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TLDI oil in the air rail

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Hello all,

I have a pair of 2006 Tohatsu TLDI MD90B motors on the same boat, which according to the diagnostic functions have done between 150 and 249 hours. I've had the boat nearly 4 years, though it doesn't get a great deal of use. Last year the boat was only used twice.

In the process of diagnosing some poor idling 2 years ago, I noticed a green oil emulsion (the oil is that colour) in parts of the air rail, around the regulator and around the compressed air input port after disconnecting the hose fitting. I wasn't sure if this was some oddity over a long time so I stripped the compressors and air rails and cleaned everything, then reassembled with new gaskets. I ordered compressor piston rings but they arrived too late. The compressor cylinder didn't appear badly scored to me, but I have no experience to go on.

After only about 15 or so hours running last year, I have partly stripped and checked the engines, and I see the oil again, See this video:
https://www.youtube.com/watch?v=1s-ypO6HEr4

Is this normal? Should I be replacing compressor rings and/or cylinder housing?

One point to bear in mind is that I now know I have been using oil that is apparently not DFI rated, as I was unaware (and it seems the previous owner too) of this requirement. Not sure if the viscosity is different and might cause this?

Any guidance would be really appreciated.

Cheers,

-phil
 
You must run DFI oil. While TCW3 will work in a pinch, the full syn DFI is the way to go.
If you have spare rings, hone the cylinder and run them. Can't hurt.
Doesn't look like too much of a problem; likely just blowing past the compressor rings.
 
Thanks Paul, appreciate the help.

A Tohatsu dealer here in the UK has also suggested I check the reed valves, thinking there may be some 'blowback' due to one or more not seating properly. Not sure I understand that mechanism but I will do anyway- I had some idling issues on one engine, and even after swapping essentially all fuel and electrical systems between the two engines the problem remain on the same one, so I was already beginning to wonder about the health of the reeds.

Cheers,

-phil
 
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