OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Scott Bonnar Discharge unit

Hi my name is mark, i am the one owner of a 1968 Scott Bonnar rotary mower 48 model (it has been in the family since 1968). The problem i have with this mower is with the wipec discharge unit, it isn't giving me a spark. does anybody have any of these units or can you suggest anything that could help get this running.

Hi Mark, welcome to Outdoorking.

I'm not clear at this point whether you are saying that your SB48 has the Magister ignition system, which used a round black bakelite object screwed to the cooling air cowl as part of the ignition system. It was described at the time as a Condenser Discharge Ignition unit. If you have one of those, I suggest you read this (rather long) thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=40796&page=1

If you have a Magister ignition system, the first question is whether it is the Magister unit (the round black bakelite object) which has failed, or it is just a fault in the breaker points or the associated wiring. As you will gather from the other thread, if the Magister is gone, that is the end of it: it is encapsulated in a plastic potting substance and cannot be repaired. Even less can it be replaced. If you want to continue to use your SB48, I think you will need to fit one of the conventional magneto ignition systems fitted to later SB48s. Meanwhile preserve the original ignition system however: complete Magister systems are rather rare, and should be of interest to collectors.

Hi Mark and welcome to the forum. It's always nice to have another Scott Bonnar owner on board.
Mark, I am aware that the SB Model 35 Series 2 had a Wipac Magister fitted, but I'm not sure that the Model 48 did...Could you please post a pic of your machine....It will be great for the archives.

Once again, to OutdoorKing.

Hi guys,

Thanks for your advice, I have taken off the fly wheel and the points and coil are ok, no problems there. To give you more information on the Scott Bonnar my Father bought it from Clyde Industrial Park on 25th January 1968 the engine number is 201-19137 and the model number is 48 � 04038. My Father in his collection had the original sales brochure and owners manual and even the newspaper advertisement. In the paper work there are two pages on the servicing the wipec Magister unit which is the round type. The photos in the sales brochure show the round Wipec Magister unit however on my mower at some point this was a problem and was changed and now it has a cylinder type unit. Please see attached photos.

Thank you, that has confirmed a couple of very interesting things. First, your early Model 48 came with a Magister on its Scott Bonnar 201 two stroke engine. Our archives showed that the early Model 48s could be bought with SB201 engines, but we did not know for sure that those engines had Magisters. My understanding was that the Magister was added to the 201 engine late in its life and I have hypothesized that it stayed until the end of production of that engine. Now my hypothesis has survived this first test of its validity. The second thing that has been demonstrated is that there was a service replacement for failed Magister units, and you have now given us a picture of one. This is entirely new information for our archives. Can you give us more information on that replacement (the cylindrical unit) please? More pictures, details of its label and any other markings, where it was bought, what it was called, etc?

Do you still have the original Magister unit? If so, could you post pictures of that too please?

We would like to see a copy of the 2 page servicing instructions for the Magister....this would be really nice for the archives.

Hi Grumpy and Deejay,

The service replacement cylindrical unit would have been fitted at Hopkins Mowers at Rydalmere in Sydney NSW. The only marking on the unit is on the base which is it was made in Australia by PHILIPS. I have taken the mower back to them and they just shake their head and say No, I talked the owner and he said he vaguely remembers these mowers however he has thrown out all these years ago. No I don�t have the original Magister unit. I have attached the 2 page servicing instructions for the Magister unit. I will take some more photos in on the weekend and upload them for all to see.

My Scott Bonnar

I think one of the most helpful things we could learn, would be the Philips Australia model/product number of the Magister replacement module.

blown572door, do you know where that replacement for the Magister came from, and can you post detailed pictures of it please?

And if your name refers to a Chevy, what kind of blower is it?

Hi Grumpy and Deejay,

No I don�t know where the Magister came from other than it was supplied and fitted at Hopkins Mowers at Rydalmere in Sydney NSW sometime during the 1970s. There are no other marking on the unit other. Were the service pages of the Wipec Majister unit any use to you? Please see attached detailed photos of the unit I hope it helps.

Please see attached

Please see attached

Please see attached

Does the last picture mean that the end cap can be removed from your Philips replacement module? If it can, would you mind posting pictures of the interior parts? We have a circuit diagram for the Magister, but do not have component values because the Magister modules were potted with liquid epoxy, which conceals the details. If we can get component values for the Philips one, that would be a useful step toward identifying the approximate values of the Magister ones.

By the way, you can attach up to 10 pictures to each post - there is no need to start a new post for each new picture. Also, if you use the fifth icon from the left at the top of the posting window (the one that looks like a pressure spray can with a blue arrow beside it), your actual pictures will appear in your posts, without the reader having to click on anything.

Thanks for your help in this - we are getting more information on the Magister all the time from your posts.

Thanks for the tips, No is does not open from the Philips end this is sealed

Your 4th picture seems to be showing the interior of the black cylinder containing the Philips module. Can you clarify just what it is a picture of please?

Thankyou very much for posting the magister info pages...any info we can glean is excellent for the Magister archives...

Hi Grumpy,
Yes the 4th photo is from the top of my discharge unit. I will try and take more photos next weekend and post them.

Hi Guys,
Thought you might find this interesting. On my Scott Bonner 48 both handle hinges have cracked,This looks like a design fault i wonder if anyone else has had the same problem. I ended up getting 2 made at the local Tafe. If I get time over the weekend I will try an take more photos of my discharge unit