How to replace an impeller on a Mercury inboard

How to replace an impeller on a Mercury inboard

Hello, and thank you for stopping by. In this video, i will take you step by step on how to change the impeller on your inboard boat.

First off, let me just tell you that regardless if you’re changing the fluid on your transmission.. you will still leak some out when you separate the lower end, and will have to replace whatever spilled.

*Somewhere around 0:35 when you remove the 1/2″ bolt from the back part, you will have to remove the rubber hose (clip)
Check 9:15 for reference.

Ratchet + extension
16mm or 5/8″ wrench
1/2″ socket
9/16″ socket
8mm or 5/16″ socket
flat screwdriver

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GT's Performance says:

Here are some tabs to help you navigate through the video.
0:00 Removing Lower Unit
2:55 Removing Impeller
4:17 Installing Impeller
6:13 Installing Lower Unit
9:30 Adding Oil
12:16 Tools / Recap

Gary Franco says:

Great video man. Very detailed and good camera action to see every part of the removal and install. Question; is there a diference in install if it's a bigger engine? I have a Mercruiser 5.0

Cam Gregg says:

Do you have to change the oil to change the impeller? It will be a mess if you don't?

Kevin Keller says:

A great video but pump the brakes. STOP! It is not necessarily true that you rotate the shaft clockwise. I know for a "FACT" that our Merc 3.0 Alpha One lower unit, Which looks exactly like this unit, rotates COUNTER clockwise!! If you install the impeller with the vanes of the impeller rotating in the wrong direction it will not pump and you will overheat the motor. The only way to truly know which way to install the impeller is to take a picture before you remove it or better yet, put the lower unit in gear when its off and put the shift lever in drive. As you rotate the prop as if the boat was moving forward, take notice which way the shaft rotates. This will ensure you have the vanes in the right direction when you install the cover. Trust me I have made this very mistake!!

Jesus Carranza says:

Hey bro have you work on removing the gimbal bearing and the bellows… I'm doing this job this weekend and I have a question .. I have the alignment tool to check the alignment of the engine and outdrive my question is do I check for alignment before removing the gimbal bearing or wait until I'm all done with the job thanks

Jesus Carranza says:

It does the clicking when I'm barely going into reverse or forward position then it goes away

Jesus Carranza says:

Is this part of the shifting cable?

Jesus Carranza says:

Ok.. but it doesn't do the clicking noise on neutral it only does it when the boat on and I put it in forward or reverse gear

Jesus Carranza says:

Okay I did I put it in forward and it locks.. but if I spin it the other way well being in forward I will get a clicking noise?

Jesus Carranza says:

Hey bro I just change my water pump.. I installed everything the same way you did in your video.. put some lower gear oil on it.. but now I'm getting a clicking noise when going in forward gear or reverse.. what do you think it's the problem thanks

scooter13 says:

FYI its called lower unit not transmission.

No Name says:

Excellent job on this tutorial. Was wondering about torqueing fasteners. Why no torqueing? Got a new project and familiarizing myself and this was a great help. Definate subscribe and 2 thumbs up.

Jesus Carranza says:

When changing the impeller did you leave the gear on forward or neutral


Could not have been shown any better, THANK YOU !!

Philip Tolentino says:

I have a 1990 Baja 454 IO 365 hp. Bravo 1. Your video is very helpful! I have a question during removal of Impeller pump housing. My motor has the fuel pump and fuel water separator on same side as the water pump impeller. My question is, do I need to loosen the belt for the fuel pump before removing the impeller housing? Thanks in advance and the great video!

peteraguila1 says:

Man just broke my lower unit looks easy. To replace pague mucho por el replace

elimonjal says:

Thank you for this video, esta chingon, its the best I have seen, your photography is great. good explanation. this is what i am trying to do for 2 days, but when i try to connect the lower unit, the shaft won´t slide up. it hits metal. have my gear it forward. i notice you are moving the shift stick in the back, is that so it will slide up ??? because i know its suppose to be straight, it pulls to the right, what is the secret ? also, i saw a man say to his helper to move the propeller. confused Pete, thank you. Gracias tecnico. por favor dime como le hago.??? what city are you in.?? another question, water was not going up to the engine, i disconnected the hose in the thermostat, and no water. so I thought its the water pump. but also could be its clogged, how can I find out which. thank you

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