds at full throttle and no cooling will destroy pistons. Then, after the motor quits and sits there cooking and smoking the horn sounds! Too late!