OMC cobra I/O 4.3 6 cyl. impeller isn't sucking water

[derekjoelrust]

With the muffs on, the water won't go up into the outdrive like it always has. Engine running while I pushed the muffs against the outdrive- no luck- it just shoots out from under the muffs. Pulled the impeller out and it was in fine shape- but dry. Is it dry because it's not getting water to it, or had it dried before I could get it off due to the heat it had generated? I have mucked it up in sand and mud this past season. Could the plumbing be clogged between the inlet holes and the impeller? Disconnected the tube that connects to the impeller and blew down through it- and it was difficult. If I had to breathe through it, I would suffocate. Should air flow more freely through that tube?

I kept a CLOSE eye on the temp and did not run the engine long enough to overheat- probably 1-2 minute intervals.

Also, under the impeller, the water chute on the left (port side) was full of water and the chute on the right (starboard) was dry. With a hose, I tried to push water down the port side and it wound't flow through. It did flow down the starboard side and out the inlet holes at the bottom of the outdrive. Is this significant?

Replaced the impeller three years ago, was a bit shredded and not sure if those pieces found their way into the cooling system. I don't think so, because the boat has since run great- not overheating, no problems for the three years since.

- What should I attack first to fix the water flow / cooling problem?
- I already anti-freezed it and was unable to fog the engine (I didn't want to run it while it was unable to cool itself). Now I don't want to fire it up again to fog the engine- is there a way to protect the cylinders (fog it) while the engine is not running?

 

[zbnutcase]

Re: OMC cobra I/O 4.3 6 cyl. impeller isn't sucking water

Sounds like you need a new impeller and possibly new cup and housing. You can fog engine by removing spark plugs and spraying fogging oil in cylinders, replace plugs then crank engine over with coil grounded to distribute oil in cyls. 'nutcase

 

[derekjoelrust]

Re: OMC cobra I/O 4.3 6 cyl. impeller isn't sucking water

Thanks! That helps with fogging. Why a new impeller? The one I'm using doesn't' appear to be bad. Isn't the problem a clog in the line somewhere?

 

[ErieRon]

Re: OMC cobra I/O 4.3 6 cyl. impeller isn't sucking water

If your impeller is three years old, replace it. Not to mention that you ran it without any water flow. That's like taking a shower and putting your dirty underwear back on. If it has developed a memory (fins bent to one side) then it should be replaced. For the money, you really want it to be running as efficiently as possible.