My Perkins 4.236 finally told me it was clogged up by refusing to run at normal revs and lacked the normal power this big engine has.
This long article explains how the whole cooling system was dismantled, cleaned, and restored the power of my old engine. If your engine lacks power and tends to overheat, read this article and fix it yourself.
2380 words 13 pictures. Price for this article $10
RESTORE YOUR ENGINE COOLING SYSTEM