A quick question for the Yanmar experts

[Ian_Edwards]

One of the bolts which holds the engine mount to the block has worked loose and dropped out over last season. I found its rusted remains in the bilge.
The bolt, more correctly a set screw, is M12, but it’s not the regular 1.75mm pitch, I had one of those on board and it doesn't fit. Looking on the web there are two fine pitch for M12, 1.5mm and 1.25mm.
Anyone know which of the two pitches it’s likely to be?
The engine is a Yanmar 4JH4E and it’s the starboard rear engine bracket.

 

[Eygthene]

If the rusted set screw in the bilge is not impossibly rusted, count the number of threads over a 20mm length and work out the pitch yourself (otherwise remove another good one and use that for the measurement). I usually wrap a clean white paper strip round the thread and holding it tight on the screw, turn the screw inside it. When unwound you should have a reasonably clear set of thread marks and you can easily measure and mark 10 or 20 mm on the paper with a ruler and then count the number of thread marks in that length. Simple division will give you the pitch in millimetres.

 

[moonshine]

Hi,

If you use the Ribs Marine Parts website you can review all the parts for your Yanmar engine, print off the sheets as a ready reference

A

 

[Ian_Edwards]

Thanks, moonshine, the link to Ribs Marine is great and I've identified the part number, so I can buy it from a Yanmar agent. But it still doesn't tell me what the thread is!