Testing KAD32 Supercharger Clutch Serviceability

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Somerset Taz

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Hi Gurus out there. I have had problems with my port KAD32 supercharger engaging permanently - when the engine warms up. I have traced the reason to the speed relay in the black box (it feels quite hot to the touch) and confirmed this by popping it on the stbd engine and replicating the symptoms. (Boat is out of the water.) I've opened up the relay and there is a strong smell of burning and visible burning damage in the vicinity of the S1/31- circuitry. I've ordered a new relay, but I need to locate the cause of the over heating to treat the cause and not just the symptom! I suspect the SC clutch may be on the way out and possibly now drawing too much current - but don't know what the normal current draw is or whether there is an easy way to test the serviceability of the clutch without running the engine. Can anyone help out there please? Many thanks
 
Apologies for the delay in updating all. So fitted new SC clutch and new Controller (port engine). Ensured the SC clutch engages by direct feed before running engine up. Ran engine no SC engagement and no engagement either when in kick down (both actually and using a large screwdriver up against the throttle position sender). No output to the SC plug. Checked all wiring connections for stupid mistakes - all correct - controller connector had 12v at the 15+ and earth at 31-. Then tried the (new) port controller on the stbd engine - no SC engagement. Then the stbd controller on the port engine still no go. Replaced the stbd controller back on the stbd engine - stbd engine SC worked perfectly again. So stumped - if the (new) port controller was actually ok it should have worked on the stbd engine. But why didn't the working stbd controller not work on the port engine. To my mind it seems there is more than one fault here, the new port controller u/s and something else weird with the wiring perhaps. Sorry a bit of a ramble but any pointers gratefully received. Cheers Taz
 
Somerset Taz said:
Apologies for the delay in updating all. So fitted new SC clutch and new Controller (port engine). Ensured the SC clutch engages by direct feed before running engine up. Ran engine no SC engagement and no engagement either when in kick down (both actually and using a large screwdriver up against the throttle position sender). No output to the SC plug. Checked all wiring connections for stupid mistakes - all correct - controller connector had 12v at the 15+ and earth at 31-. Then tried the (new) port controller on the stbd engine - no SC engagement. Then the stbd controller on the port engine still no go. Replaced the stbd controller back on the stbd engine - stbd engine SC worked perfectly again. So stumped - if the (new) port controller was actually ok it should have worked on the stbd engine. But why didn't the working stbd controller not work on the port engine. To my mind it seems there is more than one fault here, the new port controller u/s and something else weird with the wiring perhaps. Sorry a bit of a ramble but any pointers gratefully received. Cheers Taz
Click to expand...
Speed sensor , but before you swap try the kick down sensor by unplugging it the charger should run
 
Hi Paul,

Please don't go!

Many thanks again and I will try this. I take it by disconnecting the kick down sensor you mean the 3 pin connector in the relay box. Also, am I on the right track that because the new port controller did not work on the other engine that it too is u/s? Thanks Taz
 
Somerset Taz said:
Hi Paul,

Please don't go!

Many thanks again and I will try this. I take it by disconnecting the kick down sensor you mean the 3 pin connector in the relay box. Also, am I on the right track that because the new port controller did not work on the other engine that it too is u/s? Thanks Taz
Click to expand...

The kickdown sensor, the part you were tapping your screwdriver too, can burn out with the SC controller. At least mine did and that for some reason knocked out the controller too.
As an aside, to prevent these electronic pieces from future damage from a faulty clutch put in a relay between the SC Controller and the SC Clutch.
 
Hi, was waiting until the end of the season to post a conclusion. My boat is a Bavaria 29 Sport 2005. Short version! New clutch, new controller, original speed sensor and kick down sensor tested -ok. Cleaned contacts (not that they looked like they needed it). I fitted an isolator switch circuit to both SCs with switches in the cockpit. Now when I'm cruising down the Dart from my mooring to the open sea (6kts @1400-1500 revs for 4 miles, I have the SC isolated to stop the clutch engaging and disengaging. Then when ready to speed up I return to idle and switch the SC circuit to on and away we go. So far all's well. Hope that helps. Taz
 
Apologies, I should have added that the first new controller was found to be u/s from the factory. This would explain why it did not work when I tried it on the (good) stbd engine (see my 10th May post). When a second replacement controller was fitted, the port SC with new clutch worked as it should. Regards Taz
 
Another update - sadly!! Despite apparently working well during the season the problem of the supercharger being permanently on has returned. My bespoke supercharger isolator switch works (see above). The boat is now out of the water and the supercharger engages as soon as the ignition is switched on (engine not started) - isolator switch to on. Disconnected the speed sensor - supercharger clutch still engaged. Disconnected the three-pin connector to the kick down sensor - supercharger clutch still engaged.
Removed the speed sensor and it tests ok (1000 Ohms, steel proximity generating voltage etc). (BTW a reminder from my earlier post, I changed the supercharger clutch last winter.)
I suspect the speed controller relay has been damaged (again!) and now S1 is permanently closed when ignition is on. However, in the hope of finding the root cause I'm homing in again on the kick down sensor as the reason the speed controller is getting trashed. Perhaps the gurus out there could tell me if I'm on the right track and if I disconnect the three-pin plug and jump the G2 and G+ pins to the speed controller will this simulate the kick down part of the circuit in non-kick down mode? Or any other checks I can do. I hope the above makes sense. Very many thanks Taz
 
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