New Impeller Melted and Water in Gear Oil?

triscadek209

Petty Officer 3rd Class
Joined
Apr 16, 2014
Messages
82
Finally got out to fill the outdrive up with oil and figured Id fire her up in the drive way for a few minutes to make sure the outdrive install went well. Plugged the hose up to her and off we went. Let it idle for a moment then bumped it up to a fast idle (2500rpm) to get the gears spinning real good to ensure no problems..... theeeeeeeeeen I notice smoke coming from the outdrive, immediately kill the motor. Pull the gear cover off to find it bubbly and cut with water and pulled off the impeller to find it was spinning the aluminum housing and melted the plastic. Thank god the smoke was the impeller plastic and not the gears... my question is, how did this happen? was the impeller starved of water? I had the ear muffs on and the hose about 1/4-1/3 on, was spewing out fairly good... FYI this is a BRAND NEW impeller assembly.

Problem number two, can water get in where the gears in being just off the muffs? Mind you I replaced the oil 5 min bfore I fired her up, granted it was the oil I pulled out of the unit which had only been on/in for 1 hour of lake time and found water in the bellows... the oil looked good which is why I re-used it. Im thinking chances are there was water in the oil and I just couldnt really see it...?

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triscadek209

Petty Officer 3rd Class
Joined
Apr 16, 2014
Messages
82
Re: New Impeller Melted and Water in Gear Oil?

... I think I just answered my own question... water flow from the muffs was too low I think.
 

sam60

Captain
Joined
May 21, 2011
Messages
3,189
Re: New Impeller Melted and Water in Gear Oil?

I know of one guy here who thinks I'm nuts for doing this :cool:, but I made a water inlet adapter to mount upstream of the impeller. It takes little time to access and mount and no more muffs. I keep my impeller stored elsewhere until it's time to boat.

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triscadek209

Petty Officer 3rd Class
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Re: New Impeller Melted and Water in Gear Oil?

Its kinda hard to see how that works as the pics are too small
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: New Impeller Melted and Water in Gear Oil?

What drives are y'all working on here?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,089
Re: New Impeller Melted and Water in Gear Oil?

Looks like a regular Cobra drive.
The one on all 4/6/8's
The water should be turned all the way up.
The oil in the pic right now has about a BILLION bubbles.
That's why it looks like that.
Let it set for a day and look again.
It's possible for the water to get to the upper gear set through the water pump shaft.
But from the looks of the housing/ impeller it didn't get any water at all.
 

triscadek209

Petty Officer 3rd Class
Joined
Apr 16, 2014
Messages
82
Re: New Impeller Melted and Water in Gear Oil?

Drained all the oil, it was definitely milky. I think some water snuck in from the lake trip last week before I drained/saved it. No biggie, $25 I'll go get some more for peace of mind.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,149
Re: New Impeller Melted and Water in Gear Oil?

NEVER run an engine on the muffs at 2500 rpm and your hose should be on 100%. Idle speed only. There is a seal behind the water pump shaft that can leak water into the drive. If you just put new oil in it, and only ran it on the muffs and water got in, it could be that seal.
 

jmz

Cadet
Joined
Dec 4, 2011
Messages
26
Re: New Impeller Melted and Water in Gear Oil?

looks to me like you didn't melt the impeller but probably spun the liner and melted the housing and probably put a hole in it.
 

triscadek209

Petty Officer 3rd Class
Joined
Apr 16, 2014
Messages
82
Re: New Impeller Melted and Water in Gear Oil?

Turns out the pipe in between the upper and lower unit that carries water to the impeller got left off. It stayed on the old upper and stayed on the old lower. Basically I had two out drives and 1 had a good upper and the other had a good lower.
 
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