Cobra sucking air-

[jajin2004]

1988 5.7 liter omc, cobra leg. After putting on a clear hose from oil cooler to thermostat housing, the hose runs pretty clear (very few bubbles at idle) but then really has air in the hose at 1/2 throttle and WOT and it runs hot. What is the most likely cause? I am taking the outdrive off this weekend and will replace the o-rings on the water tube and also check and replace the inner water tube- anything else? thanks

 

[Gary H NC]

Re: Cobra sucking air-

Have you checked the impeller? You don't need to pull the drive for that.

 

[danond]

Re: Cobra sucking air-

Replace o-rings in the water tube...why? Does it leak? If it doesn't leak, that's not your problem.

I agree with the previous poster. Your impeller is shot. When was the last time it was replaced? Have you *ever* run the engine without a water supply?

 

[jajin2004]

Re: Cobra sucking air-

Just found out that my "mechanic" ran it without water when he winterized it. He said he took off the water pump to do it. I replaced it with one I had and when looking at the one that I took off, there was melted stuff on the metal basket, but all fins were there. So, my concern is that the rubber grommets/seals for the inner water tube are cooked and it is sucking air from there. What do you think?

 

[Gary H NC]

Re: Cobra sucking air-

Running the impeller dry should not affect the water pick up hose...its just full of air and not water.
If the impeller was that hot i would replace it with the full kit including the housing.
I would not use that guy again for any work.