DF140 temp alarm only at idle

[aquamort]

Hey all,

I just took my boat out for the first time in 6 months and was just stuffing around in my local river crabbing. Whilst stuffing around with the pots and the engine idling an alarm would sound, the engine cut out and temp light would illuminate. I can turn key off and start up immediately no problems. It did it about 3 times, only at idle. Fine at speed. (I don't think engine is actually getting hot?)

Pisser pissing well. Has new type engine holder. Replaced engine anodes about 6 months ago.

Checked previous threads and saw similar problem that turned out to be sensor on rectifier? (2015 thread) Also idle speed too low (mine seems fine).

Any recent similar problems/solutions?

Cheers

[Moonlighter]

6 months with no use - give yourself an uppercut! LOL!

First thing to check is voltage - we all know how sensitive these motors can be to low voltage so remove and clean battery terminals, load test, check cables for corrosion, charge batteries fully.

Next is impeller. They go hard without regular use, even though they may seem to be pumping Ok. Replace if any doubt at all.

Thermostat would be next on the list at same time as checking impeller.

[artdf175]

What year is your engine?
How long since the water pump impeller was serviced?


Art

[aquamort]

Batteries great....14.6 volts while engine running. Yeah i had some work to do on my boat (glassed in pockets, re-flowcoat and flek) and it always takes longer than you think!!

Its a 2008 model. I had the water pump apart maybe 8 months ago? Impeller was still soft. Blades curved but am lead to believe they do that these days?

I just ran it on the muffs for a good 20 mins with no problem at all. This leads me to think its some sort of flow problem. I hardly ever just idle around so never experienced it before.

[Moonlighter]

I would replace the impeller and housing. If it stayed curved when you had it out 8 months ago, then its likely worse now.

If you bend the vanes over and if theres any sign of splits/gaps opening up where they attach to the centre section, replace it.

You could also do a vinegar flush if you want to remove as much built up minerals calcium etc from internal passages.

See: How to: Cleaning your cooling system with vinegar - The Hull Truth - Boating and Fishing Forum

[aquamort]

Yeah no cracks or anything in vanes. Just had a curve to them.

Interesting about the vinegar! Went through most posts to see if there was anything negative ie: bad on seals or some alloy surfaces....think is you give it a good fresh flush or even a good run on the water afterwards all is good.

I've had motor for years now and never replaced the impeller or housing (they seem to last alot longer then the old outboard impellers!) so i should probably just replace it.

So you do housing and impeller?

[Moonlighter]

Yes, both together. Work best as a pair, important as the mating surfaces need to fit together properly. A tiny mis- shape or warp in the housing can easily compromise the water flow.