Lower unit leak

Ranger09

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Aug 29, 2023
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Hey folks I finally got around to pulling my boat home to change my lower unit oil and do a pressure test on my prop seals to see where a small leak was coming from. I just got up and made this video to show what I found this morning.

 

99yam40

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Hey folks I finally got around to pulling my boat home to change my lower unit oil and do a pressure test on my prop seals to see where a small leak was coming from. I just got up and made this video to show what I found this morning.

did you smell it to see if it was lower unit lube or oil from the power head?
 

Ranger09

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Aug 29, 2023
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No and not sure I would know the difference. What steps should I take next or look into?
 

99yam40

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remove the drain screw from the lower unit to check for water , get a little on your finger, and smell the lube while you are doing that.
then smell the oil for the power head.
 

KJM

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Jul 31, 2016
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You will need to take off the lower unit to see where the oil is coming from. Any oil leaking like that is too much. I wouldn't put her back in the water until its fixed. First boat I bought had a pool of what I thought was spilled coffee under the leg and I was too naive to even check.....it wasn't coffee. All the seals were leaking like sieves!
 

Ranger09

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Aug 29, 2023
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I just got back this morning and the bottom screw was behind the water inlet. It was definitely leaking oil from there. I trimmed the motor all the way up and wiped everything down real well. Gonna check back this afternoon and hopefully get a good idea exactly where it is leaking. I couldn't tell by smelling what type of oil was leaking from the top part of lower unit. Just wasn't enough to get a good idea. May be able to tell this afternoon.
 

Ranger09

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You will need to take off the lower unit to see where the oil is coming from. Any oil leaking like that is too much. I wouldn't put her back in the water until its fixed. First boat I bought had a pool of what I thought was spilled coffee under the leg and I was too naive to even check.....it wasn't coffee. All the seals were leaking like sieves!
I am really hoping I don't have to do that. I watched some videos last night and it looks like a pain in the butt. I was very surprised to see there was not a gasket for the lower unit.
 

99yam40

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the drain a vent screws have gaskets that should be replaced.
and then retighten the screws after running the motor on the water just to be sure they are still tight. the gaskets crush down and will leak some times after putting new ones on.
 

Ranger09

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Aug 29, 2023
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Just got back this afternoon and the video shows what I found. I lowered the motor and gonna check again in the morning.

 

Ranger09

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Aug 29, 2023
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I am really hoping I don't have to do that. I watched some videos last night and it looks like a pain in the butt. I was very surprised to see there was not a gasket for the lower unit.
Before you took your lower unit off could you tell if it was leaking from where your lower unit comes apart?
 

KJM

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Before you took your lower unit off could you tell if it was leaking from where your lower unit comes apart?
Not really, but it was probably leaking from multiple places, it was an old motor. First drain your lower unit oil and see if its clear or milky. If its clear then the problem is not likely in the lower unit. If thats the case then the oil is likely coming from the engine itself. Have you checked the oil level in the motor itself, assuming its a four stroke.
 

KJM

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I am really hoping I don't have to do that. I watched some videos last night and it looks like a pain in the butt. I was very surprised to see there was not a gasket for the lower unit.
You may not need to but if you do, its not that hard. You would need to to change your water impeller anyway so you might as well get everything done the one time.
 

Ranger09

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Aug 29, 2023
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I had a new impeller put on at the beginning of spring and a new peepop valve a little over a month ago. I probably won't get to it till Friday morning but if everything above the lower unit screws look fine Im gonna drain the lower unit, pull my prop off and do a pressure test to make sure the prop shaft seals are good.
 

99yam40

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I had a new impeller put on at the beginning of spring and a new peepop valve a little over a month ago. I probably won't get to it till Friday morning but if everything above the lower unit screws look fine Im gonna drain the lower unit, pull my prop off and do a pressure test to make sure the prop shaft seals are good.
can you explain what a peepop valve is
 

Ranger09

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Aug 29, 2023
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Im sorry, a poppet valve. My pee hole was shooting water out but my moter was overheating when I was running at idle speed for long distance. The poppet valve was not working properly. Im on Belton lake and the water level is 17 feet low so alot of places you have to idle through.
 

KJM

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Check your motor oil to make sure there isn't water in that. Overheating may have caused damage to the head gasket or the block?
 
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