As an owner of a 1991 vintage Perkins
4108 I often looked at the orginal "bug catcher" air filter (not a filter, just something to keep bugs from being sucked into the engine) and thought that can't be good for the engine
- dust on the boat means dust into the engine
Anyway, I found a K&N filter on their website, and with a little hose and a few parts
for a PCV system from the local auto parts
store, I rigged this up. I am not putting the model number for the filter since so many Perkins
variations are out there, but just take off the old air screen
and measure the intake manifold diameter and go to the K&N web site. I drilled the hole in the top of the K&N filter small so the PCV elbow
would press fit in and stay without having anything inside to potentially drop off and get in the engine.
50 hours so far and seems to work very well, no oil
vapor in the engine room and a little quieter as well as filtered air for the engine. Total cost about $40.00 US. $30 for the K&N filter and $10 for hose, clamps and elbows if you don't already have them in the spare parts bin.
I've seen other solutions, but this one seems simple and works.