Why change impeller so often? 43 years on our so far on original impleller.

[brmurph]

We have a 1968 Merc 650 that my dad bought new and has never changed the impeller yet we have never had an issue with overheating and it seems to pump water just fine. Thats 43 years on the same impeller. I agree it probably should be replaced by now but why does everyone seem to recommend replacing it every few years or even every year ? Are the materials they use today not as good as they were in 1968 or have we just been extremely lucky? BTW we also have a 1964 9.5 Johnson (also bought new by my dad) and same thing, the original impeller still seems to work fine (well actually I did have someone put a new impeller and seals in last year on the Johnson just as a precaution and now the lower unit leaks pretty bad :-( .. I'll have to go in and fix it myself as the guy really doesn't want to work on it anymore. Hence I am afraid to have any work done on the 650 (guess I will have to do it myself).. I will admit both motors did/do show signs of a little water penitration into the lower unit (little milky) by the end of the summer but water pumps just fine.

Thoughts ?

 

[Scott Danforth]

Re: Why change impeller so often? 43 years on our so far on original impleller.

your so extremely lucky you should buy a lottery ticket today. Rubber wont last 43 years. I bet the impeller is dried up and hard as a rock.

any water in the oil indicates a leak. I would address that too while changing the impeller.

 

[ThumbPkr]

Re: Why change impeller so often? 43 years on our so far on original impleller.

I have two 650s,a '69 and a '70 and when pulling the lower unit on both the shft shaft pulled out of the lower unit which can be big problems because it drops the C clip into the lower unit which has to be removed before the lower unit can be used.
If your engine was only used in fresh water it can improve your chances considerably when removing the lower unit to do so without damage.
The problem is corrosion and the shift shaft coupler gets corroded and locks the shift shaft so that it will not separate when the lower unit drops down so it pulls the shift shaft out of the lower unit and when it comes up past the shift shaft seal it knocks the C clip off and the damage is done.If you can snag the C clip with a long magnet you can save the day but I could not on my engines.
I took my original lower unit to a dealer and they destroyed the housing trying to get it apart so I took the other one apart myself.I destroyed the carrier cover nut but was able to get the carrier out without doing any damage by fabricating a puller to do the job plus using some heat to help me along.I think that the impeller on the '69 was original too.I bought the engine in '78 and never changed it.Ron G

 

[bgc]

Re: Why change impeller so often? 43 years on our so far on original impleller.

Two thoughts....
Changing the impeller every other year persents and oppertunity to grease the splines slowing down some of the corrosion issues....

I would'nt risk a classic engine over a 16 dollar part that easy to install.....

 

[lncoop]

Re: Why change impeller so often? 43 years on our so far on original impleller.

The thing about impellers is this. Unless you are watching the telltale while driving the boat you won't know the impeller has failed until it's too late. My buddy just picked up a sweet little '78 Ouachita bowrider for a grand that was basically ready to go. It had been sitting in inside storage for ten years or so. We were going to the lake that weekend and he really wanted to take it. We fired it up in my driveway and it peed like a racehorse, so he pronounced it good and made plans to take it to the lake. I told him I didn't think that was a good idea unless he had time to replace the impeller. He said "but it's peeing good", and I said "it is now. What happens when you're pulling someone on a tube at WOT and the dry rot finishes it off? You'll discover the impeller is bad when you discover the motor is locked up." May have been fine, but why risk it? Impellers are cheap. Motors aren't.

 

[ohioriverat]

Re: Why change impeller so often? 43 years on our so far on original impleller.

Two thoughts....
Changing the impeller every other year persents and oppertunity to grease the splines slowing down some of the corrosion issues....

I would'nt risk a classic engine over a 16 dollar part that easy to install.....

right on, if nothing else you get to keep the bolts from seizing and the driveshaft lubed, i have had several old motors that the lower unit bolts would not come out because of no maintenance. anti seize is your best friend!!

 

[apaseman]

Re: Why change impeller so often? 43 years on our so far on original impleller.

I think the slogan "An ounce of prevention is worth a pound of cure" sums it up rather well

 

[bgc]

Re: Why change impeller so often? 43 years on our so far on original impleller.

I think the slogan "An ounce of prevention is worth a pound of cure" sums it up rather well

Amen

 

[brmurph]

Re: Why change impeller so often? 43 years on our so far on original impleller.

Good point on the corrosion. Now I am worried about breaking it apart since it works fine now . Thanks for the info and if you have anymore tips on doing this for the first time after 43 let me know (this has always been in freshwater BTW). I assume once you start into taking the lower unit off your pretty much commited or can you just rebolt things back together if its all coroded and expect it to work (minus any broken bolts of course).

Guess I am nervous since our Johnson 9.5 came back from the shop in worse shape then it went in after impeller and seal replacement. Still think impeller replacement every couple of years seems like over kill though, of course I suppose it depends how often it gets used

Thanks!

 

[j_martin]

Re: Why change impeller so often? 43 years on our so far on original impleller.

43 years?

I'm callin' BS

 

[ThumbPkr]

Re: Why change impeller so often? 43 years on our so far on original impleller.

Knowing what I know now I would drop the lower unit every couple of years at least just to have a look because it is easy to do.I would check the impeller even if I didn't change it because it would be easy to do since I had it opened up.Of course this would be my opportunity to get neverseize on the couplings and shafts so that when it needed to come apart there would be no problems.
I find that fresh water motors seem to get along pretty good dealing with corrosion but the salt water really seems to do a job on them.If mine had been serviced properly I would have gotten my boat in the water this year but it may be another year before I get to run it.Ron G

 

[brmurph]

Re: Why change impeller so often? 43 years on our so far on original impleller.

43 years?

I'm callin' BS

Yeah and even in your neck of the woods, well in Minnestoa anyway (Lake Vermilion). I don't bet my life on anything but hey when your the original owner and you have never had to take it in for service except for a rectifier 20+ years ago because we hooked up the battery backwords (not paying attention) its pretty easy to say that is the case. I know they did not replace it then cause we were out of town and in a hurry to get to the lake that day (Kabetogama) Now I am only 1 year older then the motor so I suppose in the first 10 years of ownership there might have been a service that neither my dad or I remember but I doubt it (dad keeps pretty good records). Llike I said we have two motors (1964 Johnson and this 1968 Merc) that made it this far on original impellers.

After our bad experiance on the Johnson during WP and seal replacement I am not sure I can convince my dad to replace it now ... He is afraid to have anyone open it up after all these years and the fact that its hard to find a shop to work on these older motors.

Have fun.

 

[turtles11756]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

sooner or later the lower unit will have to be dropped. take your time don't force anything ! if you get lucky when ALL is disconnected the lower unit will fall right off. grease everything when you are ready to put it back together. you will get help here with any problems and you will know your running the motor with a new water pump impeller

 

[River Boy]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

Wow 43 years. I've never burnt up a motor on the water but through the years I have had two get hot on me because I had my HUMA and didn't do what I should have done, and that is, check out the impeller at least every couple of years.
I've got a theory that OMC impellers with their longer vanes last longer than Merc impellers with their shorter vanes. Maybe the Merc impeller has to 'work harder'. I run both OMC and Mercs, and don't prefer one brand over the other. Both are good American made products. It's a Ford Chevy thing with me I guess. My current small, river motor is a 4.5 Merc and it likes to eat an impeller every year. But then I keep it in the gravel and mud. My larger river motor, for when the river is up, is an old 9.5 just like you have. For some reason the impeller is always good when I look at it. I change it anyway and throw the old one in a box for a spare.

Well, if you feel lucky, see if you can get 45 or even 50 years out of that impeller, but if it was me I'd be RUNNING to the parts house and getting a new impeller for less than 15 bucks and spending the 30 minutes time it takes to install it. PS, when I travel I make sure my spare tire is aired up too. River Boy

 

[jigmister]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

43 years??? I think that is BS if I ever heard it. If you have an oz of mechanicl knowlage you know it is BS.

 

[secretariatslew]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

I can second that 43 year tale with a 47 year impeller off my 64' 3hp Johnson that lost a little pliability but was still functional and 100% intact. Who knows how many years it sat unusued before I cracked the pump case?

 

[brmurph]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

43 years??? I think that is BS if I ever heard it. If you have an once of mechanicl knowlage you know it is BS.

Could I be wrong? (I suppose anything is possible) but BS? Seems a little harsh. I am somewhat new to the forum so maybe this is just your guys way of welcoming me. LOL Thanks for the guys that support my information as I am sure I can't be the only one that the lower unit has never been dropped on.

Enjoy.

 

[windy5849]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

I have a 1990 Merc 25hp which I purchased new.After joining the forum and reading numerous posts on impellers,I changed mine this year.After 21 years of light use,the impeller was still pliable,but did have a slight set to it.The $25 dollar pump kit seems like cheap insurance and I feel very lucky to have made it this far with no damage.

 

[bgc]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

brmurph,
Sorry there are some salty dogs on here and some really great people. It?s just cheap insurance to change the impeller and perform all routine maintenance. The last thing you want is a problem when you?re out on the water?? and there is nothing like the grimace your spouse gives you when you walk in smelling of 2 cycle, bleeding and gloating over your accomplishment of ?fixing it again? (for the fith time)

 

[brmurph]

Re: Why change impeller so often? 43 years on our so far on original impeller.

Re: Why change impeller so often? 43 years on our so far on original impeller.

Totally agree that 43 years is waiting to long, no argument there and will probably need some help from this forum when I do finally replace it so hopefully I am not offending anyone. I just picked up this motor (looks just like our 650 just smaller, same year) to stick on the transom in case we do break down http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110731838657 ,been wanting this as a backup for 30 yrs, hope it ends up being as nice as it looks in the pics. And yes according to the seller it has a new impeller .. Still no excuse for not getting that old impeller replaced on th4e 650 though..

Thanks..