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My "how To" Change An Impeller On A Suzuki Dt85 1994


impulse

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I thought i would post some points and photos on changing an impeller and plate on a Suzuki DT85 as there didn't seem to be anywhere which had the info online. I'm also going to start a "How to" page on my crappy website to help others. I've had my Signature 492F for 3 years this Xmas 07 and thought it was about time to change the water pump impeller (shock horror i left it that long). My theory was to check the "Pee Hole" outlet making sure there was good pressure and flow. It seemed to be getting a little weaker so its was time to change it out.

The impeller kit only cost $50 so I would recommend people replace the impeller regularly although my was at least 3 years old (not sure when the last owner replaced it so it could of been longer)

Removal

  • Step 1. Put your motor into neutral, remove the spark plug leads (just incase) and make sure you have enough ground clearance between the bottom of the motor and the ground. You need to pull down the Drive Shift Rod and Driveshaft clear from the motor to remove the Gearcase. This is where the impeller is mounted. Some say you have to drain the Gearcase oil but if you have enough ground clearance I found you don't need to as you don't have to tilt the Gearcase to remove. (Note: the Water Pump Tube stays within the Driveshaft Housing).

  • Step 2. Loosen (But DO NOT REMOVE) the Nyloc nut on the Clutch Shaft Rod all the way and push the loosened nut & rod into the motor. This will detach the Drive Shift Rod which allows you to remove the Gearcase. See Pics below:

clutch_shift_access.jpg Clutch Shaft Rod, this is on the Starboard side of the motor just below the cowling covered by a rubber grommet.

clutch_shift_rod_nut.jpg The nut in the center is the one you need to loosen.

  • Step 3. Undo all 7 bolts around the Gearcase but only loosen the 2 nuts (1 on each side) as these will stop the Gearcase from falling off onto your foot. There are 7 bolts & 2 nuts altogether. One of the bolts are underneath the Gearcase behind the Trim Tab. (Note: There is a bolt on top of the Gearcase switch bolts down from the top to the bottom, this does not need to be removed).

  • Step 4. Once you have removed the 7 bolts and only loosened the 2 nuts, the Gearcase may have already slid down to the loosened nuts. If not, give the Gearcase a light tap and it should slide off. I positioned a piece of timber under the Gearcase and then removed the last remaining nuts. I managed to lift & hold the Gearcase up, removed the timber and then slide the Gearcase clear of the Driveshaft housing. I needed to use the power tilt to tilt the motor back to gain some more ground clearance, just make sure you tilt and remove the Gearcase evenly. You may need someone to give you a hand as the Gearcase weighed approx 20kg. Make sure you slide the Gearcase off evenly as you might damage the splines on the Driveshaft or the Drive Shift Rod.

  • Step 5. Place the Gearcase somewhere......(I didn't think of this until after I was holding the bloody thing in the air). I placed it into a 20L drum which held it fairly square so I could work on it. You could place it in a vice just make sure you have some protection on the jaws.
    You will then see the impeller housing (pic below) which has 4 nuts. Remove the nuts and cover and note how the fins are laying on the old impeller. You have to make sure you install the new impeller the same way.
    Remove the old impeller by sliding it up the Driveshaft but be careful you don't drop the small Keyway as you might need this if your not replacing it. The Keyway stops the impeller from rotating freely on the shaft and locks it into place. Remove the Keyway.
    You will then see the impeller plate under the impeller that you may or may not elect to replace. When you buy a replacement impeller you can buy the impeller itself or a kit which contains the impeller, plate, keyway and gasket. If you are replacing the plate (why not as you have gone this far) remove the plate and gasket, make a not which way the plate is installed as you may need to refer back to this depending on the kit you buy.

impeller_housing.jpg Nuts removed, the small rod you see is the Gearshift Rod, the large one is the Driveshaft.

impeller.jpg Cover removed, notice how the Fins of the impeller are laying.

impeller_plate_removed.jpg Plate removed

  • Step 6. After you remove the impeller housing inspect if for excessive damage and/or cracking, if there are deep scratches or cracks I'd recommend you replace the housing. Clean the surface of the housing as this faces the plate and there is no gasket between the housing and the plate. I use an emery stone and Inox to clean the surface. If you use this technique, move the case in a figure 8 motion on the emery stone as this will help to make sure you "linish" the surface evenly.
    Clean the surface of the Gearcase where the new plate will be installed, I used a small razor blade but make sure you don't scratch the surface deeply as the gasket may not seal.

impeller_housing_cleaned.jpg All clean ready to be installed.

keyway.jpg The Keyway is the small rectangular piece of metal (left) at the base of the Driveshaft.

Installation

  • Step 7. In the impeller kit (if your replacing the plate as well) you will notice you have a new impeller, plate, gasket and Keyway. If you bought the impeller only then you need to keep the other parts.
    Look inside the new impeller and you will see a small notch which is open on one side (See pic). This notch is where the Keyway sits so you have to make sure that when you insert the impeller into the housing, this notch is facing down so it goes over the Keyway on the Driveshaft.
    Insert the new impeller into the housing making sure the "fins" are laying the same way as the old impeller, (I didn't take a photo of the impeller in the housing but if you see the one in Step 5 you will notice how the old impeller fins are laying).I sprayed some Inox on the new impeller and inside the housing to protect the impeller from the first test run, you could use some engine oil as well.

  • Step 8. Now depending on who you are you might want to add some silicon sealer to the Gearcase and the bottom of the plate before installing them but this is your choice, I did.
    Place the gasket onto the Gearcase and then the new plate (Note: The kit I bought showed which way the plate went ie it was marked "Top", if not refer back to step 5).
    Place the new Keyway into the Driveshaft, slide down the impeller housing (with the impeller inside) down the Driveshaft and align the keyway with the notch in the impeller. Tighten the nuts evenly taking note that the Gearcase is aluminum so don't be heavy handed.
    Place some grease onto the side of the Driveshaft splines, don't put grease on the top of the shaft as depending on the motor it might cause undue pressure inside the gearing.
    I also cleaned and aplied some grease to the water pipe grommet inside the Driveshaft housing (see pic)

impeller_keyway.jpg Note the notch for the Keyway

driveshaft_waterpipe.jpg The water pipe is the round fitting you see at the top.

  • Step 9. Now for the hard bit.
    Before you start aligning the Gearcase back onto the motor grab a BIG socket (30mm) and place it onto the fly wheel nut so you can rotate the motor as you align the Gearcase. If you don't have a socket you could use a rag on the teeth as you only need to rotate a small amount.
    Also make sure that the Clutch Shaft Rod is pushed into the motor all the way (Step 2). If it isn't it will foul the Drive Shift Rod and the Gearcase will not slide into place.
    Another grey point hear is whether you place a bead of silicon sealer on the surface of the Gearcase, I did.
    Grab you Gearcase and carefully slide the Driveshaft and Drive Shift Rod up inside the Driveshaft housing. You may need to rotate the motor clockwise to align the Driveshaft. Make sure you don't knock the Drive Shift Rod as this will put the gearbox in gear which won't align with Clutch Shift Rod which is in Neutral. If you slid it up the first go and it aligned, use the 2 nuts to hold the Gearcase in place.
    If you do knock the Drive Shift Rod and it went into gear remove the Gearcase and place a screwdriver into the hole on top of the Drive Shift Rod and pull it up or down until it goes into Neutral. You can check if the gearbox is in neutral by spinning the prop, it should spin freely in both directions when its in Neutral.
    Before you install the remaining bolts, tighten up the Clutch Shaft Rod nut and test the gears. Once you have tighten the nut place it in forward and check that the prop only spins clockwise and not anti-clockwise. Place it back into Neutral and test it rotates freely both ways.
    If all is well tighten up the remaining bolts evenly and again don't be heavy handed as they are screwing into aluminum.

Thats it, it isn't difficult but only needs some procedures to make sure certain things are done in order.

If there is some info here that you disagree with then let the know and I'll update the post if warrantied.

I will post a second post with some more pictures and links.

Edited by impulse
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  • 8 years later...

I thought i would post some points and photos on changing an impeller and plate on a Suzuki DT85 as there didn't seem to be anywhere which had the info online. I'm also going to start a "How to" page on my crappy website to help others. I've had my Signature 492F for 3 years this Xmas 07 and thought it was about time to change the water pump impeller (shock horror i left it that long). My theory was to check the "Pee Hole" outlet making sure there was good pressure and flow. It seemed to be getting a little weaker so its was time to change it out.

The impeller kit only cost $50 so I would recommend people replace the impeller regularly although my was at least 3 years old (not sure when the last owner replaced it so it could of been longer)

Removal

  • Step 1. Put your motor into neutral, remove the spark plug leads (just incase) and make sure you have enough ground clearance between the bottom of the motor and the ground. You need to pull down the Drive Shift Rod and Driveshaft clear from the motor to remove the Gearcase. This is where the impeller is mounted. Some say you have to drain the Gearcase oil but if you have enough ground clearance I found you don't need to as you don't have to tilt the Gearcase to remove. (Note: the Water Pump Tube stays within the Driveshaft Housing).
  • Step 2. Loosen (But DO NOT REMOVE) the Nyloc nut on the Clutch Shaft Rod all the way and push the loosened nut & rod into the motor. This will detach the Drive Shift Rod which allows you to remove the Gearcase. See Pics below:
clutch_shift_access.jpg Clutch Shaft Rod, this is on the Starboard side of the motor just below the cowling covered by a rubber grommet.

clutch_shift_rod_nut.jpg The nut in the center is the one you need to loosen.

  • Step 3. Undo all 7 bolts around the Gearcase but only loosen the 2 nuts (1 on each side) as these will stop the Gearcase from falling off onto your foot. There are 7 bolts & 2 nuts altogether. One of the bolts are underneath the Gearcase behind the Trim Tab. (Note: There is a bolt on top of the Gearcase switch bolts down from the top to the bottom, this does not need to be removed).
  • Step 4. Once you have removed the 7 bolts and only loosened the 2 nuts, the Gearcase may have already slid down to the loosened nuts. If not, give the Gearcase a light tap and it should slide off. I positioned a piece of timber under the Gearcase and then removed the last remaining nuts. I managed to lift & hold the Gearcase up, removed the timber and then slide the Gearcase clear of the Driveshaft housing. I needed to use the power tilt to tilt the motor back to gain some more ground clearance, just make sure you tilt and remove the Gearcase evenly. You may need someone to give you a hand as the Gearcase weighed approx 20kg. Make sure you slide the Gearcase off evenly as you might damage the splines on the Driveshaft or the Drive Shift Rod.
  • Step 5. Place the Gearcase somewhere......(I didn't think of this until after I was holding the bloody thing in the air). I placed it into a 20L drum which held it fairly square so I could work on it. You could place it in a vice just make sure you have some protection on the jaws.

    You will then see the impeller housing (pic below) which has 4 nuts. Remove the nuts and cover and note how the fins are laying on the old impeller. You have to make sure you install the new impeller the same way.

    Remove the old impeller by sliding it up the Driveshaft but be careful you don't drop the small Keyway as you might need this if your not replacing it. The Keyway stops the impeller from rotating freely on the shaft and locks it into place. Remove the Keyway.

    You will then see the impeller plate under the impeller that you may or may not elect to replace. When you buy a replacement impeller you can buy the impeller itself or a kit which contains the impeller, plate, keyway and gasket. If you are replacing the plate (why not as you have gone this far) remove the plate and gasket, make a not which way the plate is installed as you may need to refer back to this depending on the kit you buy.

impeller_housing.jpg Nuts removed, the small rod you see is the Gearshift Rod, the large one is the Driveshaft.

impeller.jpg Cover removed, notice how the Fins of the impeller are laying.

impeller_plate_removed.jpg Plate removed

  • Step 6. After you remove the impeller housing inspect if for excessive damage and/or cracking, if there are deep scratches or cracks I'd recommend you replace the housing. Clean the surface of the housing as this faces the plate and there is no gasket between the housing and the plate. I use an emery stone and Inox to clean the surface. If you use this technique, move the case in a figure 8 motion on the emery stone as this will help to make sure you "linish" the surface evenly.

    Clean the surface of the Gearcase where the new plate will be installed, I used a small razor blade but make sure you don't scratch the surface deeply as the gasket may not seal.

impeller_housing_cleaned.jpg All clean ready to be installed.

keyway.jpg The Keyway is the small rectangular piece of metal (left) at the base of the Driveshaft.

Installation

  • Step 7. In the impeller kit (if your replacing the plate as well) you will notice you have a new impeller, plate, gasket and Keyway. If you bought the impeller only then you need to keep the other parts.

    Look inside the new impeller and you will see a small notch which is open on one side (See pic). This notch is where the Keyway sits so you have to make sure that when you insert the impeller into the housing, this notch is facing down so it goes over the Keyway on the Driveshaft.

    Insert the new impeller into the housing making sure the "fins" are laying the same way as the old impeller, (I didn't take a photo of the impeller in the housing but if you see the one in Step 5 you will notice how the old impeller fins are laying).I sprayed some Inox on the new impeller and inside the housing to protect the impeller from the first test run, you could use some engine oil as well.

  • Step 8. Now depending on who you are you might want to add some silicon sealer to the Gearcase and the bottom of the plate before installing them but this is your choice, I did.

    Place the gasket onto the Gearcase and then the new plate (Note: The kit I bought showed which way the plate went ie it was marked "Top", if not refer back to step 5).

    Place the new Keyway into the Driveshaft, slide down the impeller housing (with the impeller inside) down the Driveshaft and align the keyway with the notch in the impeller. Tighten the nuts evenly taking note that the Gearcase is aluminum so don't be heavy handed.

    Place some grease onto the side of the Driveshaft splines, don't put grease on the top of the shaft as depending on the motor it might cause undue pressure inside the gearing.

    I also cleaned and aplied some grease to the water pipe grommet inside the Driveshaft housing (see pic)

impeller_keyway.jpg Note the notch for the Keyway

driveshaft_waterpipe.jpg The water pipe is the round fitting you see at the top.

  • Step 9. Now for the hard bit.

    Before you start aligning the Gearcase back onto the motor grab a BIG socket (30mm) and place it onto the fly wheel nut so you can rotate the motor as you align the Gearcase. If you don't have a socket you could use a rag on the teeth as you only need to rotate a small amount.

    Also make sure that the Clutch Shaft Rod is pushed into the motor all the way (Step 2). If it isn't it will foul the Drive Shift Rod and the Gearcase will not slide into place.

    Another grey point hear is whether you place a bead of silicon sealer on the surface of the Gearcase, I did.

    Grab you Gearcase and carefully slide the Driveshaft and Drive Shift Rod up inside the Driveshaft housing. You may need to rotate the motor clockwise to align the Driveshaft. Make sure you don't knock the Drive Shift Rod as this will put the gearbox in gear which won't align with Clutch Shift Rod which is in Neutral. If you slid it up the first go and it aligned, use the 2 nuts to hold the Gearcase in place.

    If you do knock the Drive Shift Rod and it went into gear remove the Gearcase and place a screwdriver into the hole on top of the Drive Shift Rod and pull it up or down until it goes into Neutral. You can check if the gearbox is in neutral by spinning the prop, it should spin freely in both directions when its in Neutral.

    Before you install the remaining bolts, tighten up the Clutch Shaft Rod nut and test the gears. Once you have tighten the nut place it in forward and check that the prop only spins clockwise and not anti-clockwise. Place it back into Neutral and test it rotates freely both ways.

    If all is well tighten up the remaining bolts evenly and again don't be heavy handed as they are screwing into aluminum.

Thats it, it isn't difficult but only needs some procedures to make sure certain things are done in order.

If there is some info here that you disagree with then let the know and I'll update the post if warrantied.

I will post a second post with some more pictures and links.

hi just joined the forum from bonny scotland,discovered the site by searching for info on how to change the impeler waterpump on a dt75 but i cant see the images here is there a reason for that i realise the op is from years back but hope someone can help get them back thanks tight lines

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hi just joined the forum from bonny scotland,discovered the site by searching for info on how to change the impeler waterpump on a dt75 but i cant see the images here is there a reason for that i realise the op is from years back but hope someone can help get them back thanks tight lines

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hi just joined the forum from bonny scotland,discovered the site by searching for info on how to change the impeler waterpump on a dt75 but i cant see the images here is there a reason for that i realise the op is from years back but hope someone can help get them back thanks tight lines

Hi rab and welcome.

This member posted these pics on his "own crappy website" back in 2008 as he says in his first post.

The site is now not open anymore by the looks of it - none of us can see any pics.

If you have current questions then make a new post in the workshop or boating and someone will help you

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  • 3 years later...

Great write up. Could not of done my Suzuki  85 impeller without this. 
I had to adjust my shifter. 
I loosened a 8 mm nut in the cable ending in cowling, removed the plastic lug from the linkage pin and turn the lug to adjust the neutral position, then re tightened but. This adjustment stopped the grinding noise noticed  when changing the gear selector. BCDBA017-118A-4022-BF18-A04C9DD377BA.thumb.jpeg.e2bb0388b9240821328513243f350ee1.jpeg

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