Impeller Change Mariner (Yamaha) 4 HP Outboard 

We just changed the impeller on our '98 Mariner 5hp. There were only 2 blades left on it! This video saved us time and money for more fishing trips! Thanks again!

Thanks for this video. It inspired me to sort out the impeller on my 1996 Mariner 3.3. New impeller arrived very quickly and I set to work. The first two bolts came unscrewed beautifully. The third, just above the propeller seemed to turn quite easily but then sheered off. Now there is nothing to do except take it to a workshop which has proper screw extraction kit and a supply of screws of the right material. Clearly this screw had effectively welded through electrolytic corrosion to the aluminium casing. Now I am stuck. Until this point the motor had been amazingly reliable and in the previous two weeks of daily use it started every time first pull.

Thank you sir!!!! You have saved us a lot of time and hassle!! We were puzzling over where the impellor was for ages and then we luckily found your video. Thank you thank you thank you!

This video was great. i got 1 my own, i got it free from a friend and the water pump was not working. and i'm new in boat motors, But hx to this guy, he made my day:D btw, it was my impeller that was destroyed

I wish I had seen this prior to changing the impeller on my 5hp tohatsu. tohatsu impeller blades are straight and I needed to have the blades bent to the side to fit back into the pump. the trick I used was to cut the lock out of a zip tie and us it like a belt clamp. as soon as it started to slide in the pump I was able to remove the zip tie and push the pump together the rest of the way. I only say this to maybe be helpful to others attempting this repair for the first time. useful video.

Great instructional video! I was able to change the impeller in my Yamaha 2009 4HP. Thanks again.

I have a Yamaha 4hp -83 that looks exactly the same. All parts are just like in this one! :D

thanks save me a lot of experimenting and worked well, impeller shot to bits, now need a new one

Thank you very much for posting this video,i did the job in no time,,,A plussssss

thanks for an excellent video - followed to the letter and had great success. Once again thanks.

Thank you for your help. I have now replaced the impeller on my Mariner 4HP I got informasjonnen I needed from your video Greeting from Haugesund Norway Tore

Excellent tutorial, thanks for making this.

Thank you for making this video!

thanks for this instructional video, helped a lot!

Reliable when working. No I can't complain but it's been letting me down lately so I have just stripped the carb tonight actually, blew it all out and it started the best yet. I will post the procedure on here within a few days. Thanks.

Thanks, really great explenation!!

Good video - I've got a Yam 15hp so the procedure looks similar. Mine's a 1998 with about 3 hours use - bought it with a boat and only used it once - I'm now having to strip everything and grease it all etc.

Brilliant! Thank you very much.

Brilliant thanks man

How can you tell what yr your motor is on these outboards i need to order parts but dont know year of mine?

thanks buddy, very good and exactly what I was looking for! you will be hated by the boat mechanics around the world......taking all this money out of their pockets!

i watched youre video after i changed the impeller , you done it right to hahaha

Nice video Sir! thanks! Dave

Good video....thanks

While changing the impeller, that little gear clam that's not suppose to fall off - fell off. It is shaped like a 1/4 circle (so to direct the gear rod in or out). Does anyone know which direction it goes; to send the gear rod further or closer to the shift rod???

Excellent video. I am hoping to replace the impeller in a 5 hp Suzuki I have, and I suspect it's design will be very similar to the Mariner in this video

great video. having slight difficulties re assembling my outboard. I have the slightly later version off this outboard and the clamp for the gear shift rod came completely off. also is it a two part clamp because mine only appears to be one half?!?! thanks

all you efforts to assist me will be appreciated.

Yes, I think you're right. Cheers

No, you don't have to drain the oil from the gearbox. The impellor unit comes off with the gearbox. If your engine's overheating check the main waterways. I can't remember but I think it runs up the tube from the impellor, round the block and back down the central leg.

@drsyn123 Thanks for taking the time to help. Where i live there is no a marine shop of any kind, can I use an auto product as a gear lube for my outboard?

is the gears the same for the Yamaha 4hp 4 stroke as it is for the mariner 4hp 2 stroke.

thanks dude- very educative- loved it- i have 4 hp 2 stroke yamaha outboard and did exactly the way u dictated. But sorry to say, that the impeller was perfect, but the water pipe that follows the impeller towards seems leaking. Could you guide as to how do i remove that water pipe for replacement? For information, you see, i have a very poor pee from the exit.PLS SEE NEXT POST

thanks for video i have this outboard but i don't know what specifications have original propeller. mine is 7 1/2x7, standard for yamaha

If the shaft is still in place in the engine it must be stuck in the splines somehow. Try clamping the shaft with molegrips and tapping them downwards with a hammer. Good luck Mick

Water is quite hot, and i thought that it was the fault of the impeller, but it seems perfect. I later fed gravity water from a bottle and saw that water also leaked from the open up lower part as shown in your illustration, you can say that 50% came from the actual exit, and the other 50 % came sliding down from the bottom cover which i had opened. Possibly as i could not see deep inside the whole housing, i suppose the pipe is leaking that leads to the impeller.

It's a long time ago now but I seem to remember the pipe came off with the lower unit. If it does, try flushing it with water to see if there's a leak. I'm guessing the main water return goes out down the leg / exhaust. don't know if a small hose up the tell tail hole would tell you anything. Might be worth a try.

@jacksonfearns If it is a flat plate with 2 grooves in it, and a hole in the middle of the grooves, then it is a two piece bit. Maybe the other half has fallen inside? I can only see a 1 piece plate working if it has holes for the rods to go into, and there is some sort of split in the holes that closes up when you tighten the bolt, but I'm only guessing Regards Mick

@drsyn123 well the lower part comes right out, i was just confused, because i know forward is at the highest point. but if it goes down to neutral and i pull it back up to forward, i would think the rod would come right out, is there a way to get it to stay inside the lower unit?

@northshoreliguy . Can you see up the hole? is it clear. Is the cooling pipe in line. I can only think of doing what you are doing. i.e. turning the flywheel as you insert it. Good luck

I'm guessing you'll have to strip both parts out then try & get them welded back together. The lower bit of the rod usually just pulls out of the gearbox, so you might need to grip it with something then wack it upwards

I also tried to fix a pipe and blow from end and hold the other end, but air seems to leaks, - regards.perhaps you can guide me. Many thanks in advance

How about changing the Thermstrat on this motor? I think it on top left side. Any video on it? thanks

@Airshootingpractice the pee hole is in the top part just off centre just behind the main leg on the LH side when viewed from in the boat. If the impellors OK & the pipes not blocked a stream of hot water will come out of this.

what size and type of propeller does this motor have? I got ahold of one but it didnt come with a prop and I cant find the schematic for it anywhere

do you have to drain the oil out of the motor first. i have 4hp mercury 4 stroke and it over heats at full speed. but it still pumps water can you help

@Airshootingpractice Thats all I use in my classic outboards, just use 80-90 weight gear oil

Cheers

My Gear shaft is stuck in forward on the lower unit,

audio not audible which way do you spin the drive shaft as you slide the water pump housing down over the impeller ?

@Airshootingpractice I think marine grade gearbox oil has some sort of water "repelant?" or something in it. You should be able to get it from the web OK. Failing that if you changed the oil more frequently that might be OK

so my impeler is in good shape but my "telltale" still doesnt seem to be peeing out water, i have a 1988 4hp yamaha model 2stroke and i believe my water pipe might be cracked or has a hole in it right below the engine, it could also be clogged, how would i go about fixing that? thanks -Kurt

I'm afraid I don't know. I just called in to a local chandliers and luckily they had one. I'd noticed a few on ebay before that though. Cheers Mick B

does anyone know how to remove the piece behind the propeller at 1:16 to get access to the gearbox.I removed the propeller and took out both bolts but it dosent seem to be coming out.plz respond

Anyone know what i should do next,My yam 4 is not pumping water,had it to bits totest imppeler and it works fine. What next.

Hello there. I also have a Mariner 5 Hp. How can I test if the impeller is working? Where is the pee hole? And where can I check the oil level??? Thanks a lot.

Great video, but what's the impeller id number? I've got the same motor as you, but I don't know which impeller to buy. Any help would be appreciated!

Remove the 2 bolts and tap a screwdriver in the joint. Do it carefully from both sides.

@dyanemaniac no some mariners were made by yamaha and some are made by mercury because origionally, yamaha made mariner and then mercury bought mariner from yamaha

@Y0B0YCHRIS well, if so than mercury, yamaha and mariner would be the same. I have changed the impellor of my yamaha 4 today and this looked EXACTLY the same. so i do think yamaha = mariner

@Motorfordtoyota actually i have the same motor as him and mine has the yamaha symbol on the block because yamaha USED TO make mariner and then mercury

gee I hope it works on my 2000 merc 3.3. Shouldn't be much different.

Try blasting water throgh the water intake. You might have a blockage somewhere.

hey, i was wondering if you could tell me how to change the shift rod, i havea 5hp mariner.

I have the 3.3 hp model. Refitting this assembly is a nightmare.

i thought mercury made marnier not yamaha?

Dolls house lol :)

not sure how to dismantle the pipe, it's a long time ago now. Try this site crowleymarine com