The numbers were exactly where you said they would be, Albeit it took a bit to uncover them, the cowling has some surface rust on it, so I had to use a piece of steel wool, Mineral Turps and a magnifying glass to be able to find them. Without following where you said they would be there was no possible way I would have found them.
Model No. 80102
Type. 0233-01
Code. 74071803
A Link to any manuals and details regarding year of manufacture etc. would be appreciated.
The engine was made on 18 July, 1974. Allowing shipping time to Australia, it was probably on a mower by the end of 1974.
It is 8 cubic inches displacement, or about 135 cc (the 8 cubic inch number is rounded). It is of the first design generation after Briggs adopted the modern model number system, it has a horizontal crankshaft and a Vacu-Jet carburetor, with plain main bearings, and a rewind starter.
Hi Watson, and Grumpy, Well this machine of yours, really puts the cats amongst the pigeons... It clearly shows, that is if Grumpy and I are correct in our assumptions,...that is, allowing roughly 6 months for delivery of the engine to erection of the machine in the SB factory at Thebarton. your machine is the earliest 17" twin rail Scott Bonnar we have seen on the forum, since my joining the forum in 2005....and it is a Scott Bonnar Model 45 "Craftsman".
To prove this theory, we need some 'provenance', that is, evidence that this machine was erected with this engine in place "as original fitment"...Have you spoken to the original owner re: the purchase date or perhaps a receipt....If so, this is a very important machine for the archives...and to all aficionados of the Scott Bonnar brand...it put the date of the introduction of the twin railers back by 12 months....or that the engine was not fitted for well over that period... It would be fabulous to know the exact provenance of your machine. Watson, many thanks for posting!
Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member. Kindest Regards, Darryl
Hi Deejay, I will need to try & chase this up, I am not sure how successful I will be as I purchased it in about Oct - Nov 2014 off Gumtree. The Gentleman I purchased it from is local so I will try to contact him to see if he has any other details. I will let you know when and if I manage to contact him.
Hi Deejay & Grumpy I managed to get hold of the gentleman I purchased my SB from, unfortunately he was not the original owner of this craftsman. He has had it for the last 15-20 years and unfortunately did not get any paperwork when purchased from an elderly couple. The only info that I can really pass on is that he has not replaced any major components since he has had it, but obviously that does not provide the info required being that this is not proof that this was the original engine. It sounds like it is but unfortunately no documents to prove it.
Deejay is currently unable to reply and as such I will respond on his behalf as I know he's really keen on this topic and just so you don't think he is ignoring you.
Thank you for the follow up and sadly this won't give us any proof nor leads to continue with.
Once again on behalf of the ODK Team, thank you for your efforts in trying as sometimes you never know you could get lucky and correct a major fact within a myth. Something we love to do here.
Cheers, BB.
I live a 24 Hour lifestyle, but every now and again I seem to fall asleep, well at least that's what my wife tells me.
I picked this machine up today, looks very original to me ( chain case and deflector plate have been re painted or replaced as well as engine side of cutter clutch). Engine dates as 75. Not sure if this ads any further information to the topic.
Thankyou 
