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PENDANIA
PENDANIA

Posted: Mon Jun 11, 2012 5:13pm

Post Subject: GEARBOX MALFUNCTION

A PARSONS MARINOMATIC REVERSE GEAR BOX FITTED TO A FORD WATERMOTA IN A FREEMAN 26 OF EARLY 60'S VINTAGE , REFUSES TO COME OUT OF FORWARD DRIVE WHILE THE ENGINE IS RUNNING , IT DOES COME OUT OF REVERSE WHEN RUNNING , & GOES INTO BOTH FORWARD OR REVERSE WHEN RUNNING , I HAVE SLOWED THE TICKOVER SPEED DOWN AS FAR AS POSSIBLE - TO NO AVAIL , ALSO CHANGED THE ENGINE OIL AND FILTER ELEMENT , TICKOVER OIL PRESSURE IS 45PSI , ( STATED BECAUSE THE GEAR SELECTOR TURRET HAS AN ENGINE OIL PRESSURE FEED & A RETURN TO THE SUMP , )WHEN THE GEARBOX IS 'STUCK' IN FORWARD DRIVE - SWITCHING OFF THE ENGINE WHILST PUTTING LIGHT PRESSURE ON THE GEAR LEVER - NEUTRAL IS ENGAGED BEFORE THE PROPSHAFT CEASES TO ROTATE , THIS OCCURS AS THE OIL PRESSURE DROPS BELLOW 40PSI . I REMOVED THE RETURN PIPE TO THE SUMP & DISCOVERED THAT ENGINE OIL ONLY FLOWS OUT OF THE TOP OF THE GEARCHANGE TURRET WHEN THE GEARLEVER IS ACTUATED, I ASSUME THAT THE DETENT MECHANISM IS POWERED BY ENGINE OIL PRESSURE RATHER THAN SPRINGS ? IS THE PROBLEM LIKELY TO BE TOO HIGH OIL PRESSURE OR WORN OUT PARTS , I ASK THIS BECAUSE THE OIL FILTER ELEMENT IS ACTUALLY DESIGNED TO FILTER DIESEL , THE ORIGINAL OIL FILTER ELEMENTS ARE NO LONGER AVAILABLE , I PRESUME A FUEL FILTER IS FINER ? I CAN OVERCOME THIS BY CHANGING THE ENTIRE ENGINE OIL PUMP FOR A LATER ONE FITTED WITH A SPIN-ON CANISTER OIL FILTER ( MK.111 FIESTA 1.1 )

Tony-B
Tony-B

Posted: Mon Jun 11, 2012 6:33pm

Post Subject: GEARBOX MALFUNCTION

I can not answer your question because I have never come across that box before but the Lister LH150 hydraulic box of similar vintage uses oil pressure to give reverse and neutral and no oil pressure to give ahead. This is so that in the event of oil pressure failure the box will stay in ahead so you can get the boat back to its mooring. Seeing Parsons are more usually associated with larger , commercial type boats it would not surprise me if it is not the same. I think that you need to confirm that the engine oil pressure really is 45 psi but please note that many engines would have an oil pressure of about 60 psi when new, hot and revving. I do not believe that the filter is not obtainable but I do believe that the likes of Halfords would not stock it. Try a decent motor factors. You certainly should not use a diesel filter because the small pore size means that it will block and then the pressure differential valve in the filter head will open and pass unfiltered oil around the engine. The best help I can give is to advise that you contact these people: http://www.parsonsmathwaymarine.co.uk/parsons_en gines.htm Tony Brooks

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