2QM20 yanmar

[sfnz]

ok have one that's a great runner and want to keep it that way, noticed the rocker oil feed pipe has corroded where it passes under the exhaust not leaking.....as yet but pretty deeply pitted, question is, is copper ok to replace this section.. welded using eziflow as having a bit of fun sourcing steel tube this size (5mm) and 1/4" copper should sleeve over ok.....thoughts anyone?

[jimbunyard]

Seems a common problem, I think I remember 3 or 4 threads about it in the last year or so.

Don't know what eziflow is, so I can't comment on it as a way of connecting copper to steel.

As far as replacing the line with copper and brass fittings, I wouldn't have any problem with it, as long as the line is attached to the engine so that it vibrates in concert with the engine. Copper line will work harden and crack from vibration.

In the past when I've heard about this, I always wondered why people who have this problem don't just go to braided stainless. Something this small could probably be had for less than Yanmar wants for their not-so-good steel line. Plus they look cool.

Stainless lines are readily available, from hot rod parts stores and industrial instrumentation suppliers. A quick online search yielded this superduty 1/4" braided steel line, 18" long with 1/4" NPT male threads for 27.83...

1/4 In T321 SS Annular Corrugated Metal Hose Assembly With T304 SS Single Braid, AF4750

[zeehag]

i knew that hose as aeroquip hosing in sporty car racing. good stuff. want to convert to this with my boat.

[mooka2]

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.