Yamaha 30hp 2 stroke impeller replacement...

[Yoodles82]

Hi Guys,

So i got around to borrowing my brothers boat, and he's given it to me in less than perfect condition. The telltale stream isn't coming out, and despite trying to unclog it with wire and blowing it out with the air compressor, there's still nothing coming out.

He has never replaced the impeller since he bought it over 5 yrs ago, so thats what i'm betting on.

So, tonight i've got a mate around to help me pull it apart.

I'm after some model specific tips for impeller replacement. Its a Yamaha 30HMH model 2stroke 30CV.

Has anyone done a replacement before and got any tips so i dont stuff it up? Like whether i have to be in a particular gear and what grease to use etc?

Thanks

Nat

[aussie123]

Impellors are generally done out of gear.

Depending on the type of motor the gear shaft will be joined somewhere between the lever and the impellor housing but most times it is just below the powerhead area.

Knock the pin out and seperate the shaft.

Undo the bolts down near the cav plate and wiggle the leg off.

You will see a set of probably 3 small bolts around the shaft so remove them and the housing and you will see the impeller.

TAKE NOTE WHICH WAY THE FINS ARE BENT ON THE IMPELLER AS THE NEW ONE AS TO GO BACK IN THE SAME WAY.

Once you slip out the old impeller there is a stainless plate underneath.

If it is worn with groove marks you will need a full kit and not just an impeller.

Also before removal check all blades are on the impeller,if any are missing you need to find them and make sure the are not up inside the engine somewhere.

Also check both sides of the impeller housing for any fine cracks.

I also get new gaskets every time so now all you have to do is put it all back together.

Make sure the water pipe from the leg slips into the water pipe up inside the motor otherwise you will have issues.

Do up all the bolts and rejoin the gear shaft and your done.

Nice easy job that should take you about half hour all up.

[ipk18]

Have a look at you tube how I done mine just watch a bit pause it do what is says then play a bit more took me about a hour first time

[Yoodles82]

Cheers aussie - i figured its worth a shot to have a go myself before i spend big bucks in a workshop.

[Yoodles82]

Have a look at you tube how I done mine just watch a bit pause it do what is says then play a bit more took me about a hour first time

Got a link IPK?

[ipk18]

Have a look at you tube how I done mine just watch a bit pause it do what is says then play a bit more took me about a hour first time

Got a link IPK?

Can't on iPad ATM but just search In YouTube james town tv should be the first one with a chick it's for a 25 hp but all about the same

[Yoodles82]

Thanks, watching now :-)

[Yoodles82]

Well after reading the manual and watching about 10 youtube vids on the process...i'm halfway through replacing the impeller.

And this afternoons efforts confirmed the problem.

No telltale stream was DEFINATELY due to a busted impeller, with pretty much nothing left of it, as seen in the pics. I'll now order the parts and install a newby.

Who knows a good yamaha parts dealer in brisbane???

Hope these pics encourage others to have a go at simple maintenence...if i can do it...you certainly can!!!

Thanks

Nat

Lower arm taken off

Impeller housing around the drive shaft

What's left of the impeller around the drive shaft

Impeller housing

Housing and impeller removed

Bits of impeller under the bottom plate

[aussie123]

That flat wear plate looks like it is grooved so a water pump kit may be your best option.

You should get a new set of seals,flat lower wear plate,top cup(stainless cup inside upper housing) and an impeller in a full kit.

You also need to make sure no rubber bits are up inside the motor now as that impeller is about the worst I have ever seen.

If that was my motor I would be remove the tell tail hose from the motor and remove the thermostat so you can back blast water through the system with a hose to remove any rubber debris that may be up inside the motor.

For a couple of dollars extra order a new thermostat gasket as well if you do those extra checks.

[Derrilex]

She looks a bit neglected eh. I'd do a full kit for sure and x 2 with the thermostat. Stones Cnr are as good as any for yammy spares and Ive always found them really helpful with mechanical advice. May as well change the gear oil while your at it

[Yoodles82]

Thanks guys,

Yeah i plan on blowing out the system cause i'm sure there are some bits of the impeller still unaccounted for. And have already drained the gear oil.

Well my bro said he has not serviced it since he bought it....he is the king of neglect. "Why take care of what you've got when you can just buy a new one!"

[Ricko69]

Changing the gear oil while your on the job is good advice !!!! I would take it looking at the impeler

[aussie123]

Once the impellers all fitted grease that entire shaft before you fit it back in.

Pull the prop and clean behind it and grease the prop shaft as well and that is basically a full service done on the lower end.

If you're not sure on the easy way to refil the gearbox oil you fill from the bottom hole.

Keep squeezing the oil bottle and the chamber fills from the bottom up and pushing all the air out the top hole at the same time.

Once oil starts flowing out the top hole screw up the top one and then the bottom one.

So many people try and fill from the top hole and wonder why it takes hours to do or get very little oil in as there is an air lock inside the gearbox.

[jameshallam]

ur brother work for q build and live atr albany creek

[Yoodles82]

Once the impellers all fitted grease that entire shaft before you fit it back in.

Pull the prop and clean behind it and grease the prop shaft as well and that is basically a full service done on the lower end.

If you're not sure on the easy way to refil the gearbox oil you fill from the bottom hole.

Keep squeezing the oil bottle and the chamber fills from the bottom up and pushing all the air out the top hole at the same time.

Once oil starts flowing out the top hole screw up the top one and then the bottom one.

So many people try and fill from the top hole and wonder why it takes hours to do or get very little oil in as there is an air lock inside the gearbox.

Thanks mate - thats a great tip!

[Yoodles82]

Here's the next question....

Since all the blades on the old impeller were gone, how do i tell which direction to point the blades for the new impeller install????

Any ideas?

Thanks

Nat

[aussie123]

I think it should be anti-clockwise.

Slide the impeller down the shaft and make sure it slides over and locks onto the woodruff key.

Then slide the housing down till its sitting on top of the impeller.

Push down firmly on the housing and twist it anti-clockwise at the same time and it will bend the impeller tynes and slip onto the impeller.

Line up the bolt holes and do them all up.

[Yoodles82]

Thanks....going to stones cnr marine now.

[Yoodles82]

OK next question.

Impeller is fixed an lower unit put back on, with gear oil changed.

Now when i run it, i can't get a clean neutral moving from reverse gear to neutral - there is a noise (and i can only guess its because its not fully in gear). Forward gear has no noise. Forward to neutral seems fine. Reverse has no noise. But reverse to neutral doesnt quite come back to normal.

Any thoughts?

Nat

[Yoodles82]

Nevermind, i've figured it out....I knocked it out of gear while i was putting the lower unit back on. Just had to take it off again and align the gears properly.

Posting some pics just for others in case they want to try their hand at it as well.

I’ve found you can never have too much information on this sort of thing.

Thanks very much for everyone’s help. Especially Aussie123!

Cheers

Nat

Starting from scratch...

Slide on the baseplate

Punch in the woodruff key

Slide on the impeller - lining up with the woodruff key

Slide over the houseing - turning the driveshaft clockwise

Screw it down

[Yoodles82]

Then insert the lower unit back in, aligning the driveshaft, water tube, and shift rod.

Screw in the four bolts to hold the lower unit on, and reconnect the shifter rod - paying attention to where it was sitting when you disassembled.

Now start her up and watch her peeeeeeee!!!! :-)

Lower unit bolts:

Shift rod connection

PEE!

[ellicat]

Unfortunately I am an expert in this area through several unwanted experiences...

On the gear rod that goes from the gears at the bottom to the top and eventually to the gear cable (assuming forward controls here) you will find a join where you can adjust the tightness etc - like the brake cables on a push bike. On the Force it is just a long nut that both ends thread into.

(This is harder to explain than I thought :blush: )

You will find this process much easier if there are two of you.

Have someone operating the controls and make small changes to the adjustment and then spin the prop and test when you are going into/out of gear.

My experience is limited to Mercs/Force so the Yammy may be different but should be similar.

If not then maybe Lance will be along with a (no doubt) better and fuller description. :blush:

[ellicat]

Wish I had started my reply a lot later :pinch:

That seriously hurt my head

Good to see all is well.

[aussie123]

lol ellicat,you did well (I think :whistle: )

Sorry Nat but somehow I missed your post earlier.

I would have only suggested you drop the leg again and re align it.

It is a simple and common problem that you had.

Great set of pics you have posted up and they should be a great help to others who want to try and replace their own water pump systems.

All motors are basically the same so they will come in handy for a lot of people.

Anyway glad its all working sweet now.

Lance

[Eug]

good little tutorial nat!

[Yoodles82]

Wish I had started my reply a lot later :pinch:

That seriously hurt my head

Good to see all is well.

Haha, yeah sorry - the pics took a while to upload and you got in as i was writing :-)

Good though - i'm sure someone will have this problem again!

[Yoodles82]

lol ellicat,you did well (I think :whistle: )

Sorry Nat but somehow I missed your post earlier.

I would have only suggested you drop the leg again and re align it.

It is a simple and common problem that you had.

Great set of pics you have posted up and they should be a great help to others who want to try and replace their own water pump systems.

All motors are basically the same so they will come in handy for a lot of people.

Anyway glad its all working sweet now.

Lance

Thanks for your help lance - invaluable advice :-)

[Woodlaz]

Thanks guys, this is an awesome thread. I have read a little bit about this stuff but have learnt a lot more from this single thread. Should be stickied or somethin and hopefully not lose its pictures in 3 months.

Excellent work guys, and THANKS.

Also, I have had a 15hp yammy 2-stroke (got it new) for about a year and a half now, only done about 8 hours or so and it's now time for its first service. The salesman told me (when i bought it), with the 1st service they change something to make it go a little faster once it has been run in (as well as the normal service). Is this true - if so what do they do?

From reading this thread I'm quite confident I can service the motor - just wanted to know if theres anything different they do for a first service. Is it worth trying to get a service manual?

Cheers

Glenn

[aussie123]

I personally would pay the dealer to do a first service on a new motor.

From there on though I would do most of the servicing myself.

I don't know what he would be changing to make it go faster but they will check and tighten the head bolts and other bits and pieces that don't need doing after a first service.

If you have the proper manual you can do it all yourself but I think that very first service is what makes a motor as reliable long term as it can be.

[Woodlaz]

Sweet. I will get the first one done by a pro (where do u live? :P ) hahaha. Your a good bloke for sharing your expertise/thoughts/advice. I will get it serviced at StonesCorner Marine as I have had good experiences with them in the past.

I can't remember what he told me but I think it had something to do with the carbie. I have had quite a few beers and sleeps since then not to mention I have trouble remembering what happened last week, let alone last year.

Thanks again to both you and the thread maker.

Cheers

Glenn

[jeff f]

hey all just did my yam 30 and found they aren't all the same.had me stuffed why the box wouldnt come off.

so after much swearing and confering with an expert(ellicat) i found a fifth bolt holding the gearbox onto the leg, it's hidden under the toe skeg plate recessed up into the housing and requires a narrow 3/8 or 1/4 drive tube socket in 12mm to get at it.

[Oliverm]

Reviving this old but great  thread that gave me confidence to strip down my water pump unit on my Yamaha cv30 engine after the tell tale wasn't pumping water when we tested it the other day.  

We ran the engine for maybe 5 minutes at 1/4 throttle and were feeling the leg to see how hot it got. It got fairly hot then there was a lot of smoke from the exhaust hole and it cut out. It restarted but kept stalling out so am worried it may have suffered significant damage. 

tonight I pulled the leg off. Some photos attached. I'm not experienced but there seemed to be a fair bit of soot and carbon build-up in the drive shaft and the top of the shaft appears discoloured with that purple colour from heat. The impeller is completely dead, plus the seal attaching the lower wear cover seems to be glued or melted when it should be a normal non glued seal. There was also a white plastic bush of some kind over the lower portion of the drive shaft I haven't seen on any videos? 

While I think I could replace the pump kit myself, checking for engine and gear drive damage from possible overheating is probably beyond me. Do the photos suggest an overheating issue?  Are there some simple tests I can do myself to check for problems? I haven't checked gear oil but was planning on replacing it when the pump is done.

Thanks!

[Drop Bear]

7 hours ago, Oliverm said:

While I think I could replace the pump kit myself, checking for engine and gear drive damage from possible overheating is probably beyond me. Do the photos suggest an overheating issue?  Are there some simple tests I can do myself to check for problems? I haven't checked gear oil but was planning on replacing it when the pump is done.

Was there water coming out while you tested it? If not it has probably over heated. You can over heat and not do horrible damage but only if you get lucky.

Is the motor seized? Does it start? Dont run it for more than a few seconds...

Black smoke can be caused by lots of things including over oiling or having old fuel or having not started it for ages but if it was running normally and then it started it is most likely that you cooked it. 

Over heating shouldn't affect the gear box. It is more the power unit that will be affected. 

 

[Oliverm]

1 hour ago, Drop Bear said:

Was there water coming out while you tested it? If not it has probably over heated. You can over heat and not do horrible damage but only if you get lucky.

Is the motor seized? Does it start? Dont run it for more than a few seconds...

Black smoke can be caused by lots of things including over oiling or having old fuel or having not started it for ages but if it was running normally and then it started it is most likely that you cooked it. 

Over heating shouldn't affect the gear box. It is more the power unit that will be affected. 

 

Thanks dropbear. 

There was only a dribble out the tell tale but there was water mixed in with the exhaust coming out of the hole on the leg. We were testing it on the water so as to rule out any muffler issue. 

I haven't tried to start it again but it turns over via the pull cord so pretty sure it hasn't seized. 

The smoke was gushing white and out the exhaust port so perhaps it was steam but it did start suddenly after it had been running for a while and then the motor cut out. We restarted it but it kept cutting out after a few seconds. Fuel was fresh and correct oil ratio (100:1). 

[Drop Bear]

3 minutes ago, Oliverm said:

Thanks dropbear. 

There was only a dribble out the tell tale but there was water mixed in with the exhaust coming out of the hole on the leg. We were testing it on the water so as to rule out any muffler issue. 

I haven't tried to start it again but it turns over via the pull cord so pretty sure it hasn't seized. 

The smoke was gushing white and out the exhaust port so perhaps it was steam but it did start suddenly after it had been running for a while and then the motor cut out. We restarted it but it kept cutting out after a few seconds. Fuel was fresh and correct oil ratio (100:1). 

Sounds bad but if it was me and I was on a budget i would try replacing the impeller and see if it runs and the tell tale works, you might be lucky. Then do a compression test and you will know more about it. 

When the motor stopped it may have been because it overheated. My layman's understanding of this is that everything expands and increases the fiction in the cylinder. You can easily end up with scoring in the bore and need new rings etc. If exhaust gets past the rings you loose a lot of power and engine is a lot less efficient. 

Good luck and let us know how you get on. 

Oh and there are loads of great videos about how to rebuild if you are time rich and cash poor. 

[Old Scaley]

20 minutes ago, Oliverm said:

Thanks dropbear. 

There was only a dribble out the tell tale but there was water mixed in with the exhaust coming out of the hole on the leg. We were testing it on the water so as to rule out any muffler issue. 

I haven't tried to start it again but it turns over via the pull cord so pretty sure it hasn't seized. 

The smoke was gushing white and out the exhaust port so perhaps it was steam but it did start suddenly after it had been running for a while and then the motor cut out. We restarted it but it kept cutting out after a few seconds. Fuel was fresh and correct oil ratio (100:1). 

Are you sure the correct oil ratio is 100:1?  Most yammies are 50:1 after the run in period.

[Drop Bear]

16 minutes ago, Old Scaley said:

Are you sure the correct oil ratio is 100:1?  Most yammies are 50:1 after the run in period.

my 2008 15hp was 100:1

 

[Old Scaley]

Made me go and check my operator manual for my 40 hp in case I had been doing it wrong all these years. Definitely 50:1 so it must be 30hp and under are 100:1?

[kmcrosby78]

I'm no mechanic but it would be worth running some thick mono line (about 80lb with a knot in it) through your tell-tale to check there aren't any wasp nests in there as this can be a problem, particularly over summer. I tick some wipper snipper chord in mine when it is not in use to keep the bu99ers out.

[Oliverm]

I can't get a new pump kit locally and am too time poor and mechanically inept to be confident everything is ok, so will get a mechanic to look at it. Unfortunately my preferred mechanic can't do anything until 15 January.

thanks for your help - i'll post back with an update in a couple of weeks.