Replacing Thermostats on 1979 Evinrude 115hp

[NAT1VE]

Well today I changed out the Thermostats on my 79' Rude 115hp. I hope this helps others who need to replace theirs somewhere down the line. I tried my best to document as much as possible, but I was Han Solo today. If you can get another person it definitely will help a lot when you need to assemble the housing. one person to push on the housing and the other to thread the center bolt. Here it goes..

I did this with engine off the boat on the stand. unlock the hood, remove. Now head to the backside of the engine.

Next grab yourself a can of PB blast, DeepCreep or WD40. This is some stuff I had, but anything will help.

Disconnect hoses and Tell-tale. Not a must but a good time to inspect it for any blockage, mine was completely plugged.

Careful backing the housing out, the springs could go flying.

Inspect the passage ways for any blockage as well.

Now disassemble the housing, Remove old thermostats gasket material, o-rings and cork o-rings. Using razor blades or gasket scraper. My cork o-rings were completely deteriorated, they must have gone quite sometime ago..:blue: upon re-assembling the larger holes on the center housing face upwards!

I had to fast forward a little, but Assembly is just the reverse. I used Blue RTV to help the gaskets stick together as well used it on the engine block. Because I was alone I found that using small zip-ties to relieve some tension off the springs helped quite a bit. I clipped them with wire cutters right before I started threading the center bolt. Be sure to place the 2 end bolts in the housing before you tighten the housing to the block too. Tighten all the bolts and replace the hoses with fresh ones, I like to run a clear hose on the tell tale. Congratulations, the Thermostats are changed, and your engine is now much happier!

New Thermostats installed and no parts left on the bench, except old ones. Hope this helps! Cheers.

 

[Bosunsmate]

good job, you may like to read this one on the telltale, it should at least wrap over the block, but its best to come off the top of the heads
http://forums.iboats.com/forum/engi...aq/228380-johnson-evinrude-adding-a-tell-tale

 

[NAT1VE]

good job, you may like to read this one on the telltale, it should at least wrap over the block, but its best to come off the top of the heads
http://forums.iboats.com/forum/engi...aq/228380-johnson-evinrude-adding-a-tell-tale

Thank you! This is great, I will be doing this today. So much information here along with "Tips n' Tricks". I will be sure to add a picture of this after I am finished. Thanks again for the heads up. :thumb:

 

[1983 ercoa 21']

Very nice and detailed job !

 

[Ilovefishing]

Im guessing this is similar to the set up on my 78 Johnson 85 V4 engine. If so this helps A LOT!!!!! thanks

 

[emdsapmgr]

One thing to add to your procedure. There are two pinholes in the plastic valve body on your year model. You need to visually check them to be sure they are both clear prior to re-assembly. On this model, the holes are failry small and can accumulate debris. If one of those holes plugs, that side of the block will overheat-even with new stats. Those holes permit warmed/heated water to get to the back of the stats to tell them to open.

 

[NAT1VE]

One thing to add to your procedure. There are two pinholes in the plastic valve body on your year model. You need to visually check them to be sure they are both clear prior to re-assembly. On this model, the holes are failry small and can accumulate debris. If one of those holes plugs, that side of the block will overheat-even with new stats. Those holes permit warmed/heated water to get to the back of the stats to tell them to open.

Yes very true, I failed to mention that. I guess I spaced it when I said that the larger holes on the valve body face upwards. Thanks!

ILoveFishing Looks to be close in procedure, when I glanced at the parts diagram for your model.

 

[NAT1VE]

good job, you may like to read this one on the telltale, it should at least wrap over the block, but its best to come off the top of the heads
http://forums.iboats.com/forum/engi...aq/228380-johnson-evinrude-adding-a-tell-tale

After BosunMate recommended a great piece of information, I decided I would Add this to the tutorial.:thumb:

A quick bit of information the above link provides, is that. On most Evinrude/Johnson motors(early models). "Many of the early systems tapped into the water jacket at low point, and ran the outlet hose straight down to the bulkhead fitting. This configuration can cause air bubbles to enter the water jacket and cause hot-spots." Which should then be re-routed up and over the engine block to prevent air from entering the system.

Cost of this Mod is less than $10 and 15 minutes of your time.

List of Materials.

-1/8 fitting w/ barbed end(if you break yours like I did) :facepalm:
-Clear tube 5/16"
-Teflon Tape

Before Picture, stolen from the above link for Reference.

Starting out find the tell tale fitting attached to the back of the engine block.I used a crescent wrench to remove mine. CAREFUL of the barbed end if your engine is old. My fitting was so brittle, a light tug of the hose broke it Off.

Use needle nose pliers to squeeze the fitting attached to the engine base and push down.

Once you have it all removed, grab the clear tube and run it onto the Tell-tale fitting. I used a lighter to warm up the end of the tube, made it easier to slide on. Doing this will make it much easier for you to attach to the housing fitting.

Run the hose up the the Telltale hole and up-over the engine block.

Now install the Hose to the fitting, cut to length and you're done! Continue if either you replaced with a new fitting, or like me broke yours.:lol:

Continued....

Next grab your teflon tape and apply it to the new fitting.

Installed new fitting. I did not use a 90*, because I already had this one on hand.

Install the hose and Voila`

 

[emdsapmgr]

A nice, neat telltale installation.