Johnson GT175 temperature switch

[plenox]

I recently detected a problem with an overheat sensor switch on my 1989 Johnson GT175, model no. J175STLCEB, serial no. R08172422. I have bought a new one - OMC part no. 0583789 - but it is too long for the recess it fits in behind the water jacket cover plate. The supplier has checked and assures me it is the correct part, but it obviously isn't. Anyone know how I can check this and obtain the correct part?

 

[Dhadley]

Re: Johnson GT175 temperature switch

Do you have the old one out yet?

 

[plenox]

Re: Johnson GT175 temperature switch

Yes, but I had to dig it out due to the corrosion. The hole is now clean but there is nothing left of the original switch.

 

[Dhadley]

Re: Johnson GT175 temperature switch

Is the small round metal piece from the original sensor still in the hole by any chance?

 

[plenox]

Re: Johnson GT175 temperature switch

No. I have thoroughly cleaned out the hole which has a conical base, presumably drilled. I have scraped the bottom of the hole with a screwdriver and it is clearly the aluminium engine casting. The new switch I have been given is cylindrical and stepped, 15mm dia for 17.5mm then 12.5mm dia for 3.5mm at the bottom. Total length 21mm. (Sorry for the metric units). When the switch cylinder is in the hole it is quite a loose fit and stands proud at the top by a couple of mm (before the rubber seal is pushed down). The water jacket casing will clearly crush the thin metal cylinder if I bolt it down.

 

[Dhadley]

Re: Johnson GT175 temperature switch

Everything sounds normal except that its a "loose" fit. Usually when we install the sender we "seat" it with a screwdriver (push the rubber in the hole). We usually lube the outside with something like Electra Clean that will disapate. It will stick up slightly but the cover seats it with no problem.

 

[plenox]

Re: Johnson GT175 temperature switch

The rubber won't even reach the hole as the sender unit stands proud by a couple of mm. I don't know if the reduced section at the end is designed to deform into the conical bottom of the hole, but this would require applying some force to it which doesn't seem right on what is a fragile looking component. Is it possible you can confirm that I have the correct part no.? Thanks for your response by the way.

 

[Dhadley]

Re: Johnson GT175 temperature switch

That is the correct part number but that doesnt mean the part in the box is that number. The only suggestion I have would be to take it and the head to the selling dealer and let him verify the situation with Bombardier.<br /><br />Not much help, sorry!

 

[clanton]

Re: Johnson GT175 temperature switch

There are 2 part numbers 1 for the port cylinder and 1 for the strb cylinder. 0583789 and 0584592. They may have gave you the sender for a 60 degree engine

 

[plenox]

Re: Johnson GT175 temperature switch

The head isn't off but I'm taking the boat to the supplier on Saturday for him to see.<br />The port switch has one wire, the stbd one has two. The one I am replacing has two wires (stbd side)and has the part no. on the actual component. According to all theory it is the right part, but it is too long. I know the one for the port side is shorter but only has one wire. If I fit a port one, the tan wire could be connected into the loom but there would be no white/black wire to connect. According to the wiring diagram I have in a V6 workshop manual, each sensor only has one wire (tan) which connect together and then to something else which isn't labelled. These tan wires, when earthed, activate the horn. Presumably the white/black wire is what activates the engine speed limiter (S.L.O.W. system). I guess in desparation I could fit the port one to the stbd side and rely on the horn sounding if it overheats. I'm still convinced I don't have the correct part.

 

[clanton]

Re: Johnson GT175 temperature switch

0583789 stdb side, 0584592 port side.

 

[Joe Reeves]

Re: Johnson GT175 temperature switch

In addition to Clanton's reply....<br /><br />584592 is superceeded FROM #583441 and has but ONE (1) lead.<br /><br />584942 has two (2) leads extending from it and is a more metal like encased sensor.<br /><br />I have both and in looking them over quickly, it doesn't appear that they would interchange.