waterpump impeller change

[ctswf]

1982 70hp Evinrude outboard model: e70elcnb

Hi,
It was brought to my attention the impeller should be changed periodically, :facepalm: Ive been running my motor since 2005 with no issues, but I suppose it's time to change out the impeller.

Sorry if this is a stupid question, but do I want to purchase anything other than a "Water Pump Repair Kit", for example what I found on this chart

Sierra Pump Kit w/Hsg. 18-3389

Johnson Water Pump Repair Kits - iboats

 

[Will Bark]

Re: waterpump impeller change

I would make sure you are ordering the repair kit WITH housing; you don't want to get in there and find out that you need a new housing. Good luck

 

[phillnjack2]

Re: waterpump impeller change

2005 and you aint changed the impeller !!!!!!!!!!!!!!!!!!!
you are very very lucky.

the impeller should be changed every year, and 18 months at the max to be safe.
they are only cheap and if changed each year you can then keep everything nice and free to do the removal of the gearbox and spline.

So its 8 years since the leg was off !!!!!!!!
That is crazy



phill

 

[riptide09]

Re: waterpump impeller change

The factory recommended replacement interval is 200 hours. For me that means every other year.

 

[bonz_d]

Re: waterpump impeller change

Those water pump kits come with 3 different pump housing pieces. Top plate, bottom plate and the round piece that the impellar rubs against. All of which will be or should be replaced along with the Oring and bushing seals.

Unless it has been really beat on I would just buy the rebuild kit w/o the housing. Again all the parts that will experience wear will be in the kit.

Some truely believe that the impellar should be replaced yearly. I think they are just wasting money. But then it's not my money they are spending.

 

[phillnjack2]

Re: waterpump impeller change

never seen 200 hours on an old engine manual.
its suggested to replace the impeller every season during the routine yearly maintainence.
this is a 1982 engine not a 2012 engine.
different type of rubber used on the old engines.

with two years of not even running the engine you can get a set on the impeller making it virtualy useless.

each season the leg should be taken off and greased on the spline and the leg checked for oil and the water pump checked for any score lines in the housing.
it would make perfect sense to change the impellor while this is all down, the small o-ring also needs to be changed if it has one
on the splined shaft at the top or bottom.

200 hours is not many hours, if people use an engine for 5 hours a day then its just 40 days ??? that is not 2 years.

most people change the impellor at the end of the season, i prefer to change during the end of winter just before new season starts
to make sure ihave every ready for the sunny times.

When putting in a new impellor use washing up liquid to make life easy and to help the impellor on its intial start up.

But 8 years and no impellor change is taking the p*&*s and can lead to having a frozen drive shaft that just dont come off.

with brand new e-tec engine it says 3 years or 300 hours before needing a service of any kind.
But this does not mean you dont change the impellor, impellors come under consumables and need to be atleast inspected.!!!!!

if i had a new e-tec it would still get a new impellor each year for sure.


phill

 

[ctswf]

Re: waterpump impeller change

yes, 8 years with no service to the lower unit other than changing the gear oil. Hours are not clocked but on average I use about 2 to 4 gallons of gas per trip, 3 to 10 trips per year if that give an idea of time I put on it... Usually drive 1 to 4 miles to a fishing hole and park it.

I read the service manual, I'm going to order the parts and give it a shot. I will order the water pump repair kit, along with the following the manual mentions, or try to find the equivalents:
OMC gasket sealing compound
OMC needle bearing grease
OMC adhesive M
OMC molly lube

phillnjack2,
"the small o-ring also needs to be changed if it has one on the splined shaft at the top or bottom."

The manual mentions changing the drive shaft o-ring, gear case grommet, and shift rod grommet... not sure if I should be trying to order these in advance or just pick them up local auto parts or west marine once I have them in my hand.

I'm also slightly confused about the the lower unit attaching back to the exhaust housing (if thats the correct terms). You just coat with OMC adhesive M or similar, no gasket is used right? I think it will be more clear to be once i pull it apart...which I wont be doing until I get the parts.

thanks

[edit] also, is there generally any wait time for any gasket sealers or anything? potentially can I get this done Saturday morning and be on the water that night?

 

[bonz_d]

Re: waterpump impeller change

Oring and grommets should all be in the rebuild kit. No sealant between the lower unit and exhaust housing/mid section/leg, whichever you decide to call it.

 

[the machinist]

Re: waterpump impeller change

You will see many different ideas on water pump impeller replacement. Personally for the average boater every year seems overkill. I have seen many that have gone 10 years & still functioning fine. Motor manufacturers & dealers want to insure that you don't come back on them for any liability, so yes, shorter replacement times. Plus they have no way of really knowing what envirenment the motor was ran in. Some boaters have no idea of even how to operate a boat, much less how the motor operates, as long has it has gas in the tank, a charged battery & someone did not forget to put the drain plug back in, they run it.

Just like buying insurance.

Yes, if it was my only power source & I was using it offshore 20+ miles, then that would be good insurance, but for the average boater on a lake, not the same situation at all.

What about the new Evinrude E-Tec where they say NO maintenance for 3 years or 300 hours? Spark plugs, water pump impellers, thermostats & gear oil are what they recommend changing at that time-frame. I run a E-Tec & inspect/replace the impeller depending the number of hours each year, which is between 60 & 100. But I have a kicker motor & do run offshore at times.

 

[phillnjack2]

Re: waterpump impeller change

The Evinrude e-tec engines dont need any engine service for 3 years.....yeah ive read that rubbish many times..

Now go check the small print about impellors,youl find if the engine siezes up due to a worn impellor
your warranty is then void!!!!
the impellor is deamed and termed as a consumable item, not an engine service item.

like an automobile having no oil voids the warranty as again its a consumable item..

its not just the rubber surface or vanes of the impellor to inspect carefully !!!
its also the Bond/glue used to bond the impellor to the hub.

Here is a pic of an impellor with great looking rubber vanes, but then look again, the hub bond failed....
..
this engine was pumping nothing at all due to this bad impellor..and it was genuine omc not aftermarket cheap one..

running an engine for 2 years is taking a big chance on the impellor side of things, plus its only a 20 minute job to replace and
cheap part to buy.

I have a 60hp triple and can easily change the impellor in under 20 minutes, it makes sense to change a cheap item.
plus by not inspecting it yearly you run the risk of having a frozen driveshaft that will never come out.

yes we've all seen engines that have lasted 20 years with even being touched, but ive also seen new engines fail fast.
i had one engine that was perfect, i replaced the impellor and 3 hours later the engine was dead.
a little bit of grit got in when running on the sea and destroyed the impellor and siezed the engine solid.


The O-ring on the drive shaft needs to be the right one,
Now when you do grease the drive shaft spline, wipe it first to clean everything off it, and DO NOT put grease on the
very top surface as it can cause an hydraulic lock in the future !!!!!!!!!!!!

The pipe that goes from lower unit to water intake pipe that will stay in the mid section needs to be absolutely dry.
if you put any grease on it it will move and not give a good seal.
i have put small tie wraps on them before now to stop them sliding up the pipe if its a problem !!!!!!!.

Do make sure when you tighten the water pump housing to tighten it all up nice and even and true.
The base plate if scratched bad with lines in it will need to be replaced to give correct pressure as well.
But you might be ok and not need this item.

personaly i would strip it down then get the parts, just incase you have a different pump to what your local
dealer thinks you have .



phill

 

[ctswf]

Re: waterpump impeller change

thanks guys, my local dealer (amazon.com) should have my parts here by Friday, I really appreciate the help. I may stop back in for more questions along the way.

nick

 

[riptide09]

Re: waterpump impeller change

Phill,

Don't want to argue with you. We can agree to disagree. The owners manual for my 2004 Johnson 115HP indicates the service interval for the water pump is every 200 hours or biannually. I average around 80 to 100 hours a year so for me it is every other year. I changed my water pump in August of 2010 and then again last September 2012. I have to say the water pump was functioning fine and when I took it apart it looked perfectly good and the rubber material on the impeller seemed fine (not hard and/or cracked).

If I was running out in the ocean I might be more diligent about changing it however as most of my boating is on lakes the worst that can happen to me is I have to ask a good Samaritan to tow me in.

One last comment, I use OEM rebuild kits. The OEM kits are not much more than aftermarket and I feel the quality and fit of the parts is superior.

 

[bonz_d]

Re: waterpump impeller change

I have a 60hp triple and can easily change the impellor in under 20 minutes, it makes sense to change a cheap item.
plus by not inspecting it yearly you run the risk of having a frozen driveshaft that will never come out.

i had one engine that was perfect, i replaced the impellor and 3 hours later the engine was dead.
a little bit of grit got in when running on the sea and destroyed the impellor and siezed the engine solid.

phill

Wow those triples must be a breeze. I have a twin and it takes me 20min just to get it off.

Your second statement here,,, What's your point? How has that got anything to do with a yearly inspection or change? New parts fail all the time!

I have a system that's been working for me for many years w/o a failure and it doesn't include changing the impellar yearly. So why change a good part that is working properly for a "new" part that may fail in 3 hrs?

 

[ctswf]

Re: waterpump impeller change

I finally got in to this, im having a hard time with the impeller key.

Is it at all possible the plastic "key" the kit comes with is not needed on the 1982 evinrude e70elcnb?


The old impeller I pulled off was notched to fit exactly over the drive pin and had no key(if im correct that the drive pin is the little 1/2 circle that keeps the impeller moving with the shaft)

The new impeller is slightly different in shape on the inside and seems like it makes sense to have a key, but I can't seem to get the key to fit right...

easier for me to draw it,
inside of impeller, old and new.


Also, is it correct that you have to jam the **** of out the impeller to fit it into the housing? I was not expecting to have to bend it into place to fit in like that

 

[ctswf]

Re: waterpump impeller change

ok im stupid, what I have is a Woodruff Key, do I at all need the plastic wedge key as well? I assume no.

 

[bonz_d]

Re: waterpump impeller change

There are 2 different types of impellars used on those depending on the year. The woodruff key is the old style. They will not interchange.
Ckeck to assure you have the right one. Sounds as if you don't.

Yes the vanes need to be bent and they all need to face the same direction.

 

[ctswf]

Re: waterpump impeller change

darn, sounds like the wrong part.
My 70hp motor head is stamped with e70elcnb, which is 1982.
The part I ordered does indicate on the box 1979-88 70-HP.

It was rebuild from a dealer when i bought it, I suppose the lower unit or drive shaft is older then?
This is what I ran in to when ordering new control cables, I matched the motor year, but the control box turned out to be older and didn't match the cables.

Do you or anyone have an idea how to look up the waterpump repair kit for this older style without knowing the year? Im going to bring the old part to west marine to match up but an idea would be nice.

thanks again,

EDIT:
oh i see on iboats waterpump lookup there arent many to choose from, ill go to west marine with those serial numbers and match up the part...

 

[ctswf]

Re: waterpump impeller change

One more question...

Here is a list of waterpump kits for my 1982 70HP
Johnson Water Pump Repair Kits - iboats

A) 1974-1978 / part 18-3388
B) 1979-1994 / part 18-3387
C) 1995-Up 18-3387


I originally bought B, the 1979-1994 kit which looks like this

The impeller key did not match, so now I ordered option A, 1974 to 1978. (I could not find it locally, it did not arrive in the mail yet).
This looks to be correct because it has a metal woodruff key like my shaft does.

and there really is no other option other than the wrong one I already got.

My question is this,
The old housing I pulled apart has the long "eleastic band like" gasket that fits in a grove (seen in the first kit). This second attempt I now ordered has a normal gasket

Does it seem right that this gasket will be used in place of the one that fits into a grove? and if so, is it bad to use gasket sealing compound on it since it will be bonding to a plastic housing I want to clean and reuse in the future.

 

[Watermann]

Re: waterpump impeller change

I didn't see anyone mention it but the last 70 rude I did was easiest to put the impeller in the housing first and be sure the vanes on your impeller are all trailing as the impeller turns clockwise on the drive shaft. It used the plastic key and was bear to get lined up right. I haven't seen a housing with a paper gasket, even my 1977 55 HP Johnny has the o ring. My 55 uses the woodruff key which was easy to line up. If you use gasket sealer use a light coat and be sure its the type that doesn't gets hard. Also I'm in the every other year impeller replacement crowd and have never had an issue. Sounds like the impeller replacement job has got you a bit on edge with bad luck on parts and horror stories, it's really a straight forward easy job. I would also replace the thermostat if I were you and the bypass grommet.

 

[ctswf]

Re: waterpump impeller change

Now all pulled apart I can see the job is easy.

Parts just arrived, everything looks like a match, the paper gasket is an exact match and covers the groove that would otherwise have the large flexable O-ring gasket, so ill use the paper one I suppose and cross my fingers, I already gunked up the matching gasket the first kit came with, which was the normal large O-ring type

I had read to always service the thermostat when pulling the leg off, is that because thermostat is located in the exhaust housing also? I think mine is located in the head.
Manual:
"On cross-flow V4 engines, thermostats and pressure valves are part of the exhaust housing adapter. Inline engines have a thermostat in the cylinder head"

what is the bypass grommet?

Nice nymph by the way, I wanted a sea nymph for a while before I settled on my starcraft a few months ago