There is a problem appearing in Rotax 912 engines with flickering oil pressure. Three aircraft at my home airfield at Boonah had the problem.
Rotax Australia has appeared, from statements to me by owners, to be somewhat unhelpful in this regard telling the owners the only problem is at Boonah when in fact there have been other reports around Australia of the same problem. Owners have been told all sorts of very expensive fixes including "buy and install a new oil pump"
There are two very experienced engine guys on the field at Boonah and to them the problem is not unique, and easily fixed. The problem is just a weak relief spring (probably a bad batch of outsourced springs), and is easily fixed with some shims. The Rotax factory actually have a shim kit to fix this problem, but people locally have been told to spend bulk dollars on a new oil pump.
One of our members (with air force hydraulic training and experience) and in consultation with one of our very experienced mechanics, fixed his problem by going to the local hardware store and buying a pack of small stainless steel washers to use as shims. Two little washers fixed his problem.
( I will ask M. and B. if they will write a technical explanation to post here)
