1979 evinrude 35hp issues...need help

[jekuehl]

With my 1979 evinrude 35hp, the thermostat is stuck open so I need to replace it, not sure when the carb was cleaned last so I want to do that (already bought a carb kit), and compression is a little low so I am thinking of using seafoam. Compression is 100 on both cylinders.
-Replace thermostat
-rebuild/clean carb
-seafoam to increase compression

What is the order I should do these three things?

Note: It runs pretty good, I use it every week. Even though the thermostat is stuck open, it hasn't impacting the operation at all. But i know it has long term bad effects. I think the slow speed could be adjusted because I think it runs a little rich. When I look at the plugs, they seem a little wet/fouled. I just want to do some preventive maintenance before I get stuck out in the open water.

 

[oldcatamount]

Re: 1979 evinrude 35hp issues...need help

Replacing the thermostat will allow the motor to run at the correct temp which will help the other issues.

 

[jasper60103]

Re: 1979 evinrude 35hp issues...need help

Also, a new water pump and fresh gear lube is good preventive maintenance if you don't know when done last. Happy boating.

 

[bonz_d]

Re: 1979 evinrude 35hp issues...need help

Order; repair thermostat, rebuild waterpump, change lower unit oil, Seafoam it. Run it.

If you are not having starting issues or other carb related indications then I would leave that carb alone. They are vewry simple carbs and if there was a problem you'd know it! Instaid I would look over all the fuel lines and check for cracking, brittleness or loose fittings. Save that carb kit for when you need it.

Your compression isn't that bad/low but more importantly it is even between the 2 cylinders. Using another compression gage could also give you a whole different set of numbers. So again I wouldn't be too concerned by those numbers.

 

[jekuehl]

Re: 1979 evinrude 35hp issues...need help

Order; repair thermostat, rebuild waterpump, change lower unit oil, Seafoam it. Run it.

If you are not having starting issues or other carb related indications then I would leave that carb alone. They are vewry simple carbs and if there was a problem you'd know it! Instaid I would look over all the fuel lines and check for cracking, brittleness or loose fittings. Save that carb kit for when you need it.

Your compression isn't that bad/low but more importantly it is even between the 2 cylinders. Using another compression gage could also give you a whole different set of numbers. So again I wouldn't be too concerned by those numbers.

Roger that, thanks. I already replaced water pump kit and changed lower unit oil. Ok, I will hold off on the carb kit for now.
I started another thread with pics for the thermostat. I have some other specific questions with that but I posted it under that thread.
http://forums.iboats.com/johnson-ev...ace-thermostat-1979-evinrude-35hp-607209.html

 

[bonz_d]

Re: 1979 evinrude 35hp issues...need help

Wise choice. Again those carbs are very simple and if kept clean they just keep working.
You may concider really looking at all the fuel lines and replace them if you are uncertain as to how old they are. E-gas and old fuel lines don't play well together. Look for the ethanol resistant fuel line.

 

[jekuehl]

Re: 1979 evinrude 35hp issues...need help

Wise choice. Again those carbs are very simple and if kept clean they just keep working.
You may concider really looking at all the fuel lines and replace them if you are uncertain as to how old they are. E-gas and old fuel lines don't play well together. Look for the ethanol resistant fuel line.

Ok, thanks, good point. I will probaly replace those when I am replacing the thermostat. Thanks again. This site is awesome!