Tohatsu TLDI MD90B air injector seals

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. The boat has been laid up since last year, and earlier this year I removed all the injectors and sent them away to be cleaned and tested. They have been removed and installed at least twice before.

I'm now finding I cannot reinstall the air injectors (actually I've only tried one so far) because the white Teflon(?) seal has expanded and now tries to ride up over the lip of the groove it's supposed to sit in. After reading about these seals I'm wondering if I should replace them, and I'm worried the one I have tried to re-fit might be damaged now anyway.

Looking through the Tohatsu parts catalogue gives me no part number for these seals, and I also see I would need some kind of tool to re-form (compress) the seals back to size small enough to install into the head, and it seems that needs to be done quickly after compressing them.

Are these parts available for/from Tohatsu, and if not, could I use the part available for the similar Mercury Optimax injectors? Or even some other brand of injector seal that has the same size? My injectors measure 9.95mm diameter, I assume the seal would me nominally 10mm or even slightly bigger? I need to find a source for the seals and the tool to compress them, any suggestions?

Cheers,

-phil

Item 13 is the air injector. There are 2 o-rings (13-1 and 13-2), and a compression seal (18). All are available.

Thanks Paul,

I'm not sure this is correct, or at least it's not what I mean. The parts that _are_ available are the two o-rings and the compression seal, but that doesn't include the white Teflon sealing ring. Working from the injector outlet port that faces the piston, the order is:
1. Teflon seal - not listed in the parts catalogue
2. O-ring - part 13-1 (I have ordered and replaced these)
3. The injector body
4. O-ring - part 13-2 which seals into the air-rail (I have ordered and replaced these)
5. Compression seal - part 18 which seals with the injector insert (I have ordered and replaced these)



These white Teflon sealing rings need to be expanded using a 'special' tool to fit them, and then need to be compressed back to size using a different tool. It seems to be a fairly common operation in car injection systems, and google shows me a variety of hack ways to fit and compress them without the 'proper' tools. I see sets of parts available for Optimax injectors, that include these Teflon seals, for example:
https://www.ebay.com/itm/Marine-Mer...it-Orings-Teflon-Seal-OEM-parts-/173361462695
The tools are also available for Mercury: https://www.airinjectors.com/specialtools.html

Cheers,

-phil

Dunno. In my place, I would probably do the complete injector, since the OEM part is not available separately.

OK Thanks Paul, appreciate you taking the time to reply. I have managed to get three re-installed in one of the engines, by compressing the sealing ring with a cable tie and cooling the whole thing down in the freezer.