Tell Tail Weak

[striker44]

I have a pair of 225 four stroke yamaha engines. The starboard engines the flow out of the tell tail is very weak. I changed the water pump and cleared the lines with compressed air. Still the flow of water through the tell tail is very weak. There is no sign of overheating at all. Any advice where to look next?
=

[rodbolt17]

next would be the thermostats then the pressure control valve then the exhaust stack.

[99yam40]

I have a pair of 225 four stroke yamaha engines. The starboard engines the flow out of the tell tail is very weak. I changed the water pump and cleared the lines with compressed air. Still the flow of water through the tell tail is very weak. There is no sign of overheating at all. Any advice where to look next?
=

Did you replace just the impeller or whole kit, and housing?
Is it weak at all RPMs?

If so, Make sure the tell tail passage does not have something restricting it.
A piece of heavy mono fishing (weed eater) line shoved in and moved around sometimes will help even if the compressed air did not.
If you have the lower unit off again you can hook a water hose to the tube to power head to see if there is good flow through tell tail to rule out blockage in it.

[seahorse5]

The starboard engines the flow out of the tell tail is very weak.

Be aware that the water that exits the tell-tale is used to cool the regulator on your motors. If it is restricted or plugged up, the regulator can overheat and cause problems. Get the situation resolved as soon as you can.

Listen to Rodbolt17

[TimC2520]

Rodbolt,

I know it is difficult to speculate, but if it is something with the exhaust stack, what does your experience say? Big job? big deal? or a relatively minor repair? Any experience with a weak tell tail being the result of an exhaust stack issue? Is it bad gaskets? seals? corrosion? I am having the same situation as the OP. Different engine though, S225TXRX

[striker44]

weak tell tail

Thank you for the quick reply. The problem was the thermostats. Both were partially blocked.Thanks again.

[rodbolt17]

300-500 hrs is prime for failing stacks.
some engines go over 5000 hours little used engines tend to fail faster.

beats me as to why but is has NOTHING to do with flushing as it corrodes from the ex side into the cooling water side.

flush till the cows come home, the blue jays roost or the bear poops in the out house.
fresh water wont help.

[boscoe99]

Information on line says that Yamaha used a treated corrosion resistant stack on 225/250 engines after 2004/2005.
Any truth to this?

I'm asking my local dealer a few questions about stack corrosion on my particular model and year.

A number of mid-section parts have been upgraded over time. Not all at once. Some parts were changed at various dates. Some parts have been changed several times. It remains to be seen if the latest parts can withstand corrosion damage.

Yamaha offers a "kit" of parts for a mid-section repair. The list of parts included in the kit is provided below. You can go to the Yam parts catalog and look up your specific motor to see the part numbers used in it during production. Then compare your original part numbers with the latest upgraded part numbers.

[Hedland1]

225 weak tell tale

I just posted an issue about weak tell tale. (137hrs) I spoke to the mechanic and he said that new motors (2012 motor I think) were all like this and the owner said it was always like this and he's had no issues and no faults etc. the water was quite hot at idle and cooled slightly when we got under way. New impeller was fitted at 80 hrs but it seems a bit funny. It didn't pick up any stronger when we were motoring