Latest on Carb Floats?

I am also curious about this.  Seems there is still a problem with the replacement floats with dimples (861-188), and a newer PN 861-189 available except this time Rotax is charging full price for them, no discount.

Ed, how have the new ones worked out for you?

What's the latest guidance for checking these?  It's still "every 200 hr. (or annual check)" as specified in the LMM (Latest edition Feb 2015).

This is the standard check, and only once has it ever been recommended to check more frequently.

In March 2015, the SB-912-065 came out and it instructed:
'Carry out this inspection of float buoyancy of the engines listed in section 1.1.[A LIMITED RANGE OF SERIAL NUMBERS], according to the instructions in section 3 periodically after each 25 hours of operation, but at the latest after 60 days.'

That was not a general instruction for all engines, but only for that limited range suspected to have bad floats. It also specified: 'The inspection [of that limited range] must be continued even after a replacement of the float, until new and improved floats are available. Only from this point of time the periodic inspection can be stopped.'

The float part number at that time was 861184.

March 2015 also saw the release of SB-912-067, which advised that ALL 'floats with the part no. 861184, which have not been marked' (since july 2012) were to be replaced with 'marked' 81184 floats (one or two dots).

In July 2016 asb-912-069 came out - again aimed only at a limited range of serial numbers, and it instructed the use of 861185 floats to replace floats 'in the limited range affected by the ASB' (Note that this was not a general call for replacement of all 861184 floats, as the majority of them were perfectly good).  861185 did in fact replace the 861184 in production that year...

Finally, in May 2017 the SI-912-029 is released offering 861188 floats. These are specified in the SI as replacements for 861185 floats.  These floats actually have a substantial design change from 861184/861185.

New part number 861189 floats have recently superseded the 861188 but only due to a change of float suppliers. (Not a change of design, there are no known issues with 861188 floats!)