Volvo D1-30 RW Cooling Injector Elbow

[CPD]

My knowledge of marine exhaust systems is not great.

My Benny 345 is fitted with a Volvo D1-30. I have had inlet blockage problems recently and so have purchased a NASA exhaust alarm., I am working out the best place to site the thermocouple probe thingy.

I am presuming that what I have photographed is the water injector elbow, which in my mind is the bit most susceptible to failure (from within).

2 questions :

1. How far downstream of the injector elbow should the temp probe be sited ? (NASA says 150mm I think). Surely it isn't an absolute temp I am after, but a relative (ie I don't want it to rise above whatever normal is where the probe sits). What have you done ?.

2. Am I right in thinking that the elbow fail mode is gradual ie rusts, blocks, temp goes up ?. Is a stainless replacement a good preventative or a waste until it happens (engine is relatively low hours) ?.

Sorry, I seem to be musing out loud ..........

Thoughts and comments appreciated ........

 

[Tranona]

When they do coke up it has little impact on water temperature, but affects the running of the engine. Best way to keep it good is to always run the engine under load and make sure it gets up to temperature. Don't think anybody makes a stainless replacement - and stainless is not a good material in this application which is why the original is cast iron.