OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar 45 Restoration - newbie

Hi all,
I've just picked up a Scott Bonnar 45 from the misses old man where it was sitting out in the shed unused for last 10 years.

I've no experience with cylinder mowers but always wanted one and so happily took it off his hands and looking to refurb it. Thus have the engine in a number of parts at this stage and after some advice.

The carby is stuffed so i need a new one of those but cannot find one on the internet anywhere... its a 3.5HP Briggs and Stratton and i found the following number on the cover shield: 60202 0198 01 6902053. No idea what that tells me other than the 60202 seems to be a model number but from all other internet posts it appears under 2 and 2.25HP? I also need the carby springs and new air filter and a few other bits and pieces. The blades are also fairly warped and no doubt will need to be straightened out and sharpened.

Wondering whether its worth going through the hassle of new parts for the what im assuming is the original engine or as per my local mower shop assistants advice - buy a new motor.

Any help would be greatly appreciated.. will post some pics now also

photo1

Hi danebb16,

Well that's a bit of a curly one you've got there as it's had some work done on it by a previous tenant.

The number you've quote is a 60202 which would be a 2 Hp motor. The 6902053 correlates it to being built on the 5th of February 1969. Now here's the problem, it is now a Black motor with a much later Briggs sticker on it when the engines of that era in the 2 Hp range came in Silver / Grey finish. Now this could be one of two situations and the first being that the motor was repainted sometime back as it's showing its age and the other is that that the cowling has come from the original motor and been repainted to suit the replacement and an updated sticker was put on it.

Honestly without knowing it's true history it's more of a guessing game.

Just for the record, if the motor is the original unit then it would date the whole 14 inch mower as being built around July~August of 1969


So, what you need to tell us is what you ultimately want as an end result ?

To restore it back to it's original state or just want a working mower to use ? if it's the latter then buying a brand new "Chonda+ (chinese copy Honda) for a cheap price and installing it is probably your easiest and cheapest option in the long run.

If you want to go down the restoring path we can certainly help you with that option too.

Can you supply us with some close up photos of the drive train that's located in behind the chain case. Good close clear shots will help us evaluate what needs to be done there and give you a better financial position that you'll be facing.

Cheers,
BB

Thanks BB,
It has definately been painted black and was originally silver and as you say must have had the new sticker put on following this work.

My first preference is to restore to original but if this is going to be cost prohibitive then i will settle for a chonda do over and maybe do the engine up slowly for an eventual changeover.

For the life of me i cannot find a replacement carby for this model.. only luck ive had is the kit to replace the gaskets, needle, etc.Also how do i find the parts list for this motor?

I'm doing all this from ipad so will try to upload the picture of what lies behind the chain case now:

thanks again

Hi again,

Well My first instinct was correct in thinking that it was the original engine that has had a modernisation to it's look. It was probably sold second hand many years ago through a shop and they wanted to fetch a few more dollars with it looking more up to date than the silver engine which does period date it to the 1960's

Grumpy would probably have scans of the carby break down on file to provide. I do have them myself but they are in a 8 inch thick Briggs & Stratton book which makes it quite hard to scan.

You are pretty much spot on regarding replacement parts for those early carbies, all there is are the basic diaphragms and gaskets etc. You might have to go to a lawnmower shop that has been going for many years as they manage to collect a lot of this older stuff just incase they need it for a repair job themselves. The more modern shops just won't carry that sort of stuff.

I must admit that the photo you've uploaded is a tad hard to comprehensively diagnose, some real close ups of the actual sprockets individually would be much better, but just a quick look tells me that there is normal wear on the cutter sprocket but whether it requires replacement will depend on seeing it in a better shot.

BTW it's good to see someone that wants to do a factory type resto, but everyone does have their own priorities and expectations I guess.

As far as all the actual mower parts are concerned, most of it is still available as spare parts but carby stuff is what writes many of these engines off to scrap.
I have one here that has a totally broken (snapped) carby and as such that's now part of my bone yard.

Hopefully Grumpy will chime in with some visual help here.

Cheers,
BB

BB,
Hopefully those photos show a bit more detail on the condition of the sprockets.

I have a new action plan - will purchase a carby restoration kit and see if i can get it running smoothly with some TLC. If I can then I'll disassemble and restore to its former glory, if I cant then a replacement motor to get the mower functioning will have to do.

If the third digit in the Model number is a 2, it has Pulsa-Jet carburetor. Here is some information on them, for a start:



Essentially, the things likely to cause poor running are dirt/gum on the screen at the bottom of one of the tubes, or in a jet, metering hole or passage, or deterioration of the fuel pump diaphragm. The page from the manual posted above outlines the cleaning process. Figure 51, at the bottom of that page, shows you how to disassemble the fuel pump to check its diaphragm. If it has become moderately stiff, or the flap valves do not lie flat against the metal surface, you need a new diaphragm. I suggest you disregard Figure 46 for the moment: the spiral is not likely to be a problem unless the carburetor has been abused.

Hi danebb16,

Well I see Grumpy has chimed in as anticipated and that's great.

As far as the sprockets are concerned they'll live on for the time being as they aren't too far gone and are only showing average wear, so that's a good thing as far as spending money is concerned at this stage of the process.
Honestly I'm sure you'll be able to get that carby going and end up with a fully running Scotty in no time.

Cheers,
BB

Gents,
See the main issue with the carby in the top left corner of this pic. The weight on the top attaches via a brass pin to what i'm assuming is a butteryfly type valve to increase/decrease petrol volume. The problem is that the brass has come loose from the weight and therefore does not grip and turn the valve correctly. Hence why a previous owner has used what appears to be a type of bog to reattach the two.

Does anyone know whether this piece can be removed and replaced? If it is possible its not easily evident how to go about it. I also noticed Gummy that the piece in question is not shown in the diagram?

thanks,

sorry - one more question - does anyone know the part numbers of the spring and wire shown in the pic above? and where i can order these from?

This is what that linkage looked like in its youth, before a previous tenant made improvements:



You need to make it look like that again. Note that the throttle butterfly is operated by a bent-wire link, not some folderol with a "weight", a "pin", and whatever other rubbish that idiot happened to have under his bed.

The part number for the wire link can be found in the Illustrated Parts List, here:

http://bsintek.basco.com/BriggsDocumentDisplay/Z6jmsHVJ1DajI.pdf

If you look on Page 5 of 15 you will find that the wire link is Item 201, and on Page 12 you'll find that the corresponding part is called Link - Governor, and the part number is 260898. I suggest you contact the On-Line store, or a mower shop, to get one - or you can probably get one from a defunct engine.

Similarly the Governor Spring is Item 209, Part Number 260041.

If you want to see what it should look like except with the governor spring missing, try this thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=61875#Post61875