40 hp thermostat on big twin

[denislajoie]

i have a 40 hp johnson manual shift engine, it was overheating so i took out the thermostat. i have 2 1967 parts motors also 40 hp but with electric shift, i decided to take these apart as well but they had no thermostat under the cover, do people take them out, what are the consequences to running with no thermostat

 

[tashasdaddy]

Re: 40 hp thermostat on big twin

building up carbon, poor performance, if they weren't need they wouldn't have been put in. the engine was designed to operate and a given temperature.

 

[Paul Moir]

Re: 40 hp thermostat on big twin

Doesn't answer your question, but did you service the water pump (new impeller, wear plate min)? Like all outboards, it needs to be done every few seasons.

Removing the thermostat is treating the symptoms. Keep treating symptoms and you'll end up with a dead patient. Didn't stop people from pulling them though since it "fixed" the outboard.

 

[denislajoie]

Re: 40 hp thermostat on big twin

yep the impeller is good and everythjing else i believe it is you Paul that explained to me how the water goes through the engine and to try running the engine with the thermostat cover off and watrer should gush out. i was just curious to know why the other 2 engines i had were missing. are trhey supposed to be in the same place under the cover witrh the 3 screws on the 2 engines, my good one is approx 1959 and my parts are 1967.

 

[Paul Moir]

Re: 40 hp thermostat on big twin

Yes, just the same. They ought to have them. Probably a temporary fix for an engine someone didn't want to spend money on, or some repair guy who thought that made them better. I don't know why they don't go pull the thermostat out of their cars too.

'60 was the first year for a 40hp, '59 would be a 35hp.