evinrude cooling help please!

[Mr.LS6]

Can someone explain the cooling system on a 89 xp200??

Here is what I have...new pump and impeller, and still no flow at the tell-tale.
I bought boat as an unknown, fairly cheap. The only thing I really knew is that the engine ran. I got it home and put it on the hose, and it does run good, but I have no water at the telltale. So I figured it needed a pump/impeller. I put it all back together, making sure that the tube went into the pump like it should. Fired it up on the hose, and still no telltale. Decided to take t-stat covers off. Found metal tube assemblies laying in each head, with the springs. Plastic melted into the diaphrams. Left off t=stat covers and fired up on the hose. Got what I thought was a bunch of exhaust out of the covers, and after about 30-45 seconds got some water out of holes. Wasn't gushing, just kinda spitting out of the holes in the heads. So I cleaned out melted plastic, and reassembled with only the diaphrams in the covers. Fired it up again. Got a few drips out of the telltale after about a minute. Someone has removed the valve on the side of the motor for the power boost cooling.
Can someone tell me what to check next?? I will get some thermostats this week and have them ready to go. Surely someone knows how this system is supposed to work, I have an OEM manual and it is VERY vague.
Thanks,

Dave

[gfinch]

LOOPER. The water flows from pump thru pipe to exaust adaptor and into the center cavity which has the exaust runners in it. This is the same cavity that the rectifier is located in at the top of the block. Once water is in the block it passes thru drilled holes to the water jacket around the bank of cylinders. To the top of the block thru the thermostat down thru the head , back to the block then exaust adaptor around the inner liner out the prop shaft opening.

[H2OPERF]

The above is correct.The telltale comes from the top of the block,the block will not fill up with water completely idling with the thermostats/housings removed so u will not get good flow from the telltale.The thermostat plastic housings act as valves that cover the holes in the top of the head,when idling the valves are pushed shut by water pressure on the top side of the diaphragm from the water valve on the throttle arm,if its missing nothing is there to keep them closed.You should have good flow with the covers off when runnin on the hose if u have a good water supply.Dave

[Mr.LS6]

Thanks for the description. Now I have a couple more questions.
1. How long should it take to get water at the t-stat covers with them off and engine idling?
2. If the engine had the boost valve installed, how long would it take for water to come out of the telltale?
3. How much, if any, exhaust should come out of the t-stat covers when they're off??
Thanks again!

[BenKeith]

If the valve on the side of the block controlled by the throttle linkage has been removed, it should have the plastic plastic, bullet shaped thermostats used in the 89 looper but it's suppose to have covers and diaphrams replaced with the T-stat covers and springs from the 1992, 70 hp, (these don't have hose fittings in them). The P-tube should be coming from a plastick elbow on the upper port side of the block.

It sounds like you have something someone didn't really know what they were doing tried to rig. I would first make sure the rubber seat in the bottom of both heads are still in good shape, if not replace them. Then I would get two new T-Stats for the 89 motor looper, and the two covers, two springs and two gaskets for the 92, 70 hp motor if that's not what you have. If you don't have the plastic elbow on the port side, get one and run your P-Tube off that. I ran a 3/8" tube and put a 1/8" restrictor in the end.

I've never started mine without the covers on, don't know if they would let exhaust come out them or not.

[gfinch]

Thanks for the description. Now I have a couple more questions.

First.Take everything said by me with a grain of salt.:D

1. How long should it take to get water at the t-stat covers with them off and engine idling?

How high is the sky.:rolleyes: OK. How much water are you forcing into the muff's. More pressure and engine speed = how soon it will fill. All I can say is turn it up. Spin it up. Water should be shooting out of the muff's. WAG 1min.+


2. If the engine had the boost valve installed, how long would it take for water to come out of the telltale?


Not the answer butt. The boost valve puts pressure on the back side of the thermostat which holds the thermostat in the head so it forces the water thru the t'stat, restricting the flow thru the engine. Purpose: keeps heat in to better atomize fuel when you do take off. Also it keeps the block hot and expanded so on acceleration the pistons don't expand and stick in a cold contracted block=cold seaze WAG same as long as the t'stats are seated the same amount of time.

3. How much, if any, exhaust should come out of the t-stat covers when they're off??

If the water isn't going back down the passage to the exaust adaptor to block it , as much as wants to as there isn't anything(water) to stop it.

Thanks again!

Your entirely welcome.:)

[lokinutz]

BK...
Just to confirm, when you change to the 70 hp tstat covers and springs, you remove the old diaphragms and just run the black plastic t stat holders with t stats in them, and the new springs take place of the diaphragms. Then the only water coming out the back of the motor is the one hose from the top of the exhaust area, and the water is now circulating past the t stat back into the head, down through the motor/out the mid?

[gfinch]

Crap just had an earth quake.

[BenKeith]

Yes, that's the way it works

Hose keeps the air bled out of the exhuast chest and T-Stats control the temp in the block like any normal T-stat would.