www.iFourWinns.com

The OMC shop manual says to use gear oil like what you use in the outdrive, but if you don't want to use that you can use dish soap, the idea is to lubricate it a bit till the water gets sucked up.
You hook up the muffs, turn on the water and just start it up, you should see exhaust water a few seconds after you start it.
After I start it and see that water is coming out, then I look at the impeller housing (I leave the top cover off) and make sure no water is leaking around the gasket. Because if water leaks out, then air can get sucked in when the boat is on plane and the upper gear housing is out of the water.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Great! Thanks! this afternoon i SHOULD get the part. May I say, these impellers are NOT an easy part to come by.

I'm not sure I have extra outdrive oil, so will use either the soap idea or if the kit comes with lube, i will use it. I think I understand the concept though. I really appreciate the tip about watching for water out of the case, would hate to burn this new one up.

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

Part came in, guess what, not the right one AGAIN! next try wont be here til next week.

I have been told the King Cobra outdrive is the White Elephant of White Elephants...

Man... anyone want to buy a boat????

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

Good lord what a mission I hope you get the right part figured out.

ah HA!! got the right part, installed it in 5 mins! had water flow and cool temps! Life was soo good, then I found the under lying problem.

I must have sucked some muck into my outdrive. The water is only flowing to the bellow. It is not coming out the prop like it is supposed to.

Does anyone have any suggestions on how to flush the outdrive?

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

Are you sure it is supposed to come out the prop when on muffs? I think I remember my SX flowing water only out of the bellows.

There may be nothing else wrong.

Greg

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2008 210SS 6.2L DTS Bravo 1 Now featuring MercMonitor w/SmartTow

I have never seen that style OMC Cobra but on mine its the same as an Volvo SX, most if not all the cooling water at idle comes out of the area under the transom mount.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Hmmm... I know I have a blockage someplace. pressure seems to be building Here is what Happened.

When at idle, temp is good, no major issues. When I bring it up to cruise power, pressure builds, to the extent that it pop's off a cooling hose from the engine. The only thing I can think of is When I was taking the boat off the trailer, and the outdrive was up, but under water, I sucked something in and its blocking? just not sure where or how to find it.? I guessed it was in the outdrive but am not completely sure.

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

Pops off a cooling hose? How is this possible? Each connection is barbed and the hose should have a hose clamp. Theoretically pressure would burst the hose before it "popped off". Guess it is possible to break a clamp, but that situation is highly unlikely.

The pressure SHOULD build when you bring it up to cruise. Faster engine RPMs = faster turning of the crank = faster spinning of the impeller = greater volume of fluid flowing through the same diameter hose = more pressure.

(I know increased velocity screws with the simplicity of this statement, but lets ignore that for the time being)

Do you have a picture or description of what hose pops off? Was it secured properly? My first guess would be that nothing is actually wrong and that you are just missing a (or several) hose clamp(s).

If you are intent on trying to figure out blockage the first place to start would be your thermostat housing.

BTW - water should not come out of the propeller on ANY outdrive to the best of my knowledge. The prop shaft is lubricated by oil and water would be a bad addition to that equation.

I'm not sure how to post photos here but will try and figure out how.

I know, I'm at a loss on how and why the hoses pop. All I know is the have never done it before and now they are. I don't know what else would cause such a thing to happen. Clamps were all on tight, if it is blocked, I do not want to cause additional damage. Now just working on figuring what is going on.

New impeller seems to be working well, but what would cause pressure to build to an extent to pop the main cooling hoses on the front of the engine off the thermostat housing?

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

To post pictures upload the photo to an account like photobucket, and use the IMG links to copy and paste it in the forum.

You have a lot of pressure building in order for that to happen, I'd check the thermo housing first, take it off and rod out all the passages in it, and test the thermostat to make sure it opens at 160 or so. You might even find old impeller parts wedged in one of the thermo passages. If you still have the same problem, check the risers and manifolds, if they clog this is possible, but they'd be getting really hot as well. These open (raw water cooled)systems by design do not build up a lot of pressure, they are dependent on smooth and rapid coolant flow to keep the engine and exhaust from overheating.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Thanks for the tip on how to load pictures. I will go to the boat tomorrow and take some and try and post them! I know that will help a lot.

My Temperature was running really pretty good, 140-150 when all is connected. I know I have a plug someplace, just not sure where to start. does anyone know where to get a diagram of the cooling system flow? that would be very helpful!

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94 258 Vista
5.8 OMC Cobra EFI/V8 OMC Cobra outdrive.

http://www.crowleymarine.com
Look in parts catalog or parts diagram section, and put in your year, engine model # etc.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

+1

When was the last change of the risers? There is really no other location that would block water from leaving the engine besides the exhaust manifolds/risers and the thermostat housing. These items can be removed and checked with a garden hose.

It is not the lower unit: Any blockage in your lower unit would prevent enough water from entering...therefore would lower the pressure, not cause high pressure.

All water pumped into the engine must flow out through the exhaust manifolds/risers. This is true weather the thermostat is open or closed. The thermostat only controls how much cold water goes into the engine (and allows hotter water to go to the manifolds). Cold or hot...all the water exits through the manifolds/risers, and if they are causing that high a pressure build up, then it is time to change them. Hint: you should be able to squeeze the big 2" water hose even when the engine is running. It can be a little firm, but if it is very firm then the water flow is too restricted.

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings