Low to no water at idle

[cbourbeau32]

I just replaced the impeller on my 18HP 65' model Evinrude. At idle there is little to no water coming from the exhaust port. When I give it some throttle the water flow increases drastically. The flow isn't a stream as I've seen in Youtube videos and on other engines but it is a significant amount of water. Is this normal? I don't think it is. Thanks, Charlie

 

[racerone]

Re: Low to no water at idle

Did you install a factory impeller or aftermarket ?------Did you inspect the aluminum pump housing for wear ?--------In the past I have put these pump housings in a lathe to bring them back to " factory new " dimensions.

 

[cbourbeau32]

Re: Low to no water at idle

The impeller was purchased from Iboats link on this forum. I did forget to look at which way the fins on the impeller were pointing (looking down on it from a top view) when I took it out. I looked at some pictures I found online and installed it that way. Not sure if that mattered or not. I will probably replace the housing and see if that helps.

Thanks, Charlie

 

[Bosunsmate]

Re: Low to no water at idle

I wouldnt bother too much about fin direction, it will sort itself out after one rotation. I normally pull the starter very slow for the first crank after installing( and motors in water) just in case i got it the wrong way around.

 

[boobie]

Re: Low to no water at idle

Have you checked the motor temp with a temp gun??

 

[cbourbeau32]

Re: Low to no water at idle

Thanks Bosunsmate!

@ boobie, I have not checked with a temp gun but after I ran it for a few minutes today it was hot to the touch, not too hot to touch it but fairly hot, not sure if it was overheated.

Thanks, Charlie

 

[cbourbeau32]

Re: Low to no water at idle

I just took the lower unit off and plan to replace the rest of the water pump (I only replaced the impeller) if I remember correctly the housing had a hairline crack in it. Could that have been the problem. After I took the lower unit off I did try to run a piece of weed whacker string up the pipe that the water goes up and then up the pipe where the water comes out and it wouldn't go very far either direction. Would it hurt anything to use my air wand from my air compressor to blow compressed air up either direction to see if I can dislodge any blockage that might be there?

Thanks, Charlie

 

[Mi duckdown]

Re: Low to no water at idle

Was there any part of your of old impeller missing?

 

[kevinwd1]

Re: Low to no water at idle

I recently fixed up the water pump in a 1962 28hp Johnson. I replaced both the impellor and housing and it pumps water at idle no problems .I checked water flow when the lower unit was off by connecting a hose to water tube. Heaps of water flowed though the motor so I was confident that there were no restrictions. This probably wouldn't work if your motor has a thermostat in it, mine doesn’t

 

[cbourbeau32]

Re: Low to no water at idle

@ Duckdown, I don't remember any of the impeller missing.

@ Kevin, I tested this morning with my air compressor and a blow wand that I have which has a rubber tip on it which seals really well against the "up tube" that connects to the water pump housing and when I blew even a small puff of air into it it came out the exhaust with the same force I blew into it with. I think the thing to do is replace the housing and all.

Thanks, Charlie

 

[cbourbeau32]

Re: Low to no water at idle

Ok, I moved the boat over to my water hose and adapted a water balloon filler to fit my up tube and turned on the water. Once the water went up the copper tube and filled up the water channels (not sure what they're called) inside the engine then even the slightest water pressure will push water out of the exhaust which leads me (in my lack of experience) to believe that it must be the water pump housing which had a hairline crack in it (new impeller). Can anyone else think of something else for me to try? This probably has nothing to do with the problem but the copper tube coming down from the engine has some side to side play but that may very well be by design.

Thanks, Charlie