OMC Cobra Water Pump Problems

[havasuboatman]

Re: OMC Cobra Water Pump Problems

Most of the water flows out from the transom and exhaust bellows releaf cuts. It can come out of the prop. It doesn't have to.
If you are using an "ear muff" type hose adapter, the hose isn't forcing the water thru the engine. If there is blockage the water just sprays out from under the cups.
Follow the water inlet hose from where it comes thru the transom assy. The oil coolers are fitted in line and have two smaller oil line sticking out of the side.

 

[airdvr1227]

Re: OMC Cobra Water Pump Problems

You might not actually see water coming out through the rear of the propeller on the hose and muffs. Typically the bellows have drain holes in them before the prop. Pretty sure that as long as you see water exiting the rear of the boat while it's running you're OK.

 

[kevlh21]

Re: OMC Cobra Water Pump Problems

 

[airdvr1227]

Re: OMC Cobra Water Pump Problems

That looks badly beat up. Almost positive parts of that impeller have found new homes downstream.

 

[HT32BSX115]

Re: OMC Cobra Water Pump Problems

Most of the water flows out from the transom and exhaust bellows releaf cuts. It can come out of the prop. It doesn't have to.

Yeah......my 460 King Cobra ran for about 10 years with NO exhaust bellows installed......... No water or exhaust came out the prop!


Looks like you're gonna need a new water pump, housing, etc.....


You need to remove the oil and PS coolers and associated hoses to clear them too....

 

[kevlh21]

Re: OMC Cobra Water Pump Problems

I can't even find the oil cooler/ps cooler

 

[airdvr1227]

Re: OMC Cobra Water Pump Problems

Adults only section when you first come into this section of the forums. Download the correct manual for your rig.

 

[HT32BSX115]

Re: OMC Cobra Water Pump Problems

Look for a hose coming from a gray 1/2-3/4" tube at the transom plate.

That hose is the raw water supply line. It should go to your PS cooler and then to the oil cooler before going to the T-stat housing.

The hose will be connected to #68 below.

 

[Lou C]

Re: OMC Cobra Water Pump Problems

WOW that's about the worst I've ever seen for an impeller...but it doesn't take much if it's run dry...the only time I had to replace mine was the first time I winterized it...running on the hose...it started to run hot...then was OK...then was getting hot again...(never went over 200 though). Anyway the mystery as to why it ran hot...was solved...when I went in the basement and saw the freshly done laundry...yep my wife ran the wash and that dropped the water pressure enough to let the engine run hot. Anyway the impeller had only slight damage...a little cut out of one of the vanes and the cage was shifted a bit. I replace em every year as preventative maintenance and they always look fine...I save the old ones and leave em on the boat because in a pinch I could replace it even with the boat at the dock hanging off the swim platform or anchoring in a shallow spot I could stand in the water and tilt the drive all the way up and replace it...

I'd be looking to inspect the whole cooling system from the water intake hose to the risers...parts of the impeller could be all over....

 

[Gary H NC]

Re: OMC Cobra Water Pump Problems

After looking at that the impeller housing will need replaced also.
Tip:Use a little grease on the new impeller when you install it.Also replace the gasket behind the metal wear plate.

The PS cooler is a round shaped tube.You will see the water hose from the transom going into it.The front end of it should have the hose running to the T-stat housing.

 

[Gary H NC]

Re: OMC Cobra Water Pump Problems

The PS cooler should look similar to this one,

http://cgi.ebay.com/ebaymotors/POWE...6138945QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

 

[HT32BSX115]

Re: OMC Cobra Water Pump Problems

Wow!

Dude wants a LOT of money for it huh?


Maybe I should sell mine!!

 

[Gary H NC]

Re: OMC Cobra Water Pump Problems

Wow!

Dude wants a LOT of money for it huh?


Maybe I should sell mine!!

That was a cheap one! A few were listed for near 200 bucks!

Shine that baby up and throw it on Ebay!

 

[HT32BSX115]

Re: OMC Cobra Water Pump Problems

I am just AMAZED that this stuff can sell for that much money!

The SS braided hoses and the steering actuator is still there too....

I guess I'll do that........It sure ain't doing me any good unless I can use it on my Mercruiser

 

[kevlh21]

Re: OMC Cobra Water Pump Problems

I took out the oil cooler and it looked great. No impeller fragments to be found.

 

[HT32BSX115]

Re: OMC Cobra Water Pump Problems

I amazed that your impeller disintegrated as fully as it did. those pieces were so small!


Sometimes the larger fragments get lodged in the hose and fitting in the gimbal. The plastic fitting (#18 in the pic above) has a smaller diameter than the hose and will sometimes stop some pieces from passing.....


I would be removing the drive and and back-flushing water from the t-stat to the gimbal mount with the drive off so I could observe the flow from that fitting.


ALL the cooling water goes from the raw pump thru that fitting and assoc hoses and coolers before going to the t-stat housing.....

 

[robcurtiss]

Re: OMC Cobra Water Pump Problems

I'd like to piggy-back my issue with this thread. My 'new-to-me' boat has overheating issues...water is NOT being pulled in by the impeller. I have removed the hose at the T-stat housing to confirm this. The impeller was in okay shape, with a crack on only one of the fins, but I replaced all the parts EXCEPT the housing itself, which seems in fine condition. I have flushed the hoses in both directions (from the T-stat to the impeller and from the muffs to the impeller)...no debris came though and good flow to both. I have checked and rechecked my seal of the impeller housing and made sure the drain/relief hole was clear. I now have the outdrive in a water bath to simulate the lake.

The impeller still pulls NO water to the t-stat hose.

HELP, PLEASE! I have looked online and through my Clymer's book with no idea on what to even look for next.

 

[HorizonblueDK]

Re: OMC Cobra Water Pump Problems

A few years ago I repaired a Bayliner with a 351 Ford/Cobra outdrive, that was overheating.
I also replaced impeller, housing, flushed the system, checked everything 2-3 times, but it still overheated. I found out that the water supplied to the thermostat housing was filled with bubbles, and the flow/volume was very low.

Finally I decided to take the drive apart and discovered that there was a hole(corrosion) in the suction tube, that feeds the pump.

#79 on the drawing

This tube is placed in the exhaust channel, so when the pump(and engine) is running, this tube is mostly surrounded by exhaust gas, which is then sucked through the hole and disturbs the pumping process.

After replacing the tube, it pumped like never before.

 

[Don S]

Re: OMC Cobra Water Pump Problems

You need to start a new thread with your problem, not "Piggy back" onto someone elses post.