Impeller pieces

[dehler25]

I have a F90 TLRB 2003 that was indicating the impeller was trashed, it was! Is there a way to backflush the cooling system to dislodge the remnant pieces? I have the lower unit still off so would using the flushing connector be as good as it gets?

[fairdeal]

leave the lower unit off while you do it
- if you succeed in 'backflushing' any impeller pieces,
you want them to freely exist the water tube.

the 'flush connector' flow is wimpy, and will be of little use.

work with the thermostat housing on top of the engine:
remove the thermostat, put the housing back on -
then adapt a hose to it,
so you can connect a garden hose, and/or your compressed air hose.

[boscoe99]

I doubt that there will be sufficient water pressure and flow from the garden hose flush fitting if this is what you are talking about.

Can you look up within the water pump tube and see what might be in there?

I would make some sort of device (tapered) that could fit within the thermostat housing to which would be attached a garden hose. Inject copious quantities of water there at maybe 30 psi or so and see if anything gets flushed back down and out from the water pump tube. Lower unit removed of course.

[dehler25]

I did flush with the lower unit off and looked up into the tube but did not see anything, I also have reassembled and do not get a flow out using muffs. T removed the lower unit twice to try my best to verify the tube is inserting into the impeller housing but it seems impossible to be absolutely sure, the tube is quite stiff so if off a little the unit would not go on smoothly and it does. I was going to pull the thermostat in case it was blocked and not 100% sure that I am looking at the unit. It seems to be on the right bottom side of the power head two bolts mounting and one in the center,I can'spot it in the exploded parts drawings

[DennisG01]

Thermostat will be at the top of the engine. It will definitely show on the parts diagram. That's a good place to look for pieces and, as mentioned, to flush from (keep the lower unit off).

[dehler25]

found it when I looked in the right place! Now I just need to get the stubborn unit out/I don't know what the other gizmo is it just sits in the cooling chamber like a sensor but no leads..

[fairdeal]

the thermostat housing (with the thermostat below it)
is right on the top of the engine -
you remove the plastic flywheel cover to access

letter "f" in this diagram:

[DennisG01]

found it when I looked in the right place! Now I just need to get the stubborn unit out/I don't know what the other gizmo is it just sits in the cooling chamber like a sensor but no leads..

Sounds like that other gizmo might be a sacrificial anode?

[dehler25]

Could be although there was only slight pitting functionally I doubt it could be anything else. Hooked up a double barb on the thermostat housing hose and a garden hose and back flushed a good stream. Did find that the thermostat is not opening. Thanks for the help saved me time searching!

[DennisG01]

Could be although there was only slight pitting functionally I doubt it could be anything else. Hooked up a double barb on the thermostat housing hose and a garden hose and back flushed a good stream. Did find that the thermostat is not opening. Thanks for the help saved me time searching!

The actual anode would be on the inside of the block. What you would see on the outside is a separate "cap" to keep it in place. The parts diagram would tell you for sure, though.

Edit: Look at this... anode or pressure control valve? https://www.simyamaha.com/category_s...rt-category=41

[fairdeal]