C85 overheating: "Spooge"

[Tommy in FLL]

I pulled the thermostat cover off of my '96 Yamaha C85 today. This engine runs without a thermostat, due to some internal problem that causes it to overheat. The warning siren goes off if I run the engine at 3000 rpm [planing speed] for more than about one minute.

I live in Fort Lauderdale, and the canal behind my house and all the canals that I normally operate in are "no wake". They are also all filled with brackish water, which is largely salty.

-Last night I was feeling good. I took the boat about a half-mile from my house, cleared the canals of manatees....and then brought it up on plane. I normally never do this, since it is illegal, but I wanted to see what would happen and the sea cows are out in the intercoastal anyway. It ran good for 60 seconds, and I was 200 yards away from the house when the overheat horn came on. I pulled it back to wake speed, shut it down, and 30 seconds later when I fired it up again the horn was off.

Today I pulled the thermostat cover. I removed the cover, removed the pressure regulator and its' spring, and used a screwdriver to remove a bunch of spooge from the engine.

Is there any other word for this stuff?

This stuff is kind of "clear". What is it, and is there a product I can pour down the water channels to burn this stuff out?

THE BIG PROBLEM: A bunch of crud in the cooling passages. But I'm not sure that it is actually a problem~

I pulled the thermostat cover off to test a hypothesis that I've had for a while: the exhaust gaskets are leaking into the cooling jackets. I guess 2-stroke engines run hot enough for their exhaust manifolds to warrant water-cooling. As a result, I have gaskets in question. When I ran the engine with the t-stat cover off, I had more exhaust coming out of it than I had out the exhaust ports! I changed the head gasket in January. I haven't done a compression check, but I suspect it is fine.

The exhaust manifold: I'm worried about pulling all those bolts out, since there are lots of them and some may very well get stuck. Then I'll have to drill them out and helicoil what is left. I fly airplanes for Fedex; with my schedule that will likely result in weeks of delay!

Here's the pix: Thanx for your help!

T

 

[Bradzo]

Re: C85 overheating: "Spooge"

I pulled the thermostat cover off of my '96 Yamaha C85 today. This engine runs without a thermostat, due to some internal problem that causes it to overheat. The warning siren goes off if I run the engine at 3000 rpm [planing speed] for more than about one minute.

I live in Fort Lauderdale, and the canal behind my house and all the canals that I normally operate in are "no wake". They are also all filled with brackish water, which is largely salty.

-Last night I was feeling good. I took the boat about a half-mile from my house, cleared the canals of manatees....and then brought it up on plane. I normally never do this, since it is illegal, but I wanted to see what would happen and the sea cows are out in the intercoastal anyway. It ran good for 60 seconds, and I was 200 yards away from the house when the overheat horn came on. I pulled it back to wake speed, shut it down, and 30 seconds later when I fired it up again the horn was off.

Today I pulled the thermostat cover. I removed the cover, removed the pressure regulator and its' spring, and used a screwdriver to remove a bunch of spooge from the engine.

Is there any other word for this stuff?

This stuff is kind of "clear". What is it, and is there a product I can pour down the water channels to burn this stuff out?

THE BIG PROBLEM: A bunch of crud in the cooling passages. But I'm not sure that it is actually a problem~

I pulled the thermostat cover off to test a hypothesis that I've had for a while: the exhaust gaskets are leaking into the cooling jackets. I guess 2-stroke engines run hot enough for their exhaust manifolds to warrant water-cooling. As a result, I have gaskets in question. When I ran the engine with the t-stat cover off, I had more exhaust coming out of it than I had out the exhaust ports! I changed the head gasket in January. I haven't done a compression check, but I suspect it is fine.

The exhaust manifold: I'm worried about pulling all those bolts out, since there are lots of them and some may very well get stuck. Then I'll have to drill them out and helicoil what is left. I fly airplanes for Fedex; with my schedule that will likely result in weeks of delay!

Here's the pix: Thanx for your help!

T

overheating

 

[Bradzo]

Re: C85 overheating: "Spooge"

Yes you will break almost all of the bolts in the block, and to get to the bottom ones to drill out you have to lift the power head up with host or engine stand. and replace gaskets. from what i understand if the gaskets are leaking it would overheat at idel also. not 100% sure, but i am having overheating problems that i cant resolve.

 

[Tommy in FLL]

Re: C85 overheating: "Spooge"

I know there is some sort of seal gone bad-

I took off the t-stat cover, lowered the motor into the water, and started it up. Immediately there was exhaust coming from the opening.

Me and a friend changed the head gasket right after I bought it in November. I haven't compression-checked it lately, but I suspect the head gasket is fine.

-We had no problems getting the head bolts loose. Some were a little stubborn, but rocking them back and forth made all of them come loose eventually. You don't think the exhaust cover bolts will behave this way?

Thanx in advance!

T

 

[Tommy in FLL]

Re: C85 overheating: "Spooge"

Yes you will break almost all of the bolts in the block, and to get to the bottom ones to drill out you have to lift the power head up with host or engine stand. and replace gaskets. from what i understand if the gaskets are leaking it would overheat at idel also. not 100% sure, but i am having overheating problems that i cant resolve.

Do you have a lot of crud in the cooling passages like in my pictures?

T

 

[pine island fred]

Re: C85 overheating: "Spooge"

What BRADZO said, do not attempt to remove the exhaust cover. Most all the bolts will break off. Is it possible you installed the head gaskets wrong? Kind of baffled on the exhaust coming out the thermostat housing.
Might be time for an engine change. Just bought a 50 2 stroke with carbs for $4400. Dont believe they make the C ( commercial series) anymore. If you eventually get a new motor, flush it after each use.
Ever fly out of RSW ? Use to work there until they quit bringing in the 27s. Good outfit! regards FRED

 

[pine island fred]

Re: C85 overheating: "Spooge"

BRADZO, you said you have an o/heat problem. Did it start after you changed the impeller? Sometimes the stainless steel eccentric cup come un indexed when you put it together. Restricts the pump output. FRED