cooling 1999 6hp evinrude 4 stroke

[Michawilden]

Yesterday I had some time to tinker with the motor. I did not bring a drill but I had a garden hose that I could attach to the copper tubing with the Lower unit removed. I attached the photo's. As you can see a lot of water shoots out at the exhaust at the back of the midsection. And only a small stream at the tell tale. This should not be like this right? I have never see it like this.

If I remove the thermostat cover, only a very small amount of water comes up to this part of the powerhead. It is defenitively not a stream.

 

[Crosbyman]

any chance you can just pull the intake manifiold to inspect water passages because by the looks of the part water circulates around it and feeds a supply to the thermostat
the water supply to the thermostat seems weak compare to the rest

just a suggestion mind you because little info seems available on waterflow paths in a 6hp 4 stroke. ph.

 

[Michawilden]

Yess, I can do that. There is an exhaust tube going down from that manifold. I hope that that comes loose also when I remove the intake manifold. And I hope to see if I can look inside the exhaust leg to see the copper tubing.

 

[Michawilden]

I managed to remove the exhaust tube from the engine without removing the intake manifold.

I didn't see any cracks or something that might be off. Cooling water flows around the exhaust pipe to the intake manifold. In img 5021 it is the centered hole in the plate where the water should come out. I removed the plate and could see the copper tubing. However, this was not alligned at all. The copper tubing in the midsection was off by 1/2 inch towards the front. On the underside of the plate I could see that the copper pipe made an indent in the rubber gasket. With this misallignment, the water flows in the chamber and out of the exhaust port. I could bend the water tube to allign again with the plate and water came out the correct hole. This is with the garden hose slightly open.
With the daylight going away I couldn't test with the Lower unit on but finally a breakthrough. But how this missallignment happened? Might be that pulling the lower unit with the water tube sticking in the impeller housing might pull it out of the hole or something?
How this missalignm

 

[Crosbyman]

With this misallignment, the water flows in the chamber and out of the exhaust port.

pictures are a bit fuzzy ... any chance this is design intent to send a % of water down the exhaust route to provide cooling. you can better orient the tubing you suspect is misaligned but keep an eye on any after effects .

picture 5824 shows the indent (crushed) but would water actually escape the cavity surrounded by a gasket ??

Stange because this is a 24 year old engine.... yet the problem seems recent .

 

[Michawilden]

Well, I dont think it is designed to let a % go into the chamber.
the chamber is open on the back ( it is the exhaust relief). I think the water should not end in this chamber but only up the intake.
The chamber is connected to a passage way on the side of the leg. I can see carbon so exhaust fumes defenitively come pass this. Sometime after christmas I will start her up and see if she cools now.
The tell tale takes the water just above the plate from the exhaust pipe ( nr 21) It goes to the floatbowl and back and then exits the motor.

I think that with pulling the lower unit the copper tubing got pulled and miss alligned. Or a previous owner pulled on it or something. But I seem to remember that the first time I put the garden hose on the motor I didnt have the water flowing out of the exhaust port on the back.

I am looking forward to finishing this motor because it has realy been a PITA and It could still be that the cooling is bad

 

[Crosbyman]

patience brings joy... just realign it and hopefully all will be fine.

 

[Michawilden]

Here we finally had some beter / warmer days so that I could test the engine.
I finally got a steady stream out of the thermostat housing. And a really strong stream at the exhaust pipe. From there it flows to the float bowl and than back to the pee hole. The pee hole is not that strong so I think it might be clogged somewhere.

Why is the ( cold ) water streaming to the float bowl and than to the pee hole? From the drawings it looks like it cools the accelerator pump?
But the important thing is that it cools now. Thanks crosbyman for all the help

 

[Crosbyman]

thanks for your feedback on the problem. Glad you got it cooling but it does remain a mistery doesn't it.


told you.. patience brings joy !