Reply
 
Thread Tools Search this Thread
 
Old 08 August 2019, 14:20   #1
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
That old Change your impeller every year debate

Got my Brothers boat ready for him to go boating in. He does nothing to it and I don't think he has started it in over a year. He/We have owned the boat over 6 years and it has never had a new impeller. Not sure how long the one in it had been in before we bought the boat.

I Charged the battery and it started after about 4 attempts. Petrol in tank very old.

It seems to run ok and pumps water like a trojan .




Makes you think !
__________________

__________________
Bigplumbs is offline   Reply With Quote
Old 08 August 2019, 15:03   #2
Member
 
The Gurnard's Avatar
 
Country: UK - Scotland
Town: Stirling
Boat name: The Gurnard
Make: Quicksilver
Length: 4m +
Engine: mariner 25hp 2s
Join Date: Jul 2013
Posts: 1,274
I am no expert Big Plumbs but would imagine the impeller is like everything..if you dont use the boat much..it will last for years. I do my own servicing and check my impellers every winter but only replace them when I think they require replacing.

Example my 6HP Yamaha Four stroke averages around 200 hours per year. I check the impeller every winter and decided to change it after three years of use..approx 600 hours of running. It was still in reasonable conditions but the ends of the blades were wearing flat and it was starting to loose its spring feeling when I bent them..if that makes sense.

So yes..you are correct they could be fine..but if it was my OB ..I would at least check their condition. Simply because if they fail at sea..(and you have no idea what shape they are in ?) ..they could cause a loss of life. If not yours or your brothers ..someone elses if the RNLI are attending to your problem and someone else gets into serious trouble. Admittedly .. very unlikely .. but not something I could live with if it happened to me .. simply because I ignored checking a vital part of the engine that does wear out.

Does my reply make you think ?

PS..I don't replace my plugs every year either..I keep them going until I think they are done..but I check them regular too ..and carry a spare set on the boat
__________________

__________________
The Gurnard is offline   Reply With Quote
Old 08 August 2019, 15:14   #3
Member
 
Country: UK - England
Boat name: Bluefin
Make: Ribcraft
Length: 5m +
Engine: 150hp
MMSI: Ex Directory
Join Date: Oct 2015
Posts: 263
Quote:
Originally Posted by Bigplumbs View Post


Makes you think !

Certainly, modern merc 4 strokes are impellor change every 3 years or every 300 hours and TBH I have never changed an impeller as part of an annual service, but I do inspect it every year ............

At 6 years you really need to have a good inspection for the rubber cracking at the root of the vanes ...........
__________________
gpsguru is offline   Reply With Quote
Old 08 August 2019, 15:42   #4
Member
 
Country: UK - England
Length: 3m +
Join Date: Sep 2008
Posts: 2,572
Quote:
Originally Posted by Bigplumbs View Post
It seems to run ok and pumps water like a trojan .

Makes you think !
I'm thinking:

- why would someone think it would have failed in storage.
- how long will it be till a vein tears off and stops pumping properly.
- when a vein tears off will little bits of the rubber break off and block up the water channels
- if it was as simple as failing when testing in a tank rather than underway then people wouldn't replace routinely
__________________
ShinyShoe is offline   Reply With Quote
Old 08 August 2019, 16:31   #5
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
Answers below in red

Quote:
Originally Posted by ShinyShoe View Post
I'm thinking:

- why would someone think it would have failed in storage. They think the Rubber holds its bent position
- how long will it be till a vein tears off and stops pumping properly. Who Knows
- when a vein tears off will little bits of the rubber break off and block up the water channels Could do like all the other rubbish that is sucked into the raw water intake
- if it was as simple as failing when testing in a tank rather than underway then people wouldn't replace routinely Many don't replace routinely
__________________
Bigplumbs is offline   Reply With Quote
Old 08 August 2019, 16:33   #6
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
Quote:
Originally Posted by The Gurnard View Post
I am no expert Big Plumbs but would imagine the impeller is like everything..if you dont use the boat much..it will last for years. I do my own servicing and check my impellers every winter but only replace them when I think they require replacing.

Example my 6HP Yamaha Four stroke averages around 200 hours per year. I check the impeller every winter and decided to change it after three years of use..approx 600 hours of running. It was still in reasonable conditions but the ends of the blades were wearing flat and it was starting to loose its spring feeling when I bent them..if that makes sense.

So yes..you are correct they could be fine..but if it was my OB ..I would at least check their condition. Simply because if they fail at sea..(and you have no idea what shape they are in ?) ..they could cause a loss of life. If not yours or your brothers ..someone elses if the RNLI are attending to your problem and someone else gets into serious trouble. Admittedly .. very unlikely .. but not something I could live with if it happened to me .. simply because I ignored checking a vital part of the engine that does wear out.

Does my reply make you think ?

PS..I don't replace my plugs every year either..I keep them going until I think they are done..but I check them regular too ..and carry a spare set on the boat

Very wise words. I wonder however about the old adage if it ain't broke don't fix it


Or as I have herd it...... if it ain't broke don't break it
__________________
Bigplumbs is offline   Reply With Quote
Old 08 August 2019, 17:06   #7
Member
 
Country: UK - England
Length: 3m +
Join Date: Sep 2008
Posts: 2,572
Quote:
Originally Posted by Bigplumbs View Post
Very wise words. I wonder however about the old adage if it ain't broke don't fix it


Or as I have herd it...... if it ain't broke don't break it
Do you change oil in your car?
What about timing belts?
__________________
ShinyShoe is offline   Reply With Quote
Old 08 August 2019, 17:09   #8
Member
 
Country: UK - England
Town: East Anglia
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yamaha 15Hp 2-stroke
Join Date: Nov 2007
Posts: 5,320
I'm always a bit nervous with any used new to me outboard re the impeller condition even if it pumps OK so as part of getting the outboard to a known position I'll change it using a genuine OE one. With the Yamaha 15 2-stroke I bought this year I put in the full kit with upper pump housing liner and lower plate so it starts off as new.

Now I've done this, with our low leisure use hours compared to Gurnard, I'll probably only drop the lower unit 2 yearly and replace the impeller then whatever the condition. For me it's not worth the trouble of just inspecting at such an interval but then leaving the old one in.
__________________
Fenlander is offline   Reply With Quote
Old 08 August 2019, 18:13   #9
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,073
Quote:
Originally Posted by gpsguru View Post
At 6 years you really need to have a good inspection for the rubber cracking at the root of the vanes ...........

If those leg bolts have been sitting for over 6 years Iíd be keen to check they will actually move when needed.

BP presumably your inlet has a ďgrillĒ on it to filter out the big bits that wonít make it through the passages. There is no guarantee the bits that break off will be small enough to cause you no problem.

FWIW - I donít religiously change impellers annually. I actually think many people donít. But with an engine of that age having been sitting doing nothing for a long time - I wonder why you would take the risk.
__________________
Poly is offline   Reply With Quote
Old 09 August 2019, 00:17   #10
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
Quote:
Originally Posted by Poly View Post
If those leg bolts have been sitting for over 6 years I’d be keen to check they will actually move when needed.

BP presumably your inlet has a “grill” on it to filter out the big bits that won’t make it through the passages. There is no guarantee the bits that break off will be small enough to cause you no problem.

FWIW - I don’t religiously change impellers annually. I actually think many people don’t. But with an engine of that age having been sitting doing nothing for a long time - I wonder why you would take the risk.
Because it is pumping water very well and changing it is unnecessary.

Why would you do something that does not need doing why would you take the risk of messing something up when you pull it to pieces. Always a risk

There is theory and then their is facts and the evidence you see

If you have 10 boats + to look after and 12 engines you tend to only do what is necessary
__________________
Bigplumbs is offline   Reply With Quote
Old 09 August 2019, 00:47   #11
Member
 
Country: Germany
Town: StPetersburg Russia
Boat name: Ocean Devil
Make: Scorpion 8.6m
Length: 8m +
Engine: Yanmar 315hp
MMSI: 211579640
Join Date: Aug 2009
Posts: 618
RIBase
Send a message via Skype™ to Bushrider
I installed on all my outboards water pressure gauges .
Gave me during the year additional piece of mind .
__________________
6 cylinder diesel power
Bushrider is offline   Reply With Quote
Old 09 August 2019, 01:08   #12
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
Quote:
Originally Posted by Bushrider View Post
I installed on all my outboards water pressure gauges .
Gave me during the year additional piece of mind .
Now that is interesting where do you install those.... Any pictures
__________________
Bigplumbs is offline   Reply With Quote
Old 09 August 2019, 02:57   #13
Member
 
Country: UK - England
Town: East Anglia
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yamaha 15Hp 2-stroke
Join Date: Nov 2007
Posts: 5,320
>>>Why would you do something that does not need doing why would you take the risk of messing something up when you pull it to pieces.

>>>If those leg bolts have been sitting for over 6 years I’d be keen to check they will actually move when needed.


Yep that's the worry I'd consider BP... getting the lower unit off if it's been in place several years. Two problems... the lower unit bolts Poly mentions are inclined to snap off which is a whole world of pain and even worse the driveshaft splines can seize in the powerhead causing folks to employ all sorts of inventive but risky methods such as suspending the outboard upside down by the lower unit and hammering down on the underside of the power head.

This master bodger hammer jockey shows just how stuck they can get...

__________________
Fenlander is offline   Reply With Quote
Old 09 August 2019, 03:31   #14
Member
 
Fender's Avatar
 
Country: UK - England
Make: Zodiac
Length: under 3m
Engine: Scull
Join Date: Dec 2014
Posts: 407
Quote:
Originally Posted by Bigplumbs View Post
Because it is pumping water very well and changing it is unnecessary.

Why would you do something that does not need doing why would you take the risk of messing something up when you pull it to pieces. Always a risk

There is theory and then their is facts and the evidence you see

If you have 10 boats + to look after and 12 engines you tend to only do what is necessary
The engine manufactures schedule for impeller replacement is where I'd start and personally I always err on the side of caution
__________________
Fender is online now   Reply With Quote
Old 09 August 2019, 03:58   #15
Member
 
Country: UK - England
Town: Ipswich
Boat name: Click and Collect
Make: Valiant and Narwhal
Length: 4m +
Engine: Outboard
Join Date: Sep 2016
Posts: 1,107
Quote:
Originally Posted by Fender View Post
The engine manufactures schedule for impeller replacement is where I'd start and personally I always err on the side of caution
So ignoring reality and following that old Myth then.
__________________
Bigplumbs is offline   Reply With Quote
Old 09 August 2019, 04:16   #16
Member
 
Country: UK - England
Town: Waterlooville
Boat name: Tickler
Make: Halmatic P22
Length: 6m +
Engine: Inboard Diesel 140HP
MMSI: 235115642
Join Date: Sep 2015
Posts: 949
RIBase
Fender - don't rise to it.
__________________
GuyC is offline   Reply With Quote
Old 09 August 2019, 04:31   #17
Member
 
Fender's Avatar
 
Country: UK - England
Make: Zodiac
Length: under 3m
Engine: Scull
Join Date: Dec 2014
Posts: 407
Quote:
Originally Posted by GuyC View Post
Fender - don't rise to it.
lol, I've said my piece
Whatever people choose to do on the water is ultimately their prerogative, whether or not its the right thing is another matter
__________________
Fender is online now   Reply With Quote
Old 09 August 2019, 04:39   #18
Member
 
Dan Gurney's Avatar
 
Country: UK - England
Town: Bingley, West Yorks
Boat name: Iolar
Make: Redbay
Length: 6m +
Engine: Suzuki DF140
Join Date: Sep 2012
Posts: 1,030
Quote:
Originally Posted by Bigplumbs View Post
So ignoring reality and following that old Myth then.
What myth is that? The myth of preemptive maintenance?

To be honest I think the original premis of this post has value... particularly with reference to the 'old fuel' debate. Though even on that topic I'm not sure that the fact it runs in a bucket means that it will run well under load; personally I'd top it up with as much fresh as I could.

On the subject of preemptive maintenance, I would like to add my voice to the 'pro' side. The idea that you would just wait for something as crucial as an impeller to fail and not even check it is borderline irresponsible. And once you've got to the stage of checking it then for the relatively low cost of the part then you may as well replace it.

To be honest I find much of what the OP posts on rib.net to be inexplicable, inconsistent, and often wilfully contrarian. For someone with such a self-professed breadth and depth of knowledge on all types of motors, from remote control aircraft to ion drives and beyond, to have such a cavalier attitude to maintenance doesnt seem to me to quite ring true. But that is merely an opinion. He evidently takes great delight in proving people/manufacturers 'wrong' and exploding the 'myth' of duty lifecycles for engine parts; and if you share that passion the fill your boots. Just try not to stray too far from shore cos someone else will have to come and get you.
__________________
Dan Gurney is offline   Reply With Quote
Old 09 August 2019, 04:44   #19
Member
 
Dan Gurney's Avatar
 
Country: UK - England
Town: Bingley, West Yorks
Boat name: Iolar
Make: Redbay
Length: 6m +
Engine: Suzuki DF140
Join Date: Sep 2012
Posts: 1,030
Quote:
Originally Posted by Fender View Post
lol, I've said my piece
Whatever people choose to do on the water is ultimately their prerogative, whether or not its the right thing is another matter
Which is why I think it's important for other people to said their piece on these threads. Many folk new to boating use these boards as a reference (I did/do) so I think it's useful to highlight the fact that Mr Plumbs doesn't necessarily represent 'the orthodoxy' in all matters.
__________________
Dan Gurney is offline   Reply With Quote
Old 09 August 2019, 05:59   #20
Member
 
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: reiver 3.8/regal3760
Length: 10m +
Engine: 40hp 2st 2x6lp 315
Join Date: Jul 2009
Posts: 2,446
Quote:
Originally Posted by Bigplumbs View Post
Because it is pumping water very well and changing it is unnecessary.

How do you know it isnt necessary it could be ready to disintegrate any time?

Why would you do something that does not need doing why would you take the risk of messing something up when you pull it to pieces. Always a risk

If your that unsure of your abilities perhaps you should trust the work to someone more competent! Stripping the lower unit off regularly prevents it from siezing on and ensures you can fix it when you need to

There is theory and then their is facts and the evidence you see

If you have 10 boats + to look after and 12 engines you tend to only do what is necessary
Perhaps you should thin down your fleet so you can properly maintan what you have
__________________

__________________
beamishken is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT -5. The time now is 09:03.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.