PRM 260 gearbox

[Shalder2020]

PRM260, 2:1, gear box,
On occasion the shaft will remain turning slowly in the ahead position when the gear selector is in the neutral position, the shaft can be stopped by hand but will start turning when released, (safety police can remain quiet), No other symptoms, oil changed (15/40 engine oil), no noise, temperature fine!

 

[Plum]

PRM260, 2:1, gear box,
On occasion the shaft will remain turning slowly in the ahead position when the gear selector is in the neutral position, the shaft can be stopped by hand but will start turning when released, (safety police can remain quiet), No other symptoms, oil changed (15/40 engine oil), no noise, temperature fine!

The drive is engaged by two multiplate clutches that run in the oil (one for forward one for reverse). In neutral all the plates are held apart so in theory, no drive. However, the oil between the plates can transmit a small torque which is usually less than the friction in the propshaft bearing and drag on the prop and easily stopped by hand. The torque transmission through the oil will be greater when the oil is cold (thicker) or if an oil with a higher viscosity than specified has been put in. Is the boat in the water? Have you got the correct oil spec? Is the oil hot?

Www.solocoastalsailing.co.uk

 

[Shalder2020]

Castrol 15/40 multigrade diesel engine oil, as I said in my first post the temp is fine, I am aware of the workings of marine gearboxes, the bit I find odd is that the problem is intermittent, hot or cold?