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Alpha 2nd Gen lower unit knocking noise

S

SeaRayzor

Member
I finally got Mercruiser 5.0 MPI running perfectly and after teaching son how to wakeboard, I hit an underwater obstruction-maybe concrete?? and it started making a slight knock while in gear when puttin the boat back on the trailer.

Once out of the water, there was visible damage to the 14x19 19P propeller. I got prop re-worked and put it back on and was making the same noise. Shaft looks like it spins true. I rode the boat a little while and noise increased.

I put boat back on trailer and checked lower unit oil and it had water intrusion. While changing oil, I noticed that the sealing washer was missing from the drain/fill plug. Friend of mine helped me change the lower unit oil about a month before this ordeal, and apparently he didn’t know about the washer and it may have fell into used oil and he put the plug back without the washer not knowing.

Now I don’t know if the water intrusion was from the missing washer or from hitting the obstruction or just coincidence that the noise was heard after hitting obstruction and was already taking in water. Its a mystery.

Anyhow, I purchased new sealing washers and changed oil. There was a few shavings on the magnet but nothing alarming, I don’t think.

I just put it back in the water (we’re vacationing on Lake Hamilton Arkansas) and the knocking is still there. Even when not in gear with throttle up it has a slight knock.

I also bought a new Propeller with same result.

Anyone have an opinion on what it might be? Solutions to problems and how much $damage im looking at?

Sincerely,
SR
 
Most likely broke a tooth on the gear
Put boat on trailer and remove the top and back covers on the drive. Look at the teeth
 
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Is it safe to run like that? Will i cause more damage. I mean…im on vacation, I can’t do anything about it now.

You think the water intrusion was from plug washer?
 
SeaRayzor said:
Is it safe to run like that? Will i cause more damage. I mean…im on vacation, I can’t do anything about it now.

You think the water intrusion was from plug washer?
Click to expand...
New Merc Gen 2 is about $4K
New SEI Gen 2 is about $2K

The drive is knocking, something is wrong and most likely something is going to break. If it was my boat I wouldn't run it until found out what is wrong.

Make sure everyone onboard has a life jacket
 
SeaRayzor said:
Is it safe to run like that? Will i cause more damage. I mean…im on vacation, I can’t do anything about it now.

You think the water intrusion was from plug washer?
Click to expand...
yes if no sealing washer was on drain plug you can get water intrusion there. Also from other places.

As mentioned check gears by removing the top cap. If you hit something in the water it may be covered on insurance, or at least of friend of mines was. He felt a thud underway, was knocking after wards chipped teeth on lower gear (bravo drive).

AD lays out the drive costs not a lot of labor to change a drive. if it were mine I wouldn't run it especially under load of water sports but your call. Sucks while on vacation, but with basic hand tools you could have a drive over-nighted and on in a few hours if you are handy

here is a used one from a guy who parts out freshwater boats. If it passes pressure test should be ok if there was no water in bellows.

https://www.ebay.com/itm/3157597814...MI1sWr6OWvjgMVNU7_AR2QzBj8EAQYAiABEgIEQfD_BwE

Doug russell has both new and reman OEM drives $3 to $3.5k

 
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Dieter said:
yes if no sealing washer was on drain plug you can get water intrusion there. Also from other places.

As mentioned check gears by removing the top cap. If you hit something in the water it may be covered on insurance, or at least of friend of mines was. He felt a thud underway, was knocking after wards chipped teeth on lower gear (bravo drive).

AD lays out the drive costs not a lot of labor to change a drive. if it were mine I wouldn't run it especially under load of water sports but your call. Sucks while on vacation, but with basic hand tools you could have a drive over-nighted and on in a few hours if you are handy

here is a used one from a guy who parts out freshwater boats. If it passes pressure test should be ok if there was no water in bellows.

https://www.ebay.com/itm/3157597814...MI1sWr6OWvjgMVNU7_AR2QzBj8EAQYAiABEgIEQfD_BwE

Doug russell has both new and reman OEM drives $3 to $3.5k

Click to expand...
I live down the road from Diug Russels
 
kghost said:
I live down the road from Diug Russels
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I figured being in MA. Can you grab a drive and deliver it to this guy in AK by morning ?

Seriously only ordered small parts from DR over the years are they decent to deal with ? Seem to have a lot of parts , maybe top shelf pricing ??
 
D. R. Marine is an interesting place. Huge supply of engines in warehouse. Owner buys as many as possible from going out of business marinas and such.
I have done business with them for parts for years but they carry a lot of aftermarket parts.

I am not sure they have a merc license.

Many Years back they lost their merc license because they got caught selling new boats with used engines because they were pulling them and selling them as needed by customers and then installing a used/remanufactured engine and still selling boat as new.....

There is another large marine business a mile or so from DR marine which is a authorized merc/mercruiser dealer. When i need merc specific parts, I go there.
 
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