2 stroke mercury 25hp installing a new outboard water pump, impeller and coldstart

replacing an outboard water pump and impeller on a 1998 mercury 25hp 2 stroke outboard engine.
USA
pump kit (OEM) seen in this video
amzn.to/2teSs3p
or
amzn.to/2sJH5is
Canada
amzn.to/2sZ1sqJ

[@sparlin88]

I want to thank you for helping me solve a problem. I just bought my first outboard . A 1999 25hp mercury . Bought from a guy about 100 miles away . Went there and it fired right up and ran smooth . Paid him $1,200 and took it home . Put it on this boat I just bought also and started it up with no problems . Went to put it in gear and didn't go in forward or reverse. I called the guy complaining and was told its my problem basically. So got here on youtube and found your post on changing water pump so went out and found out his great mechanic he bragged about didn't put the locking pin back on the gear selector shaft . Its fixed now and my wife is son happy . We both believed we were ripped off by a guy with no conscience or heart . Just greed. Thanks so VERY MUCH !!!!! YOU ROCK !!!

[@partsbenttoys]

6 yr old vid, still useful and helping ppl get by. thank you, great video btw

[@upnort1842]

Thanks for the video! I like how you very clearly point out all the bolts and the retainer!

[@aaronm1375]

Thank you, excellent video. My nephews dry started my Mercury 25 when I wasn't around, and it was recommended I replace the impeller before taking it out on the water again. I was dreading it, but after watching this video I am confident I can handle it. And I was gracious to my nephews since they didn't know how bad dry starting is, but they do have strict instructions on what will happen if they ever dry start it again. Thank goodness one of them tattled to me, or I might have never known.

[@alexmillwood1433]

Thanks heaps mate I've just bought one of these after watching this I feel confident to do the job myself and learn a lot more about these great little motors cheers for saving me some cash to every little bit helps at the moment

[@bart2u]

I had no ideal where the release was for shifting linkage. Thankyou so much for making this vidio. The macanic wanted 1 and1/2 hour and up to $100 dollars for parts u saved me $400

[@darrylhenchie4765]

A brilliant tutorial. Thanks mate. Just purchased a dinghy with 99 Mercury 25 hp. You're video was a brilliant and timely find. I've subscribed😁

[@fredrikh9299]

Thank you for generously sharing your know-how and taking the time to make a very instructive video! Regards from Sweden.

[@TheRfleming]

You were very informative and you didn't talk to much.Thank you.

[@robertcook1065]

after watching your video a bunch of times I did replace water pump today and cured the problem. thanks

[@johnvyverberg3283]

Thanks for the tip on removing the clip for the shift linkage! I was puzzled by this until I saw the video. BTW, my engine is a 9.9 Belgian 2 stroke.

[@tomschwartz2811]

The water tube came out when I dropped the lower end. With it going so far up in the motor, it's not that easy to re-insert it. I took a 5/16" wooden dowel and put it into the lower tube end. It's a tight fit and makes it a lot easier to re-insert the tube. The straight end of the tube goes up.

[@521VX05]

Excellent video. Was a great help in getting our 2000 25 EH changed out this week. Only difficulty we had was the shifter wanting to change gears as we fed it up the tube when reinstalling the lower. Just took some trial and error.

[@ericbrown9835]

Excellent video. I'm not at all hesitant to now take on my impeller change out.

[@deanbowe4070]

Just used your video to change the impeller on my mariner motor, thanks!

[@cagleoutdoors6384]

This video saved me a ton of time thankyou your a life saver

[@JBOutdoors]

Thanks for a great walk through video. I've done a smaller 7.5 hp mercury and wanted to compare as I'm doing one on a similar motor to yours.

[@russwentz3957]

Thank you, thank you, thank you! Between diagrams and service manual, wasn't clear on the shift linkage. Very clear, well done video. Thank you for your time to pass it on.

[@classicbikerx3588]

Wow, so much harder than the bigger units due to shift linkage! Good vid

[@tandk86]

Great work! Mine is flowing water like I never seen with pressure

[@freddynews6478]

Excellent video and description narrative.

[@jackgunter3999]

Your video just saved my day!!! Thank you

[@mbeck3132]

Very well done I wonder if it’s the same for a 2002 model?

[@suzanveltre7015]

I was forced to choke down a Harris ad to watch this video. Seriously dude?

[@ShnitzlHaus]

……… 🤷‍♂️ I don’t choose the ads displayed.

[@DougLandry-ub4dg]

Thank you just did mine . Your video was a great help.

[@morgan4xl]

If you try to start the engine out of water with a new water pump you will destroy the rubber impellor in less than five seconds. A very old and worn pump will last somewhat longer but it is a horrible practice to ever start your engine out of water. I started a new pump on the trailer in the water but the boat wasn't quite far enough back to submerse the pump and after a few seconds with no water coming out of the pee hole I shut it off and backed in farther to submerse the pump and a very weak stream came out. I burned the rubber impellor almost instantly. Be sure the lower unit is plenty deep for the first time starting, the pump won't lift the water even if it is any distance above the water.

[@BladeRunner.43]

I thought I had the wrong impeller I'm like well that doesn't fit lol thanks for the vid

[@oilheating214]

Wow you make it look easy

[@jacksonjuergens597]

Thanks for the help good vid will subscribe

[@LeslieWorks]

A bolt just snapped off inside when trying to take the bottom off....now what?

[@LeslieWorks]

Got the other 3 off and it dropped, but the washer didn't come out 😂

[@viviendolavidafeliz]

Thanks for your video, I'm trying to get the extractor key for the tail of that same engine and I can't find it anywhere and many mechanics don't even have that key. Can you help me know where I can get that key?

[@jimfry5385]

nice video. one question. I saw that you didn't use the 4-bushings. how come? Thanks Jim

[@kenhart5259]

What's so important about the washer? Mine didn't have one

[@goneFishing-yx5zy]

I just did one today and notice water coming out of where the shift rod comes through the that gap right about the lower unit dose yours do the same

[@ericpigg2689]

Mercury's mess with my head with that weak stream when the engine is cold! First time I changed my impeller, I thought I did something wrong.

[@TheBagman1977]

Same

[@kylemanson3015]

Mine does this too. It has a small amount of water coming from the tell tale when it cold. The tell tale gets stronger as it warms up. Is this normal for these outboards?

[@wmkess]

@@kylemanson3015 It must be tapped into the actual cooling passages, so it is dependent on the thermostat opening. Most outboards have it on the bypass line so it has good flow at any temp and only varies with engine rpms.

[@coleman1994able]

I have this exact motor and mine does the same thing! I thought I might need a new impeller until seeing these comments and this video.

[@cupslinga]

Was told to check the thermostat is moving freely as well, at the water pump change times as these are responsible for overheating the powerhead when they jam shut 👍

[@georges947]

Thanks for the reply I'm thinking is good looks the same at the end of video it's been sitting since 2005 just picked it up and going though it. Thanks.

[@joeblowjohnny2297]

Everything is remove 4 bolt and shifting cable is remove but my 25 mercury foot still won't pull out . It's moving slightly but won't slide out . Even trying to slightly bang the foot with 2x4 . Slightly moving but won't pull out . What do I do ?

[@davidv7616]

Great detailed step by step thank you I just did mine today

[@JoshVanHoose]

Well done!

[@Dave-jc6ky]

Hi, Thanks for the informative video! We have a 1987 Mercury 2 stroke XD ELH outboard. I will need to get this done. I already have the kit. However while apart I also have a complete seal kit and need to get that done and change the prop and prop shaft seals too. There is a single, "plastic" perhaps nylon nut for propeller and I need to find out if it needs replaced each time the prop is removed. Hopefully someone knows the answer to that and if anyone knows of a video on replacing all the seals in this lower unit PLEASE let me know. Thanks!

[@RobertSigler-t8r]

Hey dude loved the video great help I’m not much of a mechanic. But I do have a problem hopefully you can get back to me. Put everything back I believe correctly except I do not have forward on my motor what did I do wrong?

[@huntmasterjames]

Do those reed valves got bad. I been having trouble keeping my 25 hp mercury running. Carb rebuilt. Replaced vacuum lines.. getting gas out of vacuum lines when suction applied. Any suggestions.

[@Ethan-tz4kp]

Does anyone know about how long this would take for someone whose never done it before with decent mechanic skills? Thanks, the video is awesome and giving me the confidence to maybe try myself!

[@jeffreyotten7020]

2 hours from start to finish. Did it yesterday.

[@RuXsel]

U remove those 4 big screws like it was nothing.. i have to turn into hulk just to turn those screws 🤣

[@rustybill8702]

This was the best instructional video I’ve ever watched. I wonder if you might tell me where you found the model # location? The serial # on my 25 hp 1994 mercury was easily found but not the model number.

[@30383]

If your motor only has a plate showing the serial number (older models), Mercury has a web site where you can put in the serial number and the year and model number will pop up! It was the only way I knew how to order the correct impeller. Great video, by thye way

[@enercaledonie8496]

Merci pour le partage de nouvelle caledonie 😉👍

[@badluk1]

Great video!! Thank you!! (And still scared to try it lol)

[@RubiconUnlimited]

this install is Water Tight! great vid

[@Dave-jc6ky]

My motor is a 1987 Mercury 2 stroke and requires an o-ring seal near the end of the driveshaft. It wasn't on mine and I'm wondering if it came off during removal of lower unit and remains inside of the driveshaft housing. Do you happen to know how to remove the driveshaft housing so I can check for the o-ring?

[@smallflipz2302]

I need help i cant get the shifter rod and the clip to line up!! Everything was put back the same

[@gardeningGTA]

I have the same motor but with electric start. I can start the engine. But the engine bogs out and stalls after I press the accelerator. Any tips , ideas what the issue might be ?

[@MrAndreisousa]

hi thanks so much for this video, if I do everything correctly and still no water coming out in that same spot, that means there is a blockage somewhere, any ideas how to fixed it? thanks in advance

[@ajfarr3369]

Should the water tube on my 2003 mercury 25 HP have a snug seal at the top end ? There is a lot of space at the top around the tube .

[@socalinhouse]

excellent video dude!

[@ShnitzlHaus]

Thanks!

[@dylandavis4074]

Do these 25hp models have a thermostat or should they be pumping water immediately when running?

[@ericremillard8335]

What is the point of the little washer on the shifter part? I changed mine but it didn't have 1. I bought it used tho so the owners before me might of lost it ?

[@jameswhitman2240]

Thank you for the very helpful video. Can you offer some additional guidance and some trouble shooting. I replaced the impeller on my 4 stroke Mercury 30HP of similar vintage to the motor you work on during video and followed the steps carefully. After I got the engine put back together with the new impeller and restarted the engine, it doesn't make water fully. There is just a bit of water coming out of the outflow and it looks like water is being pushed up from the lower unit but outside of the lower housing. It appears as though only some of the water is making it to the upper section. Where would you start to diagnose where I may have made a mistake?Thanks

[@Asys1985]

I changed impellar and mine is leaking water out from the area just above the water level. Alittle bit above the lower stream you have. Any idea what it can be? I get a stream up aswell and its alittle hot so you can atleast touch it without getting burned.

[@mauriciodiaz1310]

Why is it only trickling small amounts of water ? I have same motor except a 20 hp and its doing the same thing should i be concern please help me???

[@ShnitzlHaus]

It should have a thermostat so if it’s not up to operating temperature it will trickle out. Mine opens up when warm and has a solid stream. But being online and not in person I can’t tell forsure. I’m in fresh water so I don’t have bad corrosion

[@MrGabys91]

My water tube stayed inside, it didn't come off. The water tube seal (the rubber piece you referred to) stayed attached to the housing though. I have a 94 merc 25 hp 2 stroke. I didnt hear anything crack, everything came out smooth. Is mine just like that?

[@vdwalrw]

Great help thanks!

[@sewing1243]

The idiot engineer/designer or whoever in procurement decided those two SS machine screws holding the carb cover on should have hex heads, not Phillips head or allen key head, should have to go and remove every cover on every engine ever sold in that configuration and replace them with a user friendly screw. I found that a 5/16" Craftsmans nut driver, if really held tight against the head of that bolt will allow them to be removed. I didn't have a metric set of nut drivers so I can't say if an 8MM nut driver will work.

[@larryhauck3285]

Fantastic video!

[@jasongodmaire7552]

So I don't have to drop the oil in the foot. Good to know. Would have done it for no reason

[@samlancaster6767]

What is the hole in the lower unit just above the water line that’s shooting out water? I just replaced my water pump and noticed mine was doing that.

[@michaelfelices4669]

Hola buenas tardes, quería saber que sale los cables del baston o acelerador de ese mismo motor mercury 25 hp. Tengo el mismo motor pero no logro conseguirlos

[@williammorris9600]

shouldn’t it be spraying out water instead of just dripping?

[@ShnitzlHaus]

This has a thermostat. It drips until it gets some heat. Then it has a solid stream of water. I would be interested to hear from other owners if it’s similar I have not used the outboard much. I will likely inspect the thermostat

[@jonathanb9429]

Excellent video ! Thanks

[@liamwells7990]

Does the pin pass thru the spline

[@franciscorojas4631]

Can you show me where both ends of the linkage attach?

[@riverrivers250]

Can a totally broken water impeller cause the engine to lock up?? Since its right on the drive shaft,,,, cause mine was in pieces inside the water pump housing.

[@ShnitzlHaus]

Possible pulling by hand. Running….. I suppose

[@riverrivers250]

@@ShnitzlHaus okay… jus wanted ur opinion.. i changed my water pump and drove arnd for 2 hours full speed. Didnt die on me…. Everybody was telling me my motor is “finished” and “it wont run long” but idk…. Gonna go for another test drive

[@MichaelPop72]

Hello, is the process the same on a 2006 four stroke with same hp?

[@Dave-jc6ky]

HI, Our 25 hp 2 stroke is a 1987. It look similar in design though the part to disconnect shift shaft is a bit different. I understand on mine there is supposed to a washer on the shift shaft to you have to be careful not to lose when dropping the lower unit. Is there something that insures on yours the washer doesn't fall off inside the motor when you drop the lower unit?

[@connorjacob4339]

I think I lost mine and I haven't put it back together yet do you know what it's for

[@MrknuckleHD]

Video was very well done.

[@bryantoney3275]

Nice video!! Any idea what the other o-rings are for in the kit?

[@TheMentiply33]

Nice work got to do mine

[@marc-andreouellette18]

Il manque un tuyau au remontage ... bon montage vidéo 😉 sarcastique

[@justinallison9757]

What size s wrench do you need

[@socalinhouse]

Nice job dude.

[@papazoo1]

Nice detailed video, I just bought a boat with a 97 mercury 25 HP, and was concerned that I may have a bad water pump because it didn't have a good steady flow of water. It will go between a good steady stream to sputtering out just a small amount. I notice yours look the same, is this normal. I haven't put in water yet just using muffs. I was told it was service with new impeller, but was thinking about putting a new one in to be on the safe side.

[@ShnitzlHaus]

If you have a thermostat that will be a reason for the sputtering stream. I haven’t had allot of success with muffs as of now. Try a garbage can full of water, rev the engine slightly out of gear. It should warm up enough to make a constant stream. I doubt your impeller is shot, but it’s good to be cautious.

[@papazoo1]

Thanks you for responding, that as fast. That makes sense about the thermostat will try the container method also. Look Forward to viewing your other videos.

[@7377alexis]

Great video helped alot

[@JulietteNiner]

you know what that shift clip is called or where to get it? Cant believe mine broke. Thanks for the video

[@pit81590]

Looks like it might be called a LEVER-BACKPLATE. PART # 823862 on my motor.

[@pacman4568]

How hot should the water come out of the P hole. It is very hot on my engine

[@darrelladams9145]

130deg F as that is the temp the thermostat. It's a weird design as it is almost hot enough to burn you

[@iboats1]

during pulling down the lower unit came out with water tube(pipe). you just push it back? is there any seal at the top?

[@ShnitzlHaus]

Yes you can push it back up, o ring seal I believe. Then when installing the lower unit you want to make sure the tube engages the water pump.

[@lhoward8]

What would cause the impellers to shear off after the installation of a new water pump? Had mine replaced twice and impeller continues to shear... Motor begins to smoke a little, but water continues exit

[@iboats1]

@@lhoward8 underprasure chanel in water pump is blocked, and water pump is working properly

[@tonyfarr7397]

@@ShnitzlHaus my water tube came out when removing lower unit. There is just a hole on top - no seal ! There is space in the opening all around the water tube. How can this cool my engine? Should Ithere be a seal of some kind ?

[@georges947]

Your video is great ! The manual said nothing about removing that upper pin anyway water does come out but after about 2 minutes very hot ! Any idea what to do or is that normal? I'm new to these motors.

[@ShnitzlHaus]

It should be coming out as a strong stream when the thermostat opens, spitting to light stream when closed. Hard to say on temp as it should be hot. If you are in salt water you might have corrosion and build up in the water passages.

[@rockyvoltzdt2376]

why is it that theres enormoust oil is coming out in the water what might br the reason.

[@ShnitzlHaus]

Because two stroke.

[@randallwharrell]

Great video. At 3:36 you talk about that washer. What is the function of that washer? Also, when I dropped my lower unit, the drive rod and spline rod came all the way out. But the other rod (I’m thinking it’s a pipe that uses water for cooling. Should it come out when removing the lower unit?

[@ShnitzlHaus]

I can’t recall the washer. If it supported the rubber when shifting on the upper head side (engine). If the pipe doesn’t come out that’s okay. When assembling it’s better to have the pipe in first because it’s near impossible to tell where it’s going when it’s installed on the pump first. And if it doesn’t engage the engine above you will not have cooling and will need to drop the lower unit again.

[@tonyfarr7397]

The washer fell out when you re o ed the lower u it ! Look for it on your video

[@user-dj1gl5ix3m]

I just bought my motor, its used, and there wasn't a Shift Linage washer. Is it a Critical part?

[@John-of5sh]

I am just now watching this video which is why it took 3 months to reply. YES! You need that washer. I haven't unbolted my lower unit yet because I am waiting on the kit. I decided to go ahead and start the unbolting process and the first thing I noticed was I couldn't tilt the motor. The washer at the top of the shaft is what releases the catch that locks the motor down. You have to remove the rod (?) on the tilt mechanism that locks your motor down to tilt the motor back. If you don't install the washer sooner or later you are going to smack something, like an underwater rock or stump, and possibly do some serious dammage to your motor. With the washer installed the lock mechanism releases from the tilt lock allowing the motor to flip up instead of absorbing the entire impact. I am not good at explainiung things. Just take my word for it, if the washer didn't need to be there Mercury wouldn't have put it there.

[@dakotaboysnomadicadventures]

I have the same motor.. Is it necessary to drain the lower unit oil first before dropping it?

[@ShnitzlHaus]

No the lower unit holds the oil internally. Oil seals and the drain and fill keep the oil in.

[@dakotaboysnomadicadventures]

@@ShnitzlHaus right on thanks..

[@hc243102]

was that blue thread locker that you used on the pump housing bolts?

[@ShnitzlHaus]

Tend to use blue on everything. Good sealant also helps to stop oxidation.

[@louisdickerson5500]

Would this be the same process on a 1989 25 horse merc?

[@ct1762]

yes, just the shift linkage is different with one screw holding it together. unscrew it and pull out

[@marcbtz9499]

After I did this on my 8hp 1996 mercury I can't switch to forward when turning the handle. What do I do? Great video

[@ct1762]

something is not connected properly. does it go into neutral/reverse? look on the starboard side shift cam linkages and make sure they aren't binding up.

[@shanester8712]

A local marinia changed the impeller for me last year. And it wouldn't go into reverse. Or unlock the trim latch in forward. Was told they didn't put the important washer back on told of shift rod. Guess I'll have to fix it myself now that I know how

[@gregh2880]

Great video. Question: I noted that the water from the "tell-tale" was not a stream, but rather a spitting volume. Does the volume of water from the tell-tale increase when the motor warms up, or is this all that comes out?

[@ShnitzlHaus]

thank you Greg, I have noticed this on other Mercury 25hp from this vintage, on mine in particular it will be a constant spitting on idle and then smoothens out some, not sure if its just purging the air out from the initial start. when in gear its a solid stream. I was monitoring this when I took it out last but forgot to note its idle stream. I found this odd but some mechanics assured me its fine. I would be curious if any other viewers have input.

[@gregh2880]

More info from me: I just replaced the impeller on my 1998 25 Merc and indeed when first started, there is a very light dribble from the tell-tale. Within a minute, there's a solid steady race-horse pee stream coming out, presumable when the T-stat opens - ?

[@ShnitzlHaus]

I took the boat out last week. aside form a bad spark plug leaving me running on one cylinder, I did note the tell-tale. firstly I do have a thermostat originally I thought my engine did not, not certain why maybe because its so small! when the engine warms the dribble turns into a full strong stream. all is well :)

[@johnropeleski6006]

this is normal,when the thermostat fully opens,you will see a full stream of water coming out of the tell -tale.

[@mspaz481]

very informative thanks.

[@lindseygoodwin8757]

I'm having a hard time getting the lower unit to line back up right! i was wondering if you had any suggestions? thanks

[@ShnitzlHaus]

you are trying to engage 4 different components here, the pump housing into to the tube that feeds the water to the engine. the shift linkage to engage the shift arm, the drive shaft to engage the engine splines and lastly the dowel pins to align the lower unit to the midsection. I believe most difficulty comes from getting the drive shaft to engage the engine splines, to help with this put the lower unit in gear and spin the propeller slowly by hand to help get the splines lined up, or slightly pull the pull start (more awkward). it will take some doing to get them to slide together but when they do, it should be smooth and not forced.

[@dhajek2754]

i had the same problem. I tapped it with a 2X4

[@chyrice3787]

I have the same exact mercuryafter watching ur motor run it shakes, mine does the same exact thing. Why do they shake at idle??

[@coleman1994able]

I can’t tell you why but mine does exactly as this motor does as well. Same with the water stream being weak on cold start. Even with a new Impeller

[@VærdAtSe]

@@coleman1994able hi. Does your coolant steam varying in strength? Mine is like going on and off when idling in a tub.. also it feels quite hot? Best regards

[@coleman1994able]

RH only on Initial start up. Once Iv given the motor some throttle the stream opens up. Sometimes it takes a few seconds during winter. And if I shut down the unit a fish a while the stream will again start out weak and vary in the output Briefly.

[@coleman1994able]

RH if yours is getting hot I’d say you need a new impeller maybe a thermostat as well. But I’d bet impeller.

[@ajfarr3369]

I,m afraid water will just come out around all that space and not properly cool the engine

[@christophermeyers9095]

Do you have to empty the oil?

[@ShnitzlHaus]

No you do not

[@mattmuch1]

Nice vid. Thank you. Can you tell me where you got the bent ratcheting wrench? I've looked everywhere for that exact tool.

[@ShnitzlHaus]

Yes the store is princess auto in Canada, they ship world wide. It is there professional brand “pro point” I can try linking later.

[@mattmuch1]

@@ShnitzlHaushey thanks for the quick response... that would be great.

[@ShnitzlHaus]

I cannot find them online. I wonder if I gave you the product number if you can call in and buy. I think they still stock them maybe just not listed online.

[@mattmuch1]

@@ShnitzlHaus yes. I was looking as well to no avail. If you still have the # that would be great I'll give them a call. Thanks for the time and efforts

[@SIMPLEARKANSAN]

ShnitzlHaus do you still have the kit product number?

[@sammymenfi1909]

Great vid