GunnaDo Posted July 11, 2017 Report Share Posted July 11, 2017 I have a PRM 150 D2 (on a Beta 43) which clunks quite badly when selecting gears. To be fair it has done since I bought the boat in 2009 but is getting worse now. I tried the drive plate but that is OK and the engine mounts are fine. I'm going to have to go inside the beast! Does anyone know whether it is possible to rebuild the mechanical side without upsetting the hydraulic pressures? I suspect that the clutch plates are badly worn on the splines. (I am a mechanic of some 40 years but have never had anything to do with hydraulic boxes) Link to comment Share on other sites More sharing options...
Tonka Posted July 11, 2017 Report Share Posted July 11, 2017 Have just sent you a prm 150 manual via pm. hope it helps Link to comment Share on other sites More sharing options...
RLWP Posted July 11, 2017 Report Share Posted July 11, 2017 Most of the PRM gearboxes with plate clutches make a terrible clunk when they engage. It's in the nature of the beast Richard Link to comment Share on other sites More sharing options...
MtB Posted July 11, 2017 Report Share Posted July 11, 2017 Your engine tickover speed is probably too high. Link to comment Share on other sites More sharing options...
RLWP Posted July 11, 2017 Report Share Posted July 11, 2017 8 minutes ago, Mike the Boilerman said: Your engine tickover speed is probably too high. Today's reassurance was to an owner with a PRM 260 on a JP3. It also clunks Richard Link to comment Share on other sites More sharing options...
MtB Posted July 11, 2017 Report Share Posted July 11, 2017 The PRM150 on my 40ft MB used to clunk gently when tickover was as low as I could get it. If tickover adjustment drifted up even slightly, the clunk got HORRENDOUS. Link to comment Share on other sites More sharing options...
Tacet Posted July 12, 2017 Report Share Posted July 12, 2017 18 hours ago, RLWP said: Most of the PRM gearboxes with plate clutches make a terrible clunk when they engage. It's in the nature of the beast Richard I'm surprised. No dogs or gears are brought-in (on the hydraulically engaged boxes) as the take-up is through the multiplate clutches (if I understand correctly) so what is that clunks? Not doubting - just asking. Link to comment Share on other sites More sharing options...
Chewbacka Posted July 12, 2017 Report Share Posted July 12, 2017 20 minutes ago, Tacet said: I'm surprised. No dogs or gears are brought-in (on the hydraulically engaged boxes) as the take-up is through the multiplate clutches (if I understand correctly) so what is that clunks? Not doubting - just asking. The clutch tends to snatch shut very quickly sending a shock wave through the boat. Link to comment Share on other sites More sharing options...
mross Posted July 12, 2017 Report Share Posted July 12, 2017 Is OP going straight from ahead to astern? I always pause in neutral unless an urgent stop is needed. Link to comment Share on other sites More sharing options...
RLWP Posted July 12, 2017 Report Share Posted July 12, 2017 48 minutes ago, Tacet said: I'm surprised. No dogs or gears are brought-in (on the hydraulically engaged boxes) as the take-up is through the multiplate clutches (if I understand correctly) so what is that clunks? Not doubting - just asking. All the plates are on splines, which have backlash Richard Link to comment Share on other sites More sharing options...
Tacet Posted July 12, 2017 Report Share Posted July 12, 2017 3 hours ago, RLWP said: All the plates are on splines, which have backlash Richard OK. Does the the less-free clutch not have sufficient drag to take-up the backlash in one direction? On a motorbike with a multi-plate clutch, a crunch when engaging a gear is usual - but not when subsequently letting the clutch in. Link to comment Share on other sites More sharing options...
Col_T Posted July 12, 2017 Report Share Posted July 12, 2017 4 hours ago, mross said: Is OP going straight from ahead to astern? I always pause in neutral unless an urgent stop is needed. I thought one of the advantages of a PRM 150 is that, being a hydraulic box, you could go direct from forward to reverse, or vide-versa - am I wrong?? Link to comment Share on other sites More sharing options...
mross Posted July 13, 2017 Report Share Posted July 13, 2017 You can when needed but it adds wear to the two clutches. It's best to let the engine speed drop to idle, go into neutral, pause to allow prop and shaft to stop and then into ahead/astern. Link to comment Share on other sites More sharing options...
Col_T Posted July 13, 2017 Report Share Posted July 13, 2017 Okay - thanks for that. Link to comment Share on other sites More sharing options...
GunnaDo Posted July 16, 2017 Author Report Share Posted July 16, 2017 Thanks for the above and apologies for tardy reply. I only boot up the laptop every 4 days or so. Tickover was first thing I looked at and is approx 750 rpm. I never go from fwd to reverse in one go! I agree that hydraulic boxes are renown for being quiet and smooth whilst mechanical boxes are clunky otherwise why complicate things. Thanks for the manual, I'll get to look at it when I get back from current cruise in August or should I say IF! Link to comment Share on other sites More sharing options...
Featured Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now