Small Tohatsu/Nissan OB Impeller life

[HT32BSX115]

Howdy all,

I know there's OBs out there that have probably NEVER had the raw water pump impeller replaced (and they still pump water!!)

And I would not let the raw water impeller go more than about 2 or 3 years in my Bravo.

I bought my little 9.8 4-stroke Tohat in 2003 and have not used it sometimes for more than 2 years at a time.

Every time I put it in the water not only does it start and run perfect (starts on the second pull even after sitting 2 years) but the raw water pump immediately starts pumping water. (AND I never use snake oil in the gas....I just run it out of gas before storage.....but that's for another thread!!)

How long should one not "fix it if it ain't broke" or am I running on borrowed time? I would NEVER run a Bravo impeller this long


Cheers,


Rick

 

[Sea Rider]

I run my Tohatsu impellers 1,000 metered worked hours, flip impeller along a nice liner polish to a smooth finger rub cond each 250 hours. Can do this due to using all my OB's year round, so impeller doesn't sit compressed at one point which hardens, cracks blades. Tohatsu impellers are made from elastomers way flexible than plain rubber as seen on most other OB brand impellers which needs to be changed on a yearly basis.

Tohatsu recommends changing every 2 years or 300 metered worked hours if wanting to be on the safe side, you decide.

Happy Boating

 

[HT32BSX115]

Tohatsu recommends changing every 2 years or 300 metered worked hours if wanting to be on the safe side, you decide.

Happy Boating

Yeah..... 14 years might be a tad excessive then......

 

[Sea Rider]

Yep, change it, could be already dried or hardened and break vanes with subsequent overheating at any time. Are not costly.

Happy Boating

 

[HT32BSX115]

Yep, change it, could be already dried or hardened and break vanes with subsequent overheating at any time. Are not costly.

Happy Boating

I should know better!!!

 

[pvanv]

The issue with light use is that the impeller will dry out over time, even if not used. In cold fresh water, we usually go 3 years. In silty water, one year or less. Always do a complete water pump kit, instead of just the impeller. Same labor, slightly higher cost, pumps a lot better and longer. If the vanes snap off and get pushed into the cooling system, you will have a bigger job (getting them out) than you would like.

 

[HT32BSX115]

Ok. Over here at Roosevelt Lake. Having a great time by the way!

I feel I can usually fix most anything and am feeling pretty stupid today!!

We all cruised up the lake 20 or so miles, put down the anchor and got the Wonderful FourWinns 211 LIberator all parked, anchor set and got the Zodiac out and inflated!

Everything was going just peeeeechy!!

Put the Tohat on the back, hooked everything up and fired it up.......guess what?

NO PEE!! ........the 9.8 Tohatsu didn't PEE right after startup.............. Like it did with the 14 year old impeller ....... every year for 14 years!!

AND by the way, when I pulled the old impeller, it was actually OK. I could have just left it in there and it would have been just fine!!!!

All l I had at the lake was a 6in crescent wrench and a nail from the outhouse up above the beach at the boat-in campground!!

SO, I used the nail and a rock to tap the pin out of the shift rod........... and the 6in Crescent to remove the 4 10mm bolts in the lower unit and the raw water pump housing.

Anybody else know that you can install a 9.8 and ( presumably) other small Tohatsu raw water impeller housings 180 degrees off (if you're not paying close attention to detail)???

I thought I had left the little impeller pin out. GAWD I FEEL STUPID!!

Good thing I only ran it long enough to determine that it wasn't pumping.


If anyone else is replacing their small outboard raw water pump, DO NOT LET ANYONE DISTRACT YOU WHEN YOU PUT IT BACK TOGETHER!! (my excuse!!)

All of us are fallible!

Cheers,

Rick


Oh, and by the way......My "Stock" in Tohatsu went down JUST a little.......WHAT Dum-BASS engineer designs a raw water pump housing that can be installed backwards anyway???????

 

[pvanv]

Are you serious?
You CAN'T install it backwards.
How well did the water tube mate up to the pump housing? NOT. Of course, you checked that...
How did the wear plate and gaskets align with the pump housing? NOT. Of course you verified that before mating the LU back to the driveshaft housing...
Really?
Yes, we all get distracted, but that mistake is like putting disc brake pads on backwards.
Really?

 

[HT32BSX115]

How did the wear plate and gaskets align with the pump housing? NOT.
Yes, we all get distracted, but that mistake is like putting disc brake pads on backwards.
Really?

The wear plate/gaskets didn't align at all and I saw it immediately when I took it apart.

Can't say why I didn't see it going together. Clearly that would fall into "Famous Last Words" category

I wouldn't put it up there with brake pads going on backwards since it's been pretty much impossible on every brake job I have done.

But I still take full responsibility. I just hope to help prevent someone reading this from making the same mistake......It's what these forums are for right?

 

[preventec47]

I did put the nozzle of a diesel fuel pump into the hydraulic tank on a skid steer and fill it right up with diesel fuel. It had the writing below
the tank opening "Hydraulic fluid only" but the tank cap looked just like the tank cap for the diesel fuel tank. That is my worst screw up.

Thanks for the story as it has convinced me that the impeller job probably is not all that difficult if you can do it twice with a crescent wrench.

n of impellers. I have a newly acquired 25 year old M30A3 where the previous owner said he recently
replaced the impeller before I bought it. As I have found with lawnmowers... sometimes the parts used are new-old stock and
have been on the shelf for two decades and the compound in impellers may be already aged and hardened even though it
is brand new and never used.

 

[pvanv]

Never do just the impeller, unless a kit is not available. Always replace the cup and plate at the same time... same labor... pumps better, and lasts longer. Brand new kits are available for the 30A3.