Melted Thermo Switch

[Jeremy T]

Hello Everyone, I recently was given a 1971 Johnson 50 model number 50ESL71S. I do not know the history of the engine. It turns over but has signs of overheating. The Thermo Switch is completely melted and the rubber has run down the side of the engine. Is this going to be a required item in order to see if the engine will start? Thanks for any advice.

 

[boobie]

Re: Melted Thermo Switch

You don't need it to start it but if you ever get it running be sure to replace it.

 

[woody66912]

Re: Melted Thermo Switch

One more thing check for melted wires, mainly the main engine harness that is wrapped in black tape and the orange wires to the coils. If the orange wires shorted to the block while it was running it could have lost that cylinder.

 

[Jeremy T]

Re: Melted Thermo Switch

Thanks for the responses. I am currently inspecting everything. My next step is to remove the cylinder head cover and check the cylinder walls and piston conditions. I will keep you all up to date and post some pictures.

 

[Jeremy T]

Re: Melted Thermo Switch

So I have tore the engine down and one of the cylinder walls has a groove in it that just barely catches your finger nail. I want to get this engine bored .020 or .030 but am having a problem finding new pistons. Does anyone know where I can get this part? All websites I have found say the part is obsolete. Engine is a 1971 Johnson 50 model number 50ESL71S. Thanks.

 

[glenn property of pam]

Re: Melted Thermo Switch

best to have the cylinders measures for out of round before decieding or go large then have the machine shop bore to match.

 

[boobie]

Re: Melted Thermo Switch

Did the mtr have a blown head gasket ??

 

[Jeremy T]

Re: Melted Thermo Switch

No the Head Gasket was fine. Just the cylinder has some grooves in it. The Head on that cylinder has a grayish white appearance which makes me think that cylinder was running lean.

 

[Jeremy T]

Re: Melted Thermo Switch

Im having trouble finding any websites that carries pistons and rings for this engine. ********** says the part is obsolete and another site states that part was replaced by another part which is also obsolete. Does anyone have a good company they can recommend I call who carry older engine parts? Thanks.

 

[boobie]

Re: Melted Thermo Switch

Go to the top secret files at the begining of this forum and look for salvage yards.