Pontoon Boat & Deck Boat Forum

Anyone have a Yamaha 90 and has replaced the Water Pump or the Impeller ? Is this something you can do yourself, and where on the motor are they ?
When I connect the water hose mount to the lower intake the water does not flow out, but when I connect to the flush out connection the water flows. The motor has been sitting for a while. I'm thinking it's the impeller rubber fins dried out and broken ?

Thanks,

Water pump impeller replacement is a regular maintenance type thing because they do indeed wear out/dry out. I have a 115 HP Yamaha and it is not hard to do, but it does require pulling the lower unit off. I proceeded after watching some YouTube videos and found it to be simple enough.

It's pretty simple. Are you sure your pee-hole isn't clogged? I use weedeater string to clear mine out....

First, let me tell you Yamaha's do not like flushing from the muffs that attach to the lower unit intake. My past 3 yamahas 225, 250 and current 150 all pee very little or not all from the indicator when running on muffs. this does not mean your impeller is worn, I just replaced mine in April first replacement since new in Aug 2015, still doesn't like to pee except when flushing through the flushing attachment on the engine (donkey dick). now there are articles all over the boating forums on the internet, whether you can run your engine on the flushing port, MFG says do not, not enough water flow, however my 225 2 stroke was never flushed on anything but that donkey dick and never had an issue. My 150 actually sounded the over temp horn once while on the muffs, now I simply flush using salt away and the donkey dick, engine off. If you are going to use flushing muffs, you must get the dual feed style like the picture, single side won't provide enough water. that all being said, if you have been setting up for a long time replacing the water pump is a good idea. the real test is how well does it pee in the water.

"Donkey dick"

What was your MOS ?

Only .gov folks get that leaky ass reference

bansil wrote: ↑

Mon Jul 09, 2018 5:03 pm

"Donkey dick"

What was your MOS ?

Only .gov folks get that leaky ass reference

My same reaction!

Navy Aviation Support Equipment (AS) AGE in the AF world. No Air Support Without Ground Support (NASWOGS)

Only a $28 part. Kits are seldom required if you are careful with gaskets. Pay attention to the direction the impeller veins were turned so the new one can be put back the same direction.

Bolts to remove the lower unit are easy to find--except for that one bolt under the bottom of the steering tab on the anticavitation plate. A hex wrench is required to remove the tab.

Go ahead and change the lower unit grease--draining it into a clean pan. f any sign of water intrusion, have the l/u pressure and vacuum tested.

19K here DAT