Disclaimer: These instructions likely cover many different models other than the one I have. I don’t know which models these are, so if you don’t have the same engine as mine then be sure to check on it.
Having said the above, you may find the these instructions can apply to Evinrude and Johnson engines made around the 1970’s or 1980’s and with lower HP. I’m not sure about the higher HP models, but these may be included to.
If you know more about this, let me know so I can update the above.
My engine is an Evinrude 115hp 115893c.
The below images are all the steps taken to disassemble the bottom end, replace the impeller, and reassemble. All images are in order and have detailed captions describing the process.
If you found this post useful, please Like it, tell your friends, follow me, light a candle, whatever. Just do something! 🙂
Accessing the gear shift linkage begins with removing the accelerator and gear shift cable arms from the engine
Removing accelerator cable arm
A metal bracket is normally screwed on to keep the two arms in place and to avoid unwanted adjustment of the arms. I’ve removed it here.
In order to access the gear linkage to release the lower unit, you need to remove the hinged bit in the middle.
There is a spring inside that will make everything fly apart, so i’ve used a cable tie to keep it together.
Remove the bracket for the gear shift linkage, this gives better access to the screw we need to get at.
At this point, you could try your luck and try to remove the screw for the linkage (see a few picture below to see where it is), or just pull off the carbys to very easily get to it. I’ve done this before and found it impossible to get to the screw (and replace it when all is done) so I am just removing them. Take off the air filter cover.
Remove the carby cover.
When removing the carby cover be careful to remove this plastic piece for the choke, it can easily break
Also the choke wire needs to be taken off. To undo the connector you slide one of the wires up so it is 90 degrees to the other.
There is also a hose connected to the bottom right of the carby cover. Remove this carefully. Once removed, the whole cover will come away.
Now to take off the carbys. Each one is held together with 4 nuts (with washers) keep each one in place. You will need to progressively unscrew them as the two nuts on the bottom of each carby cannot come off fully without loosening the carby a bit first.
Use a spanner to loosen the nuts. Remember the order in which you took them off as it would be easiest to put them back in reverse order.
This is the fuel pump. It uses a diaphragm which pumped using compression from inside the engine (there is a small hole in the casing behind the pump where it gets this pressure from). Remove the two bottom screws only and the pump should come away. There is a gasket behind the pump, save this for reuse when reassembling.
The fuel pump plugs directly to the two carbys via a T-piece hose. You can either remove it entirely to make it easier to work with or let it hang like I have. While you are here, inspect the hoses for damage/cracks.
You can see the fuel pump gasket on the right side. My one had stuck itself to the casing, so I left it there. This gasket can be reused.
In the middle just below the lower carby you will see this bold. This is the linkage for changing gears (forward/reverse/neutral). Remove this bolt and pull out the arm it was holding in place.
A view from the left side of the engine (when viewed from inside the boat). You will need to remove the knuckle that held the linkage in the previous picture. What you will be left with is just a rod with a hold in the end. This rod goes down in to the bottom end (gear case). When it is moved up/down by the arm you just removed it changes the gears. You are now ready to take unbolt and remove the entire bottom end.
There are two bolts on either side of the bottom end (aka gear case) plus 3 more bolts just above the prop. One of the bolts is underneath the anode so you will need to remove that first.
You can see two of the bolts that hold the bottom end in place. The left side shows where the anode was removed. The final bolt is between the left side and right side bolts, inside the cavity.
A pic showing inside the cavity and where the bolt goes as mentioned in previous pic.
The bottom end should just drop down at this point. Make sure you have something soft for it to land on (other than your foot!)
Tilt the engine all the up to remove the bottom end. The two long shafts are the gear shift rod (left) and the drive shaft (right). There is also a copper pipe (not pictured) which easily comes out. This is used for pumping water up to the engine for cooling. The end of it sits inside the plastic housing on the right of the drive shaft.
Clean up and inspect the shaft.
Instruction sheet that came with the impeller replacement kit.
Impeller replacement housing.
Removing the old impeller housing. Just a few bolts around the housing.
Shaft spline. That rubber seal will also be replaced. A new one should’ve come in your impeller kit.
The impeller spins with the shaft. Make sure you put the blades of the impeller in the same rotational direction as the old one.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. This was seized! had to tap it out (carefully)
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. Cleaning out any crud.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. Exposing the bearings. This is supposed to be sealed to water, but you can see the seal was broken.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. Exposing the bearings. This is supposed to be sealed to water, but you can see the seal was broken.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. Exposing the bearings. This is supposed to be sealed to water, but you can see the seal was broken.
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. You don’t need to remove this piece for only an impellor replacement, move along. Nothing to see here.
In an earlier service I noticed I didn’t have a main/large gasket to stop water leaks coming out the edges of the bottom end – so I used gasket sealer (the red stuff you see all along the end of the mating surfaces). I still don’t know if there is supposed to be a gasket here (I doubt it) but because there isn’t much pressure at this point it is fine to use some gasket maker/sealer. Just make sure it is resistant to heat and salt water. Using sand paper remove any old sealant (im using Wet&Dry 320. It takes longer to clean it up at least I won’t damage the surface).
OK, 320 grit was too slow. I’m using sandpaper drill bit now. Much quicker!
NOTE: My bottom end was leaking gearbox oil which I was certain was coming from here. If you are just changing the impeller you do not need to remove this section or follow instructions here. You don’t need to remove this piece for only an impellor replacement, move along. Nothing to see here.
Cleaning up the surfaces with more sandpaper.
I use Hylomar to ensure a good gasket seal. Make sure you read directions before use.
To prevent the bolts from seizing I put a thin coat of grease on them before tightening.
Instructions mentioned something about a sealer/glue for this bit. I looked online and it seems OK to use a gasket maker. Just make sure the parts stay in place when assembling. I used the same thing for the rubber ring below the metal cup.
Push the new impeller in place while rotating it anti-clockwise.
Turn the impeller while in the cup until you get its hole fairly closely lined up to the cups hole.
Ignore this pic if you are only doing the impeller.
Ignore this pic if you are only doing the impeller.
Ignore this pic if you are only doing the impeller. I didn’t have a rubber ring for this, so I used some gasket maker. There shouldn’t be too much pressure here so it _should_ hold (initial tests show that it held).
Ignore this pic if you are only doing the impeller.
Ignore this pic if you are only doing the impeller.
Ignore this pic if you are only doing the impeller.
Put the key back in the shaft. Check how the impeller housing will fit on the shaft and rotate either the impeller or the shaft so that the key lines up with the key hole in the impeller. Do this before you slide the impeller housing on the shaft.
Knock it in place with a hammer.
Slide the impeller housing on the shaft and line up the key and the key hole.
Once in place, put in a couple of the bolts for the housing and hand tighten. Then try spinning the shaft and make sure all is moving properly.
Bolt in the impeller housing and the housing/holder for the copper pipe (for the engine cooling system). Replace other seals etc.
This metal thing on the left is for the exhaust. Replace it along with the rubber seals on its top and bottom. One you’re certain everything is completed then put a thin bead of sealant around the main mating surfaces and put the bottom end back on the engine. You may need the help of a friend to get it in place and bolt it up. Be sure to use grease on all bolts. Be sure the copper water pipe is in place too.
The procedure used to put everything back together is the reverse of how you pulled it apart, so no pictures were taken of this.
If you are having trouble getting the drive shaft spline in place then try twisting the flywheel a bit so the spline gears can match up to the hole in the crank shaft.
This was really informative, have the same issues with my Evinrude. I tried searching about these on Evinrude service manuals as well, but so far I think these instructions from your article will do. Thanks again!
Hey, very good instructions, i am ready to tackle the project now. thanks……………Have you ever removed the head? On mine, the threads are striped in the spark plug hole. It’s the lower cylinder on the fuel pump side. I have the exact same motor as you and i’m wondering if you have done any work in that area, and if you have any words of wisdom for me there. Thanks
Hey mate. Glad the post was useful to you.
Yep, same thing happened to my lower cylinder too. I ended up using a Helicoil to create a new thread. New one (steel) is stronger than the old one (aluminium). Google for Helicoil (or other brand) and get a kit which has a few of the coils in case you need to end up doing it for the other cylinders too.
Word of warning. Be sure to torque things correctly. The aluminium block is very easy to strip of its threads, as you found.
Good luck!
Did you have any problems with the head bolts (like braking off in the block) or with the actual head being stuck to the block? Thanks again
Never had issues with the head bolts. You will be hard pressed to break those. But the smaller water jacket cover bolts break off easily, careful with those. If you break it you’ll need to drill it out a replace it. If you don’t then water will leak through. Luckily those don’t hold nearly as much pressure as the head bolts. I had broken one before and ended up having to use Silastic to fix it. It worked 🙂
Good luck!
thanks for all yer help…..
Great how-to for the lower unit removal and impeller replacement. Have come back to this thread a few times for various situations.
Not sure if you still peruse this thread – but I’d love to pick your brain as I have the same motor, 115893c, and have found few resources that cover the litany of issues that have arisen.
Best
Matt
Hey Matt. Yes, I get notifications when a new comment is added. I’d be happy to try and help but it’s been so many years since I’ve had that engine I’m not sure how useful I can be.
I’ve had this motor for about 3 years, and it’s always had issues with starting, idling, trim – seemingly minor issues. Most of the time I can get it to behave and run as I need it to for quick jaunts around the lake.
Of late, it has been even more difficult to start, seems to misfire more, and idling at a normal RPM is difficult to say the least. On muffs it idles around 1200, with the occasional drop down to the 650-800 range. When it gets down to that range, it seems to either misfire or cough on one of the cylinders.
I’ve rebuilt the carbs, replaced ign coils and plugs/wires, and today found out that a few of the reed valves in the motor are not sealed properly.
I’m hoping that is the issue, and it isn’t a symptom of another larger issue. I have not done timing yet as I can’t get it to start or idle worth a damn, being able to do an idle timing adjustment letalone a WOT adjustment seems out of the question if I can’t get it to idle.
I suppose my question is, do you have any advice for where to go from here?
Thanks,
Matt
Since you’ve already rebuilt the carbs and replaced ignition components let’s assume that all good. Fixing The unsealed reed valves is crucial as they can cause air leaks, poor fuel atomisation, and the misfiring you’re experiencing. Replacing/repairing the reed valves should stabilise the air-fuel mixture and improve starting and idling.
Also, how is your compression? Generally, you want all cylinders to be about the same. Even with worn rings (lower compression).
Once that is done you can work on timing. You can try to increase idle on the carbs if that helps to work on the timing.
That was my thought – once the new parts arrive mid next week, I can put it back together and ideally get it to respond normally and try to t/s the timing if need be.
I haven’t tested compression this year, last year when it was at the shop for a check up they said between 110-115 on all cylinders, no excessive wear in the cylinder sleeves, and no rust in the crankcase or cylinders. Ill have to pick up a compression tester to verify current pressure.
Can I do I comp test if I’ve got the carbs/ leaf valves off?
This was really informative, have the same issues with my Evinrude. I tried searching about these on Evinrude service manuals as well, but so far I think these instructions from your article will do. Thanks again!
Hey, very good instructions, i am ready to tackle the project now. thanks……………Have you ever removed the head? On mine, the threads are striped in the spark plug hole. It’s the lower cylinder on the fuel pump side. I have the exact same motor as you and i’m wondering if you have done any work in that area, and if you have any words of wisdom for me there. Thanks
Hey mate. Glad the post was useful to you.
Yep, same thing happened to my lower cylinder too. I ended up using a Helicoil to create a new thread. New one (steel) is stronger than the old one (aluminium). Google for Helicoil (or other brand) and get a kit which has a few of the coils in case you need to end up doing it for the other cylinders too.
Word of warning. Be sure to torque things correctly. The aluminium block is very easy to strip of its threads, as you found.
Good luck!
Did you have any problems with the head bolts (like braking off in the block) or with the actual head being stuck to the block? Thanks again
Never had issues with the head bolts. You will be hard pressed to break those. But the smaller water jacket cover bolts break off easily, careful with those. If you break it you’ll need to drill it out a replace it. If you don’t then water will leak through. Luckily those don’t hold nearly as much pressure as the head bolts. I had broken one before and ended up having to use Silastic to fix it. It worked 🙂
Good luck!
thanks for all yer help…..
Great how-to for the lower unit removal and impeller replacement. Have come back to this thread a few times for various situations.
Not sure if you still peruse this thread – but I’d love to pick your brain as I have the same motor, 115893c, and have found few resources that cover the litany of issues that have arisen.
Best
Matt
Hey Matt. Yes, I get notifications when a new comment is added. I’d be happy to try and help but it’s been so many years since I’ve had that engine I’m not sure how useful I can be.
I’ve had this motor for about 3 years, and it’s always had issues with starting, idling, trim – seemingly minor issues. Most of the time I can get it to behave and run as I need it to for quick jaunts around the lake.
Of late, it has been even more difficult to start, seems to misfire more, and idling at a normal RPM is difficult to say the least. On muffs it idles around 1200, with the occasional drop down to the 650-800 range. When it gets down to that range, it seems to either misfire or cough on one of the cylinders.
I’ve rebuilt the carbs, replaced ign coils and plugs/wires, and today found out that a few of the reed valves in the motor are not sealed properly.
I’m hoping that is the issue, and it isn’t a symptom of another larger issue. I have not done timing yet as I can’t get it to start or idle worth a damn, being able to do an idle timing adjustment letalone a WOT adjustment seems out of the question if I can’t get it to idle.
I suppose my question is, do you have any advice for where to go from here?
Thanks,
Matt
Since you’ve already rebuilt the carbs and replaced ignition components let’s assume that all good. Fixing The unsealed reed valves is crucial as they can cause air leaks, poor fuel atomisation, and the misfiring you’re experiencing. Replacing/repairing the reed valves should stabilise the air-fuel mixture and improve starting and idling.
Also, how is your compression? Generally, you want all cylinders to be about the same. Even with worn rings (lower compression).
Once that is done you can work on timing. You can try to increase idle on the carbs if that helps to work on the timing.
That was my thought – once the new parts arrive mid next week, I can put it back together and ideally get it to respond normally and try to t/s the timing if need be.
I haven’t tested compression this year, last year when it was at the shop for a check up they said between 110-115 on all cylinders, no excessive wear in the cylinder sleeves, and no rust in the crankcase or cylinders. Ill have to pick up a compression tester to verify current pressure.
Can I do I comp test if I’ve got the carbs/ leaf valves off?