1964 18 hp Evinrude overheated...

[josh6780]

ok I have a 1964 Evinrude 18hp. It ran great. Only problem was the cooling system was not working right. Long story short I got some bad advice from the dealer and I ended over heating my engine pretty bad. Started to loose power, cut it off and hissing bad. So my first question is how does the cooling system work on these things? Is there a head exhaust relief so I know that the head is actually being cooled? I was only getting a very fine mist out of the lower exhaust relief. I have done everything I know to do. everything in the lower unit is correct.

That being said I understand I probably have done some sever damage already. I did a compression test and the bottom is 90, the top is 60. I am sure that is bad? I don't think they are suppose to be that different. So What I am about to do right now is take off the head and try and figure out why water was not getting to it in the first place. I figure I am probably going to have to replace the rings and bearings anyway.

Need Part numbers for the head gasket and the side outer head gasket? I don't know what that is called. its to the left of the head. Maybe the Exhaust cover? Go ahead and give me part numbers for that rings and bearings also. Should I use aftermarket or go to my dealer? I am mad at my dealer right now

If someone could explain how I know my cooling system is suppose to work and all the places I see water coming out that would be great.

 

[tashasdaddy]

Re: 1964 18 hp Evinrude overheated...

it actually sounds like your tstat is stuck, you are getting mist out the exhaust relief port so the impeller is working. the compression difference, could be a stuck ring due to carbon build up, and a decarb could take care of that. i do not have a 1964 manual, sorry.

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

That's what I thought also! but I took the t stat out. Thats right, my engine overheated with no t stat in it at all.

I know I need a manual. I just don't want to buy one. I am about to spend a bunch of money on parts. I also have one for a 73 model and I figure its not much different.

 

[F_R]

Re: 1964 18 hp Evinrude overheated...

Well for certain, you are going to have to replace the head gasket and exhaust cover gaskets. They are guaranteed to leak if you don't. Once you get those parts off you will be able to see the exhaust (hot) side of the pistons and rings. Chances are you will find scuffed pistons and stuck rings.

The '64 and '68 models are pretty much alike. You can see the '68 parts list at http://shop2.evinrude.com/ext/index.aspx?s1=0efc55faccc15ea323b0e2277f02f075 but don't take the part numbers as gospel because there is a chance they are different for that year. At least you will be able to see what you are getting yourself into.

 

[tmasloske]

Re: 1964 18 hp Evinrude overheated...

I have a 1968 18. The parts manual lists the following:

Cylinder Head gasket - P/N 306163
Thermostat Cap Gasket - P/N 308328
Thermostat seal - P/N 310058
Thermostat - P/N 378065

Hope this helps.

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

Thank you! Can you give me the pistons and rings parts? Do you have a list you could email me?

 

[tashasdaddy]

Re: 1964 18 hp Evinrude overheated...

exchange email addresses thru the PM system.

 

[tmasloske]

Re: 1964 18 hp Evinrude overheated...

Use the link provided by F_R. Shop Evinrude.com has all the parts diagrams for the '68 18.

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

I have a 64 18.

 

[jbjennings]

Re: 1964 18 hp Evinrude overheated...

If it were me I wouldn't buy pistons and rings, period, but definitely not until you know your's is bad. Take off the bypass covers like F-R said and the head so you can take a look inside. You'll also need the head off so you can check it for warpage and replace the gasket. If you don't see anything really bad, then check for warpage, resurface the head if you need to, and reinstall it. Then check your compression. If it's still bad then consider getting a used powerhead. You'd get by cheaper than putting new pistons and rings, I would think.
Just an idea or two,
JBJ

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

ok I got the exhaust plate off. The bottom rings are fine the top not so fine. I think it will be alright though.

here is what I don't understand. first of all. How in the world is my engine not getting cooled. I have checked EVERYTHING. Every tube every water path. I know water has to be getting to the head unless some kind pressure or suction or something draws it away. Cause everything is clear. I don't have a gasket on my t stat cover so I can see water seeping through. So I know its getting to the head. (no t stat is installed at the time)

In the exhaust, So I guess its ok for water to get in the combustion chamber? Cause you can see right through to the rings and pistons. When I turned the engine over to look at the rings I could see water in there.

So what now?

 

[jbjennings]

Re: 1964 18 hp Evinrude overheated...

On the side of the motor that the shifter is on (starboard side), you took off the bypass covers, right? That's were you saw the pistons and rings? That's the intake side of the block, not the exhaust. The other side of the block (port side) has the big exhaust cover. It should be a 2-piece set-up. It has to have good gaskets between the 2 parts of the exhaust cover to keep water out of the cylinders. You should never have water in the cylinders. If you do, it's either a bad head gasket or bad exhaust cover gaskets.
There are a few reasons that your motor might not be getting cooled that I can think of:
1. the exhaust cover gaskets are leaking, letting exhaust gases escape into the water jackets, blocking the flow of water through the water jackets.
How does the water flow out of the exhaust relief look? Is it spitting lots of water out on idle? It should!

2. You may have melted the upper water tube grommet during the overheat and caused it to restrict the flow.

3. Bad water pump impeller, stopped up intake screen/passages, bad pump housing, bad pump insert, etc.

IDEAS: USe some duct tape and 3/8 fuel line to connect your water hose to the water tube that goes to the powerhead (with the lower unit off, of course). Turn the water on, crank the motor and see how it looks coming out of the exhaust relief and how the powerhead feels. If it feels ok and has good flow out the exhaust relief, you know the problem lies in the lower unit somewhere. If not, you at least have an idea that something is wrong up top.

Use a drill to attach to the driveshaft and submerge the lower unit and see how well the drill causes the water pump to push water out the copper tube. If it doesn't pump well you may have a problem with your water pump.

Questions--what did you see wrong about the top piston rings?
Does the motor run now?

Hope you figure it out,
JBJ

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

the top piston was scored on top. The rings looked stuck at that location also. They looked ok all the rest of the way around. There was water in the lower piston cylinder.

I know the lower unit as to be pumbing water to the head cause I can see water seeping through the t-stat cover. (I don't have a gasket on the cover right now and no t-stat is in there)

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

top

 

[CATransplant]

Re: 1964 18 hp Evinrude overheated...

So you took the cylinder head off, right? You said the top of the piston was scored? Do you mean scratched? Beat up? How did the cylinder wall look? I think we may be getting our words scrambled here.

I didn't see, earlier, where you had pulled the cylinder head. If you have, how did the gasket look? How do the cylinders look. You said that the upper piston ring on one didn't look so good. What do you mean? How did it not look good?

Use all the words you want to explain what you're finding, and be sure to tell us what you have done before the step you're describing. It will help us help you.

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

I didn't take off the head gasket. I only took of the exhaust cover and I could see the pistons through the ports. I could only see through the side of the port. The top of the piston looked scored enough that it would stick the rings. Don't know about the cylinder wall. I saw water on the bottom piston while I was turning engine.

Keep in mind this engine ran perfect and started on the second pull from setting for 30 years. Water was misting out of the exhaust. I could not tell if it was getting to the head. So I took off the t stat cover and also took out the t stat itself. put the cover back on, cranked the engine, saw water seeping through the cover just a little bit since there was no gasket. So I know water has to be getting to the head. I also ran water from the top of the head and it ran down just fine through the pee hole. So There are no blockages ANYWHERE that I can tell from me messing with this for days now.

 

[josh6780]

Re: 1964 18 hp Evinrude overheated...

top

 

[jbjennings]

Re: 1964 18 hp Evinrude overheated...

Josh,
You can't run a motor that hasn't run for 30 years without changing the water pump impeller. The rubber in the impeller will get hardened and it just won't work. You can't judge if it's pumping water well enough to prevent overheating by the seepage from the thermostat cover. It does mean some is gettin there obviously, but it sound like in this case, it wasn't enough.

Now to the damage:
I'm no expert and hope someone who is will see and answer your post but here's my opinion.

1. If you can see damage at all just through the bypass covers then most likely you've got some bad gouging on your cylinders and a bad piston at the very least.

2. Judging by your compression numbers (the top one being >30% lower than the bottom), your powerhead is probably toast.

The fix:
Get on ebay or craigslist or aomci.org's free classified section and find yourself a good used powerhead for around 75 or 100 bucks. Install it, put in a new water pump impeller and possibly new lower unit seals if the lower unit leaks water and enjoy your motor. The powerhead on your motor was used with almost no changes for several years and probably darned near all powerheads from '62 to '67 would fit it, possibly even older. (when you find one near your year, post again and someone will tell you if it will fit for sure)

You seem to be leaning toward new pistons and such but I believe after taking the block to a machinist, getting oversized pistons/rings, you'll be out far more dough than a used powerhead.

Once again---- just my opinion,
JBJ

 

[samo_ott]

Re: 1964 18 hp Evinrude overheated...

I would try changing the head gasket. And make sure the head is not warped when it is off. Then fire it up with the thermostat & housing off and see how how the water squirts out the hole. If it does not really come out much, change the impeller, maybe the water pump housing also.

 

[Mas]

Re: 1964 18 hp Evinrude overheated...

Josh,
You can't run a motor that hasn't run for 30 years without changing the water pump impeller. The rubber in the impeller will get hardened and it just won't work.

I agree with JB! Your overheat was likely due to a bad impeller. An impeller with a vane or two will still pump water...but not well enough to prevent an overheat at WTO. Plus, missing vanes will usually end up restricting water flow by clogging up the cooling passages or water tube.

It is recommended to replace the impeller about every three years whether that motor was used or sat...it gets worse if it sits!

Take the head off and see what your cylinders look like...then decide your next course of action.



MAS