Replacing impeller. How often? Good Maintenance Manual?

A forum for discussion of how to rig and tune your boat or kicker to achieve the best sailing performance.
Mark Prouty
Admiral
Posts: 1723
Joined: Mon Jan 19, 2004 8:52 am
Location: Madison, WI Former MacGregor 26X Owner

Replacing impeller. How often? Good Maintenance Manual?

Post by Mark Prouty »

Thought I'd fuel the debate. Plus the "Maintaining Modern Outboards" pdf link below seems pretty good.
Miami wrote:Actually, while all you guys with the Tohatsu 50Ds are here, I have a question.

How often do you change your water pump impeller?

Tohatsu/Nissan recommend every year, but that seems a pain if it's still pumping well.

What does everyone recommend, or do?
Maintaining Modern Outboards.
Opinions vary on regular impeller replacement; some mechanics say every two years and sooner if operating in silty water. Other say that unless you're chewing up the bottom with your lower unit your impeller will last many years and there's no point in replacing it until it starts to fail. (If you install a water pressure gauge you'll know if pump output is getting weaker.) I tend to favor the latter approach, as I've had motors go more than ten years with no water pump problems
whatsoever.
10 years! :o
User avatar
richandlori
Admiral
Posts: 1695
Joined: Wed Aug 18, 2004 8:08 pm
Location: Living Aboard in Morro Bay, CA
Contact:

Post by richandlori »

Timely post Mark, as my 2004 Honda 50 is at its one year old mark and I am digging around looking for my owners manual to see what it recommends that I do. I did buy the boat/motor used, but it only was in the water twice, so I can safely assume that all the hours on the motor were put there by me. However, I dont have an hr meter (want to add one) so I will make a SWAG (scientific wild ass guess) as apposed to a WAG (wild ass guess) and say that I have somewhere between 20-30 hrs on the motor tops.

My big dilemma is do I do the maintenance myself or tow it down to an authorized Honda dealer and pay the BIG bucks for them to perform relatively simple tasks?

Any advice on dealer vs Bozo? And should I just stick to the items that the manual recommends or do some additional items? This will be the first real maintenance other than checking the oil.

Yes, I have some tools and am marginally competentbut Im no mechanic, thats for sure.


Rich
Frank C

Post by Frank C »

After five years of neglect, there was nothing at all wrong with my impeller. But since I snapped off three of the water pump bolts in the effort to examine it, I spent a week f@rting around w/ it, and missed my planned cruise to Santa Cruz Is.

I undertook the effort because the indicator stream was weak - but turns out that was scum or such. I advise either an annual examination (so the bolts don't weld-in, or just skip it. Ten years seems fine to me if the stream is solid.

Never before heard of it, but I especially llike the idea of a water pressure gauge.

P.S. Rich - if you search on impeller, you'll find my tale of woe, which addresses some of the issues you've just raised. BTW, Suzuki's tachometer (included w/ 50 & 70 motors) is actually a multi-instrument. In addition to engine revs, it also tracks engine hours and provides warning lights.
User avatar
richandlori
Admiral
Posts: 1695
Joined: Wed Aug 18, 2004 8:08 pm
Location: Living Aboard in Morro Bay, CA
Contact:

Post by richandlori »

Frank, it IS your tale of woe that makes me want to take it into a dealer and not mess with it myself!!!!

Rich
User avatar
MSS
Deckhand
Posts: 36
Joined: Tue Nov 30, 2004 12:45 pm
Sailboat: MacGregor 26X
Location: Europe / Sweden 2002X - Honda 50EFI - MACX4868B202
Contact:

Post by MSS »

A friend of mine has a 1977 55hp Volvo Penta Outboard engine that his father bought new. Hes planning to change the impeller fore the first time after this season like he has planned for the last 15 years or so. The boat has been used almost every summer. The impeller is 28 years old. I dont recommend him to try but I think 30 years is possible with the same impeller, if you are lucky.

/Mattias

Sorry for bad spelling / grammar, I'm from Sweden...

Image
User avatar
Catigale
Site Admin
Posts: 10421
Joined: Fri Jun 11, 2004 5:59 pm
Sailboat: MacGregor 26X
Location: Admiral .............Catigale 2002X.......Lots of Harpoon Hobie 16 Skiffs....Island 17
Contact:

Post by Catigale »

THe mercury Bigfoot recommendation is 3 year replacement. I am a mostly fresh waterr sailor/motor use - not sure why this impacts replacement interval unless this is relevant to the thread (!) on threads.

Since I use the motor mostly on low revs Im thinking I stress the impeller very little and a longer interval might be reasonable. Im thinking the Mercury recommendation is assuming the motor is being used at WOT on a power boat when in fact my engine runs 95 percent of time between 2000-2500 rpm.


I have a spare in my toolbox of course, and all the right tools on board to replace.

If I do decide to honor the replacement interval it will be a Thanksgiving project so I dont miss any boating off season.
User avatar
crackles
Deckhand
Posts: 40
Joined: Thu Jul 21, 2005 10:56 pm
Location: Sydney, Australia
Contact:

Post by crackles »

After launching two weeks ago, I had only motored 100 yards when alarms starting sounding. My engine was overheating severly and no indicator stream. Never found out what caused it. Managed to get back to shore after five short runs and one hour's effort.

Back on the trailer and spent that weekend on the boat, on the trailer - in the carpark. But we had a lot of fun anyway.

First thing Monday, took it to the marine mechanic. He had the leg off in ten minutes. The impellar out in another two minutes. Cooked! Absolutely cactus and the housing was also beyond salvage. I then had to drive 80 kilometres (50 plus miles) to two different suppliers to find the parts and return. Back together in ten minutes and back on the water. A total of less than 30 minutes labour plus parts. Cost $180 Australian. Now that I know how to do it, I'll carry a spare impellar and a little grease.

I think I got out of it very cheap. I could have very easily siezed the motor. BTW, it's a Yamaha.

On all my last boats, ( all runabouts ) I had an annual service done which included impellar servicing. Never had a problem. This boat is new to me and I think I will continue with the annual service. Cheaper than breaking down while on the water and being towed back.

I'm new to this sailing thing and I much prefer to have a motor that works to get me home, just in case.
Billy
First Officer
Posts: 439
Joined: Tue Jan 06, 2004 3:50 pm
Location: Dunn NC 2001-26X140 "XX"(DoubleCross)

Post by Billy »

I now have about 350 hrs. on the original impeller on my Suzuki 140 (2002 model). Before going to the Bahamas this past June, I decided to change the impeller. After discovering the last mystery bolt to drop the lower leg, I found the impeller looked just like the new one that I was about to install. I decided to keep the new one as a spare and reinstalled the original. I carry the tools to change out if necessary.

As Frank mentioned, the bolts probably need to be broken loose annually. Upon removing mine, I discovered 1 bolt was slightly shorter than all the rest--most likely the other part of the bolt is still in the hole. I put that one back into the same hole. (I didn't want to create any new problems.) I plan on breaking down mine every year now--especially since I do a lot in salt water.
User avatar
argonaut
Captain
Posts: 531
Joined: Sun Oct 24, 2004 8:23 pm
Location: '97 26X, Yammy 40 4s, Central Fla.

Post by argonaut »

.
I toasted my first impeller the first month I had my used boat. OK, maybe my ears weren't on right, I didn't cover up the anti-cav vent once. (under the anti cav plate...)
The second impeller was installed by a local marine mechanic for big bucks.
It toasted next time I put her in the water. Peed for like ten seconds.
I have tools and have taken motors apart... not outboards. I called every mechanic in my phone book instead.
All the local guys would gladly work on anything but Hondas. Joy.
Bought manuals, ordered parts because noone in a 200 mile radius carries any.
Did it myself. Took a weekend morning, next time should take 10 minutes.
5 bolts, drop the lower unit, 4 bolts on pump housing, remove, replace and reassemble, following MANUAL's diagrams. Aligning the shaft teeth takes an extra second or two but isn't as scary as it sounds.
Pees great now.

Oh, and my highly paid mechanic stuck the dang impeller I paid good money for in backwards, and used an aftermarket replacement instead of a Honda part. My boat was in the shop three weeks to get that ten minute job done too.

Salt water, sandy or abraisive environment, replace annually. You need to be in there anyway.
Fresh water, every 2-3 years. If you wait too long the SS fasteners can gall into the aluminum housing and that's not pretty.
And always keep spares on hand because Honda parts are like hen's teeth.
User avatar
Robert
First Officer
Posts: 362
Joined: Wed Jan 28, 2004 6:12 pm
Location: NC

It depends how much you need dependability

Post by Robert »

I used the same impeller almost three seasons, then had an overheat alarm and had to limp back to the dock by waiting for it to cool then run it slow below the Suzuki 3000 RPM temperature shutdown. It took a while to get back even on a lake with little wind, my kids and the Admiral were very unhappy. The Impeller had lost a vane. That little piece of rubber had to be located inside the motor and removed, that took some time. Since then I go with the annual checkup including the impeller change.
..
If I were crossing a major ocean current I would want my outboard to be very very reliable. Remember the story of the guy that lost his mast and radio half way to Catalina and was found many weeks later alive off the coast of South America living off seagulls he baited with rotting turtle parts? That sort of thing could happen in the Gulf Stream off the east coast also. I would add a second 2way radio with its own battery to my requirements list on such a trip.
..
Good thing the Mac26 comes with two engines, one on the transom and one on the mast. The two engines idea is one of the reasons I like the Hysucat RIB with a pair of 50hp OBs each with independent fuel and electrical systems.
User avatar
Mark Chamberlain
Chief Steward
Posts: 53
Joined: Sat Jan 03, 2004 6:57 am
Location: North Pole Alaska
Contact:

impeller replacement on Honda bf 50

Post by Mark Chamberlain »

The number 1 reason a impeller fails is running the motor out of water, even for 30 seconds. It creates a great deal of heat and the rubber will fail making the blades weak and bend when the water is forced. The blades can look fine yet bend 50% when under stress.

The cup the blade truns in will also wear out at some point. You can replace the cup made of thin ss at the same time. I have about 300 hours on my motor and will replace again next spring. This will be the second time.

If you are in sand and in shallow water often and kick up the sand, you will wear the inpeller out at a much faster rate.


Breaking the bolts loose is something that should be done at least ever two seasons.

Dont for get the bolt under the rudder guide. I must replace that this year also due to the salt water I use the boat in.

I take no changes with the motor, many times I am in areas where there is no help for 25 miles. The Other number one item to fail in a outboard is the fuel, connections checked, o ring, clean fuel, and run seafoam in the gas the last tanks of the season.

Lower unit gear oil change each year, check for water or gray oil, water can get in it and freeze in winter time. Lower units can get hot an bust if the oil fials due to water.

Pack wheel bearings every two years, even with buddy bearings,
The rear seal will leak, this is caused by the buddy bearings when pumping them full of grease. If in salt water like me, this is a must so your trip is not runied on the way there. I travel 700 miles each trip
to the coast 5 times a year.

Take no chances and you will always have a trip of enjoyment instead of cussing frustration.

Mark


Mark
:macx:
User avatar
Catigale
Site Admin
Posts: 10421
Joined: Fri Jun 11, 2004 5:59 pm
Sailboat: MacGregor 26X
Location: Admiral .............Catigale 2002X.......Lots of Harpoon Hobie 16 Skiffs....Island 17
Contact:

Post by Catigale »

and run seafoam in the gas the last tanks of the season
I scooped up some seafoam from the Bay, put it in my tank, and the engine stopped.

What did I do wrong??

:wink:
User avatar
RobertKing
Deckhand
Posts: 42
Joined: Mon Aug 29, 2005 10:46 pm
Location: Daytona Beach, Florida

SeaFoam

Post by RobertKing »

Ive been using Seafoam for years, its a great product. I cant find any here in Daytona so whenever my friends from Minnesota come to visit I have them bring me some. Just used it on my lawnmower, cleaned it out and now it runs like new.
User avatar
crackles
Deckhand
Posts: 40
Joined: Thu Jul 21, 2005 10:56 pm
Location: Sydney, Australia
Contact:

Post by crackles »

Looks like anothe U.S. based product. What is "Seafoam"
User avatar
RobertKing
Deckhand
Posts: 42
Joined: Mon Aug 29, 2005 10:46 pm
Location: Daytona Beach, Florida

seafoam

Post by RobertKing »

Seafoam is a cleaner fuel additive. For carb engines you would actually run the engine and pour it in the carb, finally flooding out the engine, let it sit for a few hours and start it up. You could feel the difference in performance. The smoke was also good for pest control. Now I just put a little in the tank once a month to help keep the injectors clean.
Post Reply