Briggs and stratton 14.5HP OHV engine

Any chance of a pic?

There will be some way of stopping it coming loose, sometimes as simple as the nut being a tight fit on its thread. Were they easy or stiff to adjust? .

Steve

If there is a star or torx hole, with a nut around it, then the star is the adjuster (winds into the rocker arm) and the nut locks it in position against the rocker arm.

Take it all back. I have just been looking at an illustration of the engine on empartweb:

It appears that the adjustment is in the middle of the rocker arm ? So it may well be that the adjuster nut is what is known as a stiff nut and should be quite tight on its thread, that is all that stops it changing adjustment, Vauxhall Vivas and chevettes had the same sort of system.

In message , Mrcheerful writes

Are you suggesting the OP should scrap it then?

The viva engine was a pretty good lump for its time, ask Bill Blydenstein. In addition it was incredibly light, any average man could pick up the engine complete, try doing that with a Ford cross flow! I raced one for several years without rebuilding it, the engine was bullet proof when properly screwed together, that engine is still running 24 years later and not even the head has been off and bear in mind it was revving to 6000 with an extremely lary cam.

Lots of engines used the nut in the middle system including Ford V6s and V4s