How to replace an overheat sender?

[oxbeast1210]

Hello guys,
1989 Evinrude tracker xp pro 150 hp model : te150slcem is what i have

I'm back I'm so close to getting my boat in the water thanks to this community I just need to resolve one last issue . I need to figure out how to replace the overheat sending unit i believe it is faulty my alarm is constantly on even before i start the motor i tracked all the wires and fixed all possible grounds i noticed that if i unplug one of the wires that goes to the switch/sender on the right side the horn stops the only problem is that the wires go into what looks like a rubber plug and i didn't want to just tug on it or try pulling it out without first asking you guys what the proper way is
also where can i buy the part?
thanks

 

[Joe Reeves]

Re: How to replace an overheat sender?

Remove the water jacket cover from the head first.

 

[oxbeast1210]

Re: How to replace an overheat sender?

Darn i was hoping that would not be the case.
i think that im in over my head .
I'm worried that the bolts holding the water jacket may snap
is there anything you can recommend ?

 

[jgriner]

Re: How to replace an overheat sender?

Darn i was hoping that would not be the case.
i think that im in over my head .
I'm worried that the bolts holding the water jacket may snap
is there anything you can recommend ?

pb blaster http://www.iboats.com/Blaster-Chemi...598420965--**********.492935616--view_id.4424
just be ready pb blaster doesnt smell like wd-40

 

[Craig-]

Re: How to replace an overheat sender?

Darn i was hoping that would not be the case.
i think that im in over my head .
I'm worried that the bolts holding the water jacket may snap
is there anything you can recommend ?

PB Blaster, and tilt motor so it can run down the bolt. Tap on bolt head and let them soak overnight, repeat. Don't use a big wrench, use a cheap 1/4" socket, better off breaking it than a bolt. Crack loose and soak again. If you are real good with a torch, bolt can be heated then sprayed, only heat the bolt. Don't break a bolt, seek professional help if you can't get them loose.

 

[Joe Reeves]

Re: How to replace an overheat sender?

I use a hand held propane torch..... keep a fire extinguisher and a garden hose handy.

The majority of those bolts usually come out with no problems. The difficult ones, heat the aluminum area around the bolt to expand it away from the bolt which normally causes the bolt to loosen.

 

[oxbeast1210]

Re: How to replace an overheat sender?

Thanks a lot guys I'm going to give it a shot before I pay someone else to do it
where can i find PB Blaster locally what store would carry it?
thank you

 

[Craig-]

Re: How to replace an overheat sender?

Keep in mind the melting point of aluminum is just over 1200F, a steel bolt is around 2600F, stainless is a bit higher. The idea is to break the corrosion bond between the two metals. Heating will cause thermal expansion of both, actually squeezing them tighter together while hot. A sudden quench with penetrating oil contracts the hot metals, breaks the bond and allows penetration of the oil to the treads. The bolt will make a squeal sound when turned loose with a wrench, at this point I oil again.

 

[Craig-]

Re: How to replace an overheat sender?

Thanks a lot guys I'm going to give it a shot before I pay someone else to do it
where can i find PB Blaster locally what store would carry it?
thank you

Harbor Freight carries it at my local store, the price is cheap there like everything else.

 

[Will Bark]

Re: How to replace an overheat sender?

If you don't have a Harbor Freight Walmart auto section or any automotive parts store will have it.

 

[oxbeast1210]

Re: How to replace an overheat sender?

Awesome i think there is one of those stores in Pensacola
wow just saw the price for the send/switch and 90 bucks seems a bit steep lol
the one on the left side is only 30

 

[Wishiniwuzfishin]

Re: How to replace an overheat sender?

Autozone/car parts store should have PB Blaster also. "Kroil" ("the oil that creeps") is another good one too. Not sure where you can get it...I used to get it from the machine shop where I worked.

 

[Craig-]

Re: How to replace an overheat sender?

Awesome i think there is one of those stores in Pensacola
wow just saw the price for the send/switch and 90 bucks seems a bit steep lol
the one on the left side is only 30

The one with 2 wires is always cheaper than the one with one wire, doesn't make sense. Remove yours before ordering the new one, there should be no continuity through it cold.

 

[oxbeast1210]

Re: How to replace an overheat sender?

ok i got the blaster but I'm going to wait until i have the switch and gasket before i take it apart ill start soaking the bolts though. is there an alternative to the switch ? maybe something that can read the temp from the outside and let me know when its overheating? i don't want to just disconnect it and wing it but im on a really tight budget at the moment and cant justify the 90 bucks at the moment or does any one know where i can get it cheaper? i know the 90 bucks would save me a lot more i did overheat and wasn't alarmed so if need be ill just keep it out of the water until i can afford the parts
thanks guys!!

 

[oxbeast1210]

Re: How to replace an overheat sender?

also is there a chance that maybe its just stuck or are they a one time use thing?
thanks

 

[oxbeast1210]

Re: How to replace an overheat sender?

Ok guys i took the plunge everything went smooth in removing the water jacket but alot of the casing that held the sender/switch in place is still stuck in there i tried prying it out but the outsides were to brittle and just broke so now i am just left with the bottom part and don't know how to take it out? should i apply a lot of heat or continue bashing at it?
thank you

 

[Craig-]

Re: How to replace an overheat sender?

also is there a chance that maybe its just stuck or are they a one time use thing?
thanks

You can check continuity without removing it. Meter set on ohms, put one test lead on the unplugged wire from switch and the other on a good ground, needle on meter will not move with no continuity, in which case switch is good.

 

[oxbeast1210]

Re: How to replace an overheat sender?

Ok so i did the test you suggested and the switch is definitely bad so i tried taking it out but only the two round magnet looking pieces that are attached to the wires came out and what i believe to be the casing for it is still in there
what came out looks like this ?..

 

[Craig-]

Re: How to replace an overheat sender?

Ok so i did the test you suggested and the switch is definitely bad so i tried taking it out but only the two round magnet looking pieces that are attached to the wires came out and what i believe to be the casing for it is still in there
what came out looks like this ?..


View attachment 65881

What's left in there? Got a picture? Plastic casing should come out with it.

 

[oxbeast1210]

Re: How to replace an overheat sender?

Ill post some pictures for you in a second the casing didn't seen to be plastic more like metal the outside of it seemed brittle but the bottom is pretty solid
unless im digging in to far and no longer messing with the casing!!