I spent the weekend losing blood and bruising knuckles changing the impeller on my Yanmar 4JH3-TE. My boat is a Hunter Passage 450. What was Hunter thinking??? I have read numerous post on this subject but have lived the tale now. I would suggest removing the alternater first. (Which I didn't....at first) I have the shower cutout already but it only means that I can get one hand on the pump and my face crammed against the shower wall. Many times I would have like to actually SEE what I was doing. The impeller was glued to the shaft and required totally destroying to remove. This is where most of the blood and bruises came from. Pulling the blades with a pair of needle nose pliers and the sudden release caused my hand to slam against the back side of the starter. I changed the pump cover to the Speed Seal with knurled knobs but this means it will only take me one day to change the impeller. I only hope this new impeller last a long, long time.
Changing raw water impeller on 4JH3-TE Hunter 450
- Thread starter larrydynamic
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Actually the better question is "what was Yanmar thinking"? I understand that on the new Yanmars they've fixed this issue and the impeller is accessible from the front of the engine.
I do not know your layout be we put an access door on the port side of the engine. This makes for easy access. The clearance is still a problem.
You may want to try the new the new impellers and the special tool that makes extraction easier.
You may want to try the new the new impellers and the special tool that makes extraction easier.
Figured out a neat trick
The biggest problem is you can't see what you're doing, so you contort your body into really awful positions to try and get some sight of the cover, screws, and impeller.
So, here are some things you want to do.
When you take the screws off of the cover, replace them with stainless hex socket head screws. That way, you just load the screws onto a long Allen key, and the screw stays put. You can get Allen keys which fit into screwdriver handles, and you stack on an extension.
You can very lightly wrap the head of the screw with masking tape around the Allen key. It will stay totally on the key. Once it's threaded in, you just retract the key and the tape will come with it.
Next trick...
The problem is you still can't see what you're doing.
Go to a hobby supplier (Jameco), and buy a cheap miniature TV camera. They can be had for 30 bucks or so.
They have a composite video output.
On the hunter 49, take a long video cable, and plug it into the flat screen in the main salon. You will now have a honking big picture from this little camera.
Tape the camera to a flashlight. Now, position it so that the whole scene is filling your tv. You will find it very easy to work with long reach tools, and see exactly what you're doing.
The great thing is you will find many other uses for this setup on board when trying to find something dropped in a bilge, what's behind a panel, etc.
If you go on ebay, you'll find the cameras even cheaper than 30 bucks
Without question, changing the impeller in the 4Jh is a rotten exercise. Especially if you own a 49, where the engine is below floor level.
The biggest problem is you can't see what you're doing, so you contort your body into really awful positions to try and get some sight of the cover, screws, and impeller.
So, here are some things you want to do.
When you take the screws off of the cover, replace them with stainless hex socket head screws. That way, you just load the screws onto a long Allen key, and the screw stays put. You can get Allen keys which fit into screwdriver handles, and you stack on an extension.
You can very lightly wrap the head of the screw with masking tape around the Allen key. It will stay totally on the key. Once it's threaded in, you just retract the key and the tape will come with it.
Next trick...
The problem is you still can't see what you're doing.
Go to a hobby supplier (Jameco), and buy a cheap miniature TV camera. They can be had for 30 bucks or so.
They have a composite video output.
On the hunter 49, take a long video cable, and plug it into the flat screen in the main salon. You will now have a honking big picture from this little camera.
Tape the camera to a flashlight. Now, position it so that the whole scene is filling your tv. You will find it very easy to work with long reach tools, and see exactly what you're doing.
The great thing is you will find many other uses for this setup on board when trying to find something dropped in a bilge, what's behind a panel, etc.
If you go on ebay, you'll find the cameras even cheaper than 30 bucks
One other option
You can also buy a USB bore scope. This is a miniature camera with built in led illumination. It simply plugs into your laptop. They are all over ebay for 30 -40 bucks. Some have built in magnets. Last time I checked, magnets stuck to Diesel engine blocks, so totally hands free
You can also buy a USB bore scope. This is a miniature camera with built in led illumination. It simply plugs into your laptop. They are all over ebay for 30 -40 bucks. Some have built in magnets. Last time I checked, magnets stuck to Diesel engine blocks, so totally hands free
Impellers with built in removal mechanisim are available.
I have been buying impellers for my 4jh3e Yanmar that have been redesigned to include a removal device. The hub has a threaded fitting on the outer side. You buy a removal tool that has two parts. One is essentially a short squat bolt with the center drilled out and tapped. The other part is a bolt that screws in the center. The squat bolt screws into the hub. The the other screws in down the center. When the bolt hits the center of the impeller shaft it starts pulling the impeller straight out. Dreamboat is still on the hard an hour away so I cannot provide name right now but I buy them at a good local diesel engine parts supply house. He did have to call his supplier the first time I was in there but got them in the next day. I am pretty certain they are made by Johnson pumps. No more bruised knuckles!
I have been buying impellers for my 4jh3e Yanmar that have been redesigned to include a removal device. The hub has a threaded fitting on the outer side. You buy a removal tool that has two parts. One is essentially a short squat bolt with the center drilled out and tapped. The other part is a bolt that screws in the center. The squat bolt screws into the hub. The the other screws in down the center. When the bolt hits the center of the impeller shaft it starts pulling the impeller straight out. Dreamboat is still on the hard an hour away so I cannot provide name right now but I buy them at a good local diesel engine parts supply house. He did have to call his supplier the first time I was in there but got them in the next day. I am pretty certain they are made by Johnson pumps. No more bruised knuckles!
These are OEM Yanmar impellers
In my prior post I recommended buying these, but this solves only half the battle. You still need to get at it.
On the 49, this is extremely difficult
The impellers with the threaded center are from Yanmar. They cost a bunch more than Johnson.
In my prior post I recommended buying these, but this solves only half the battle. You still need to get at it.
On the 49, this is extremely difficult
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