Evinrude 85 hp 1974 thermostat question

[SouthernDawg]

Recently purchased a 1974 evinrude 85 hp. Was able to get it running but noticed that no water was coming out of the back holes of the motor. I ordered a new impeller kit but was wondering if a bad thermostat also could cause the motor to not be able to let water out the discharge? Are they (thermostats) hard to change on this type engine? I plan to replace the thermostat also Thanks.

 

[seahorse5]

Re: Evinrude 85 hp 1974 thermostat question

That engine does not have a water tell-tale like the later models do.

At cruising speed and higher, you may see some water exit the exhaust relief holes.

 

[emdsapmgr]

Re: Evinrude 85 hp 1974 thermostat question

That engine has the early cooling system on it. (prior to 1978) Only single thermostat-called a vernatherm. You won't see much water exiting those two exhaust relief ports at the top of the midsection. Here's what you will see: start the engine when it's cold. Hold your hand back by those two ports. After the engine runs for maybe a minute or so, water droplets will start to form on the palm of your hand. That indicates the vernatherm has just opened. That's normal-all the water you will see out of those ports.

 

[SouthernDawg]

Re: Evinrude 85 hp 1974 thermostat question

That engine has the early cooling system on it. (prior to 1978) Only single thermostat-called a vernatherm. You won't see much water exiting those two exhaust relief ports at the top of the midsection. Here's what you will see: start the engine when it's cold. Hold your hand back by those two ports. After the engine runs for maybe a minute or so, water droplets will start to form on the palm of your hand. That indicates the vernatherm has just opened. That's normal-all the water you will see out of those ports.

Great info ...thanks! I'm glad I asked before replacing the impeller and still not seeing a stream of water out the rear of the engine. I never would have guessed. Y'all saved me a lot of grief.

 

[SouthernDawg]

Re: Evinrude 85 hp 1974 thermostat question

That engine has the early cooling system on it. (prior to 1978) Only single thermostat-called a vernatherm. You won't see much water exiting those two exhaust relief ports at the top of the midsection. Here's what you will see: start the engine when it's cold. Hold your hand back by those two ports. After the engine runs for maybe a minute or so, water droplets will start to form on the palm of your hand. That indicates the vernatherm has just opened. That's normal-all the water you will see out of those ports.

Thanks... can you tell me where the vernatherm is located... I've got a manual on the way but patience is not one of my virtues.. thanks my friend
SouthernDawg

 

[emdsapmgr]

Re: Evinrude 85 hp 1974 thermostat question

You can look at the factory exploded parts diagrams at this website: epc.brp.com You'll find the vernatherm/thermostat on the exhaust housing diagram.