BajaNomad - Impeller replacement?

Impeller replacement?

Santiago - 7-4-2012 at 12:20 PM

I have a 115hp 4-stroke EFI Merc ourboard that stays in Baja. Last trip down we did the annual maintenance: engine oil/filter, lower end gear oil, lube points, fuel filter both in-line and the smaller one in the motor. I did not replace the impeller as I do that every three years or 300 hours which for me is about the same and next year will be three for the current impeller.
On our last day we hooked up the hose to the engine to flush it, turned it on to idle for 10 minutes and in two or three minutes the over-heat alarm came on. I let it cool, turned it on and the same thing - this time I noticed no water coming out the pee-hole.
Once back NOB I go to the dealer and he says my impeller is bad and in fact, it should be changed every year and I quote, "because of where the boat is stored".
Fine, so I buy an impeller kit but later on my buddy wonders why everything worked fine for 4 days, including that very morning, but as soon as we pull it out, no water? We're thinking that maybe under power the impeller is still able to pump some water but at idle no? Is this possible? Do you guys change your impellers each year?
They also told me to plug the hole with tape when I'm away to keep bugs from setting up home in the pee-hole. That's probably a good idea.
I always thought only some of the water came out the pee-hole so the driver could see that water was being pumped, the rest flowed out the lower end. Am I wrong about this?
By the way, I was able to get the shop manual for this engine on eBay in disc format for $8. Not the owner's, the shop.

woody with a view - 7-4-2012 at 12:24 PM

every other year is what i've been told. the parts are fairly cheap and would be easily do-able on a warm BOLA morning after you unpack. might as well do the water pump too!

but then again, i'm just getting started on this private boat thing....

Santiago - 7-4-2012 at 12:44 PM

Ok, I should of spent more time reading the shop manual before posting. I found a water diagram and a little of the water is shunted to the Tell-Tale (not the pee-hole). It looks like a pretty small tube so could easily get plugged.
By the way, I got the impeller kit with the gaskets, o-rings, etc but not the housing.

Santiago

captkw - 7-4-2012 at 12:53 PM

Hola,,,If Your "manual" is a seloc,chilton or a haynes..UMMM !! thats good fire starter !!! LOL :lol:

get the real mccoy...if its a honda, the BOOK will be printed by honda...if its a yamaha,its printed by yamaha..Very big difference !! and I strongly reccomend new impeller yearly..cheap !!I'm trying to diagnose your post..the diapham would be the poppet valve ???..K & T...out for the afternoon !!!

[Edited on 7-4-2012 by captkw]

BornFisher - 7-4-2012 at 01:25 PM

Here is a discussion from BD------

http://www.bdoutdoors.com/forums/boating-discussion/67107-ye...

Santiago - 7-4-2012 at 02:27 PM

I found this great video so between the few I've done in the past and the Merc shop manual it's a simple enough procedure. I will need to run this thru Google translater though....

[Edited on 7-4-2012 by Santiago]

fandango - 7-4-2012 at 07:30 PM

santiago:
i just had my impeller replaced by a shop. because the impeller was set from either heat or non use the water wasn't pumped properly and it messed up the housing which had to be replaced. shop guy recommended changing the impeller each year or 100 hours. the housing comes with an impeller kit.

if there is any impeller residue on the housing it will mess up the new impeller.

Impeller change

captkw - 7-4-2012 at 08:30 PM

Hola, as a 52 yr old mec/tch I can tell you that there is lot a varibles on impeller design,wear and tear factor and The Biggest, lack of use !! No way on every 100 hrs..thats a joke!! the main reson a impeller needs to be changed yearly is that when not in use they get a "SET" and will be fine on a garden hose but asking it to work out on the bay is a whole different storey..the blades have to snap in a offset circle and when they lose there flexible service they just dont pump correctly..and at higher speeds the vanes must also flex to allow the water to pass the vanes for high volmes of water to pass as the boat moves through the water..sorta by passing the impeller if you will ...and if you want to change it yourself,,first have a real boat mec walk you through it as there is a LOT of tricks and things to look for!! I have watched a lot of vids on you tube and and read Iboats and its ALL BS..there is this one yahoo who even puts grease (A no/no) in the waterpump housing..so dont put off getting your impeller serviced!! no. 1 reason for blown pwr heads/overheating!! K&T :cool:

WRONG !!

captkw - 7-4-2012 at 08:40 PM

Quote:

Originally posted by BornFisher
Here is a discussion from BD------

http://www.bdoutdoors.com/forums/boating-discussion/67107-ye...

HOLA,,

THATS FUNNY !! HEY,,I got a good drill..need some teeth work done ?? my point? do you want to f/up up a $ 9k motor after watching a yahoo who thinks he has a clue.. :lol:

K & T

Oggie - 7-4-2012 at 09:06 PM

In Bahia de los Angeles see Pancho Verdugo for this kind of work.

Hook - 7-4-2012 at 09:17 PM

I use a light coating of silicone grease on my impeller housing and change the impeller about every three hundred hours. No failures yet. What am I doing "wrong" by using grease? Especially if it's an outboard, with no sea strainer.

I avoid the Sierra impellers and the Sherwood impellers. I use Johnson Pump impellers. They are neoprene.

Volvo diesel, not an outboard.

We have temp gauges, so the #1 cause of blown power heads is inattentive skippers. :lol:

HOLA, HOOK

captkw - 7-4-2012 at 09:26 PM

JOHNSON and volvo(which is johnson) impellers come with Glycerine ( had to run to car& get tube to spell right) and when in the bush might use dish soap !! but oil.grease.screws with the rubber from the first minute of contact !!I myself as a young lad made the same false asumtions..live and hopefully learn !! you are taking the time to at least learn boats...most folks assume !!K&T :cool:

VOLVO DIESEL

captkw - 7-4-2012 at 09:39 PM

LET ME GUESS.......KAD 42 OR KAD 46 SERIES WITH SMALL TURBO AND SWICTHING COMPRESSER ??? K & T :cool:

PS..SILICONE IS NOT PETRO/GREASE..AND IF YOUR RAW WATER PUMP IS HIGH UP PORT SIDE I HAVE A LITTLE STORY TO SHARE W/YA !! K&T OUT

[Edited on 7-5-2012 by captkw]

Hook - 7-5-2012 at 07:41 AM

No. Older 41A diesel. Turbo and aftercooler is all. 2300 trouble free hours, so far.

I have the sea strainer out right now as it began leaking SOMEWHERE. Either one of the tubes leading into the strainer or possibly from the impeller housing (but not the faceplate).

Having trouble freeing the impeller housing from the water line below it. First time I've done anything but replace an impeller on this system.

Hoping it's not the seal at the back side of the impeller assembly as it's driven by (and lubricated by) the same mechanism as the injection pump. But I see no signs of salt water intrusion into the crankcase oil.

Pescador - 7-5-2012 at 08:16 AM

Okay, I have had three different boats in Mexico and I do a change every two years. I do a lot more hours than you do but still the every other year seems to work fine. You have a Merc but it was built by Yamaha so the motor is pretty much the same.
You probably had some break down in the impeller which still allows water to flow, so it was ok when you were out fishing, but when you were in rinsing, the flow is restricted more. On the new Yamaha's with the hose connection, the factory does not want you idling the motor when connected only to the hose, you really need to use Mickey Mouse Ears for that.

HOOK

captkw - 7-5-2012 at 08:23 AM

HOLA,Craftman sells a handy tool called a cotter pin removel tool that makes hose removel alot easyer !! its more or less a 90 angle pin that you start under the hose end and run it around to break the hose free !! best little tool in my box!! ..I/O'S and inboards have a lot of hoses...volvo's ROCK SOLID !!! K & T :cool:

PS just saw pescadors post and yes the pwr head is a yamy and I always recomend flushing with the muff's..K & T

[Edited on 7-5-2012 by captkw]

Hook - 7-5-2012 at 08:31 AM

Yeah, I misspoke earlier. I use the glycerine rather than the silicone grease.

Cappy, it sounds like a small Allen wrench might do the same thing as the cotter pin removal tool, no?

HOOK

captkw - 7-5-2012 at 08:44 AM

Hola,, NOT the same..but close..if your haveing the hose stuck to the pump the tool that I use can be pushed in between the hose and the pump "barb" and you run it around as much rooms allow to break the "seal>>>>> I guess in a pinch you could take a 90 allen wrench a grind the 90 at the tip to work.. the craftsman tool is cheap and I myself could not do a inboard without it..I know because I have had to help folks out at the ramp on few times I did not have my tool bag with me... funny thing most folks assume that you can loosen the hose clamp and it will just come apart..NOT !! K & T :cool:

Hook - 7-5-2012 at 10:51 AM

Got it off. No signs of leakage past the seal at the rear of the impeller housing. But I'm headed to the "expert" in town.

Now, what about that Volvo story? My impeller housing is high up on the port side. Dont tell me someone went and added engine oil here?????

hook

captkw - 7-5-2012 at 12:45 PM

Hola,as always Im confused???? is the pump or the strainer thats leaking?? or all of the above..sometimes I have gone to real auto parts store and used the blue light stuff to find a leak and the last time it was on a volva KAD 42 sweet diesel engine..did ya catch that?? LOL :lol:

K&T

Hook - 7-5-2012 at 12:54 PM

The "expert" says, YES, the seal is leaking. There is a spring that is supposed to be inside of the seal and it is gonzo, leaving quite a bit of telltale rust on that end of the impeller. It just rusted away...............maybe electrolysis from spending a month here and there in a electrically "hot" marina? That seal is about 5 years old.

seal

captkw - 7-5-2012 at 01:15 PM

Hola< get a new pump..do not try and rebiuld it.... not cheaper in the longrun..and I think that motor has fresh water cooling..you might run some saltaway in her and let it sit with the S.A. in the cooling system!! K&T

vacaenbaja - 7-7-2012 at 10:10 PM

It was interesting to watch the videos on pump servicing. In mariine
mechanics school our instructor Russ Sandore had quite a few years
of experience and passed down a lots of the hard learned and earned
tricks of the trade. Even the factory manuals are the Abc's at best.
You will run into problems like seized fasteners that may requier the
carefull use of a "hot wrench" and special tools galore that make the
job possible or easier. Before any waterpump service we were
taught to perform a vaccum and pressure test to check the condition
of the various seals in the drive. Also to note the condition of the
lubricant that is drained from the gearcase that could also tell you of water intrusion through the failure of these seals. We would be careful
to tape the splines of the shaft if we were to pass a seal by it to avoid cutting the new seal. A pair of Stevens vac/ pressure pumps
are indespensible. As Russ would say" Guys don't cheapsuit it, go
with the OEM part and if in doubt replace it, its cheap insurance."
I would also be very wary about using a screwdriver to split the aluminum cases on any drive aluminum always loses when put up against steel.

[Edited on 7-10-2012 by vacaenbaja]

4baja - 7-22-2012 at 05:45 PM

Quote:

Originally posted by Oggie
In Bahia de los Angeles see Pancho Verdugo for this kind of work.

yea but panch is so busy fishing in the summer that it will take to months to get it done. but yes he is very good.

vacaenbaja

captkw - 7-23-2012 at 07:52 AM

HOLA, a mityvac is easy to find and works great.. no need to pressure test a gear case unless the oil is milky or low or missing.....LOL and use the right lwr end oil and fill procedure !!! they are all not the same...I have yet to see a You tube video about marine engine repair,service that was/is correct!!! sorry but this type of motor work info is not avable to the public and is coveted for many good reasons!! not a week goes by that I hear "I'm a mec at the ford dealership for 25 years,,I can fix it"...I cant count how many folks screw up a good motor/lwr end... trying to save a few bucks by doing it themself...save yourtself the greif and get reff's from other/older boaters and go to the guy that they recommend..and plan ahead.. If the guy is good.he will be busy and booked out!! if your planning a trip say 4th of july..you better call him june 4th and pray he dosnt fall or get sick...LOL.....K & T.. :cool:

woody with a view - 7-23-2012 at 08:00 AM

anyone know a good aluminum welder in SD? i got two 3inch cracks from the bunkers when the tie down strap came loose...... :fire: