Df 140 over heating

[Mobbsy]

Hey all first time poster. I have a df 140 2002 model and it over heats once I get over the 4000 rpm. I have replaced impeller, water tube and all seals, water temp sensor, took thermostat out, done the drive shaft bushing while I was at it. Still over heats what would be the next thing to look at?? Has a fair bit of corrosion inside engine.

[artdf175]

there have been several discussions on overheating
one remedy was to run in a barrel with a heavy concentration of vinegar
the acidic wash evidently does a great job of cleaning up the corrosion

the 150/175 model has a water pressure regulator -there have been some reports of that being blocked open with debris preventing all the cooling water to go they the head
i am not sure if the 140 has a fresh water flush port for connecting a water hose
if so would get a new gasket and inspect behind this cover plate there should be a small hole that then feeds water to the power head
check for blockage
Art

[pniksnut]

this engine does have a presure relief valve

[pniksnut]

Knipselklep.JPG

located in the oilpan

[Moonlighter]

Many people, including members on this forum, have followed the vinegar flush process outlined in this thread on THT and had great success.

https://www.thehulltruth.com/boating...m-vinegar.html

And, make sure that you check and replace the internal anodes - it seems that many people neglect this, but its fundamental to minimising internal corrosion.

[briscoe]

Change the water tubing

I recently changed out all of the water tubing. These are the one that supply water to oil cooler, injector rails, VST etc. I found the exact correct size ID x OD at ORilley's auto parts. I was amazed at how small some of the tubing had shrunk over the 10 years of engine life.

[pniksnut]

changing the tubing solved the problem ??

[briscoe]

Yes

My constant problem was that in summertime restarting my engine usually required priming the bulb. Not anymore. Changed all water tubing and the issue went away. Hot days, no problem. 7/32" ID (5.6 mm)