I did the same on my Nissan/Tohatsu 18 hp 2-stroke, manufactured in the early 90's. Renewed only the impeller, interestingly there were no seals, alignment studs were solid on the pump housing and pump had only 3 bolts. An easy job, but I just forgot to put back some geat linkage parts etc...took me extra 10 mins. Now it works great and squirts instantly :)
Thanks for posting this! I have the same engine and was about to tackle the impeller for the first time. Glad you showed the box and part number for the kit, as I was about to order just the impeller. This helps a lot.
Have a 1990 Nissan NS 40. Motor is overheating and water flow from impeller is weak. Going to try this as I have never replaced impeller over all these years. Will also replace the thermostat. Engine has been a champ for 30+ years. Want to milk it as long as I can. Thanks for posting the video. Helped me decide on a DIY vs. taking it in to a dealer for the work.
Great video. Just a suggestion: use a putty knife to remove those gaskets. That chisel might gouge the housing. This from watching my grandpa who was a jet mechanic and dad who was a factory mechanic work on things
No gasket between the lower pump housing and lower unit itself, just gaskets for the wear plate on this model. No silicone necessary either. Ideally, you would not want to reuse those roll pins but otherwise a very good job overall. For not having a service manual, you had pretty good instincts to not to over-tighten bolts on the aluminum housing as well as lubricating the impeller and drive shaft splines and orienting the impeller vanes correctly. The once a year interval is overkill in most situations. If you're in harsher running in environments (think sand, mud, excessive vegetation) or you rack up excessive hours then it might not be a bad idea. They do dry rot over time. I'd be willing to bet that one had not been changed for a long time and was obviously still in pretty good condition. Usually when the pump is going out it will give you a little bit of a warning with a weaker stream at idle (assuming no blockages in the internal water passages or tubing). Do keep up with lower unit oil changes though. If you get a leaky seal you can catch it (milkshake) before long-term damage is done to the lower unit. You should be able to have that anti-cavitation plate re-welded fairly inexpensively. Be careful with that hydrofoil, those can break even a good anti-cavitation plate and you have a good bit of yours missing. Replace the anode when about 50% gone. The 40D was one of the best engines Tohatsu has ever produced. I randomly found this while watching your Saab brake videos. Gotta love CZcams.
Great information. I have a 1700 Key West Sportsman. It came with the 40D tahasu outboard motor. The boat has been used continuously since new on the lower chesapeake bay. Thousands of hours. Still running well. Weekly fishing trips to the HRBT on 10gals of gas
Well done Matthew, few if any how to's actually show all the steps needed to R&R a lower unit start to finish no matter the need for removal great video!
Question regarding your Tohatsu - I'm trying to troubleshoot my used but new to me nissan 25 HP from the early 90's that doesn't seem to be peeing after startup. I've swapped my impeller/seals/cup but the motor still doesn't pee. Do you get stream on yours immediately after a cold start or does it need to warm up first?
Daniel. That is a really good question. I have been concerned about mine this year as it doesn't seem to spit out much water either. As soon as I pull it out for the year, I will take a look at the impeller to see if it is still good. I suspect it is okay (and yours is too) as my engine has a high temperature warning. I have run all summer - fast and slow for long periods of time - and never had it go off, so I don't think it is getting hot. I am guessing it is normal not to get a steady stream out the back, but I am not sure.
@@mbrenengen Thanks Matthew. I actually took out the thermostat today and got a steady stream so that answered my question. The tell tale is after the thermostat on my motor so it needs to get up to Temp before I will see any kind of stream
i was in lake last saturday starting but only go to revers dont go to forward end try to starting in home dont wont star,oso i see by the fron in the lower unit leacks like grease ,bad water pump impeller cause problem to go forward thanx for answer
I did the same on my Nissan/Tohatsu 18 hp 2-stroke, manufactured in the early 90's. Renewed only the impeller, interestingly there were no seals, alignment studs were solid on the pump housing and pump had only 3 bolts. An easy job, but I just forgot to put back some geat linkage parts etc...took me extra 10 mins. Now it works great and squirts instantly :)
Thanks for posting this! I have the same engine and was about to tackle the impeller for the first time. Glad you showed the box and part number for the kit, as I was about to order just the impeller. This helps a lot.
Have a 1990 Nissan NS 40. Motor is overheating and water flow from impeller is weak. Going to try this as I have never replaced impeller over all these years. Will also replace the thermostat. Engine has been a champ for 30+ years. Want to milk it as long as I can. Thanks for posting the video. Helped me decide on a DIY vs. taking it in to a dealer for the work.
Thank you Matthew. I followed your video and replaced the impeller on my Tohatsu 50hp 2 Stroke TDMI. Couldn't have done it without your video. :0)
Great video. Just a suggestion: use a putty knife to remove those gaskets. That chisel might gouge the housing. This from watching my grandpa who was a jet mechanic and dad who was a factory mechanic work on things
No gasket between the lower pump housing and lower unit itself, just gaskets for the wear plate on this model. No silicone necessary either. Ideally, you would not want to reuse those roll pins but otherwise a very good job overall. For not having a service manual, you had pretty good instincts to not to over-tighten bolts on the aluminum housing as well as lubricating the impeller and drive shaft splines and orienting the impeller vanes correctly.
The once a year interval is overkill in most situations. If you're in harsher running in environments (think sand, mud, excessive vegetation) or you rack up excessive hours then it might not be a bad idea. They do dry rot over time. I'd be willing to bet that one had not been changed for a long time and was obviously still in pretty good condition. Usually when the pump is going out it will give you a little bit of a warning with a weaker stream at idle (assuming no blockages in the internal water passages or tubing).
Do keep up with lower unit oil changes though. If you get a leaky seal you can catch it (milkshake) before long-term damage is done to the lower unit.
You should be able to have that anti-cavitation plate re-welded fairly inexpensively. Be careful with that hydrofoil, those can break even a good anti-cavitation plate and you have a good bit of yours missing.
Replace the anode when about 50% gone.
The 40D was one of the best engines Tohatsu has ever produced.
I randomly found this while watching your Saab brake videos. Gotta love CZcams.
Great information. I have a 1700 Key West Sportsman. It came with the 40D tahasu outboard motor. The boat has been used continuously since new on the lower chesapeake bay. Thousands of hours. Still running well. Weekly fishing trips to the HRBT on 10gals of gas
Well done Matthew, few if any how to's actually show all the steps needed to R&R a lower unit start to finish no matter the need for removal great video!
Yep just the video I needed! Thanks!
Really nice video. Gave me the confidence to tackle mine, which is the same engine 😃
Great to hear. It is not hard. Let me know if you have questions.
Put the impeller on first with the key in. Then put cover on spin drive shaft clockwise little easier
Nice video mate. 👍
What size was the nail u used? The pin has a hole in the middle?
There's an o-ring seal that seal on the bottom plate that separates the gearbox from the water pump
Question regarding your Tohatsu - I'm trying to troubleshoot my used but new to me nissan 25 HP from the early 90's that doesn't seem to be peeing after startup. I've swapped my impeller/seals/cup but the motor still doesn't pee. Do you get stream on yours immediately after a cold start or does it need to warm up first?
Daniel. That is a really good question. I have been concerned about mine this year as it doesn't seem to spit out much water either. As soon as I pull it out for the year, I will take a look at the impeller to see if it is still good. I suspect it is okay (and yours is too) as my engine has a high temperature warning. I have run all summer - fast and slow for long periods of time - and never had it go off, so I don't think it is getting hot. I am guessing it is normal not to get a steady stream out the back, but I am not sure.
@@mbrenengen Thanks Matthew. I actually took out the thermostat today and got a steady stream so that answered my question. The tell tale is after the thermostat on my motor so it needs to get up to Temp before I will see any kind of stream
@@dpgfla Great information! Thanks.
The bloody pin! How did you get that back in? and, um, where can I buy a new one? :)
brianlichty Squish it a bit first.
Mine has a threaded rod instead of a pin
how test spark in my tohatsu 8hp help please thanx jesu
Jesus Montes What is the problem? No start or missing or running on fewer than 3 cylinders?
i was in lake last saturday starting but only go to revers dont go to forward end try to starting in home dont wont star,oso i see by the fron in the lower unit leacks like grease ,bad water pump impeller cause problem to go forward thanx for answer
Jesus Montes That sounds like a serious problem with the lower unit.
Matt did you drain the lower housing oil before you started?
Yes I did. If you don't it will run all over when you tip it sideways.
Actually, I don't think I did drain it until after when I did change the oil. The seals should keep the oil inside.
@@mbrenengen awesome thanks!
Where was the thermostat located? Was that hard to change?
@@Doorbelly I have not changed the thermostat, but I think it is up in the motor somewhere.
@@Doorbelly Thermostat is right on top of the head, very easy to access and change.