A really important test of two stroke engines is the crankcase vacuum and pressure test, as air leaks through crankshaft seals, intake boot, cylinder gasket, decompression valve, impulse tubes etc can cause them to run lean leading to premature failure of the engine.
To perform a vacuum and pressure test of the Husqvarna 372 XP X-TORQ chainsaw engine, the intake needs to be blocked off, and the exhaust blocked off, and the test can be performed using the impulse hose.
The intake boot in the Husqvarna 372 XP X-TORQ has a rubber tongue that projects into slots in the carburettor throat, part of the strato engine.
Above, Husqvarna 578-09-56-01 intake block off adapter for the Husqvarna 372 XP X-TORQ. The open end of the ‘tube’ mates with the rubber intake boot, and the recess accommodates the tongue mentioned.
These have been proven impossible to buy in Australia, I have wasted so much time with local Husqvarna and their dealers… enough I would be dissuaded from buying another Husqvarna (I have a genuine 120 MkII). One dealer suggested this might be an “authorised dealer only” product. Whilst online shops elsewhere advertise the tool, I have not found one that ships to Australia (at a reasonable price).
So, to improvise.
I intended turning one out of a piece of 40mm aluminium round,,, but elected for an easier way, even if the tool was a little less convenient to use.
Above, the DIY adapter set. The piece of tube is about 12mm length cut from a short piece of 28mm OD, 25mm ID 6063 tube purchased on Aliexpress. The steel plate was cut of some scrap and drilled to suit. A couple of M4x25mm screws and some pieces of 2mm Nitrile Rubber for sealing intake and exhaust complete the set.
Above, the improvised intake block off.
Above, another view of the adapter set.
It is a bit fiddling to set the tube and rubber in place, I expect the OEM tool is more convenient. It occurred to me later that to put a fairly tight elastic band around the screws and tube might hold them aligned and make the fitting job easier.
The vacuum and pressure test is performed using the impulse line (the rubber tube to the right of the adapter. The adapter worked fine.
Note this is a non-electronic (other than breakerless ignition), non-autotune carburetted engine, albeit with stratified intake.
The beauty (not) of modern engines is that they will automatically compensate for air leaks, up to a point, well more than air leaks, blocked air filters etc. The end user does not have the warning signs of problems like unstable mixture settings, mixture needles way out (except models complying with anti pollution laws that prohibit adjustable mixture).