my 76 2qm20h has the same issue as the OP's, among many others, and am grateful for the answers provided. I'll be going to braided stainless when I do replace that
oil line. In the meantime, if I could, I'd like to also ask about the threads on the 2qm20's zincs. When I bought the
boat, there was a little container aboard with 5 zincs in it, only one of which was in the original pkg, labelled 27210-200300 (screw size 20X30mm). The others were all in as-new condition, so I assumed they were all the same. I set-to replacing the old (completely corrodedx3) ones. To my dismay, only
one would screw into place. All four others jammed in about 1.5 turns. I've learned to be ginger with any screw-ins, on any engine, so stopped whn resistance became obvious. On closer
inspection, it seems the threads of the remaining 4 are coarser than the 1 that glided in. The pkgd zinc 27210-200300 was one of those with the coarser threads. I cannot find any reference online to this discrepancy.Any
advice? (actual fine-thread - possibly metric? - part numbers?)
Have four or five questions re that engine but will leave it at that for now. pict'd is the 27210-200300, with the 'coarse' thread.
thx in advance. (to be honest, I only tried the zincs in 2 of the 3 easy spots, fwd on the engine... if the zinc fitting on the aft-end of the
2qm20 has different threads I'd be dismayed and very, very surprised.