Suzuki DF150 Overheating

[hrl]

I am at the end of my rope with this outboard and hopefully someone can help me. I have a 2010 Suzuki DF150 that overheats at low rpm. I have replaced the thermostat, impeller and water pressure valve, flushed the engine through the thermostat housing (nothing came out), removed all the anodes and checked for corrosion or build up and nothing has remedied the problem. It has been run in freshwater only and has 365 hours on it. This is literally the first problem I have had with this motor and it is driving me crazy trying to get to the root of the problem. Hopefully someone can point me in the right direction as I live 2.5 hours from the closest dealer and don't have the time to take it there.

 

[99yam40]

when did it start overheating and under what conditions?
Did you do anything right before this started happening?

when did you replace the pump stats and PRV?

Did you replace just the impeller or did you replace the other parts of water pump also?

 

[hrl]

Started overheating while idling out or launch area. I shut the motor off and waited a few minutes. My engine is wired to my Lowrance graph so I switched to the gauge screen to monitor engine temp. Started engine and continued out from launch. I increased rpm to approx 2000 and temperature began to come down. It would maintain roughly 150 degrees as long as I didn't idle for any length of time, in which case temperatures would climb until the over temp alarm would sound at approx 210 degrees.

Initially I changed the impeller as the stream out of the pisser didn't seem too strong. That made no difference at all. I then changed the water pressure valve and thermostat. While the thermostat was out i flushed the engine through the thermostat housing with the lower unit removed. Nothing appeared to be flushed out. I removed and inspected the water pump assembly and nothing appeared to be out of sorts.

Re-assembled the outboard and ran it up at the launch this morning and same thing. High temp at low rpm, increasing rpm brings temp down.

 

[99yam40]

Well sounds like the pump is not pumping enough water or the water it is pumping is not getting up to the block.

replacing water pump housing, cup and wear plate may help
or making sure the seals where the tube sits in housing is seated properly