PRM

[dsw]

i have a prm750d and when i put it in forward gear it engages but the engine will not rev up but the engine does rev up when out of gear no problem and when i put it in to reverse it engages and at first it wont rev up then all of a sudden it does and works normally. now this has only happened twice in a few months and only when i have been running for an hour or so and the box is not hot and the oil is on the right level, and lastly it has always clonked when i put it into gear hot or cold forward and reverse and when i say clonked its not aggressive just a clonk,next day was working fine apart from the clonk so what do you think ?

 

[roly_voya]

Sound more like air in a fuel line, are you sure its related to the gearbox not just putting the engine under load?

 

[PCUK]

Is it a single lever control? Could be a fault there!

 

[stephenmartin]

With the engine running it turns the flywheel and the input shaft is constantly turning...only when it goes in gear does it engage the clutch to turn the rest of the gears....

Seems like the clutch assembly...layshafy or output shaft gears....

IS THE PROP FOULED WITH ROPE OR NETS....check this before you rip out the gearbox...

Failing that try http://www.newage-prm.co.uk/ its an old English firm that close for lunch

 

[30boat]

I think the clonk is weird.These boxes engage via two multidisk clutches,one for each speed, that should be smooth on take up.This may not have anything to do with the revving problem.At first I thought it could be a bearing on its last legs but if the casing is not heating up it could be something around the prop or an overtight stuffing box.Check the gearbox oil for contamination though.If you find metal sludge you have a problem.