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mercury 7.5 hp pumping water and steam out pee tube

M

mamarat

New member
I done replace the water pump impeller made sure that the tube is sealing good. I took the lower unit back off and put a drill on it to make sure the pump was working and it pumped a good steam out the top of the water pump tube. it pumps but it not pumping like it suppose to It's spiting water and steam out and the water get really hot. I am running it in a 55 gal. drum. any help would be appreciated .
 
Take the engine / powerhead off.------Replace the melted plastic washer at the top of the water tube.----Factory replacement is a better material.
 
Put the engine in forward gear an see it starts pumping fine. The standard 3 blade prop the comes with the 7.5 has a very short exhaust hub that allows the exhaust gases from the prop to be sucked right into the water inlet above when in neutral in a test tank and causes intermittent cooling and engine getting hot. I have one that does the same thing if left in neutral for extended periods.
 
racerone said:
Nope -----In gear should make no difference.-----It should pump fine in neutral.
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I appreciate what your saying, but I have proven it with a laser temp sensor and watched the engine cool by 20 degrees just by putting in gear and scavenging the exhaust gases away from the intake area. If you put the longer hub prop from a 9.8 it doesn't run hot.
 
I agree, I just want to see if it works for him. I have one that does the same thing even after a new waterpump and new watertube grommet upstairs.
 
I think I might have found the problem. at sometime someone took the water jacket cover off and tried to but it back together with the old gaskets and way to much silicone and had a couple of the holes almost stopped up. cleaned it up and order new gaskets. it might be a week are so before I can get it back together.
I just want to say thanks for all the help..
 
OK, I thought I found the problem but it's still not pumping like it needs to. let me tell you all I done. replace the water jacket gaskets, base gaskets and round gasket on top of the water tube and rubber seals under the power head. If I let it idle it will pump fairly good but when I give it a little gas it start spitting water and not a steady stream. It will do this in gear too. I 'am running it in a 55 gal drum.. Just want to say thanks for all the help already.
 
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