OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar Model 45 resto tips

It doesn't lock shafts together, it just locks a clutch hub to a shaft. In effect it locks by friction - once the nut is loosened and the pin is able to slide axially as much as the half-moon cutout allows, it is no longer interfering with pulling the clutch off the shaft. The remaining problem is just rust and/or hardened crud that has built up between the shaft and the hub, obstructing sliding. It is desirable to soften the rust or crud rather than use sheer force to pull them apart, because the latter might damage something.
The traditional treatment for your problem is to squirt a penetrating agent onto the junction between shaft and hub, wait the appropriate amount of time (hours, maybe a day) then wiggle the hub both rotationally and axially for as long as it takes. You said earlier that you are getting a couple of millimetres of movement of the hub on the crankshaft, axially. If you have movement, you can get it off without massive force, provided you soften the rust/crud first. The traditional penetrating substance to use is called Penetrene, and you can get it from Repco (and probably other places as well). Cheaper alternatives like WD40 might work also - my own successes have been with Penetrene, and I haven't had any success with WD40, which is mainly intended for a different purpose.
Just get the penetrant into the joint, then wait as long as possible (I've been known to soak a joint for a week, warming it to about 100 Celsius from time to time, but that project ultimately failed anyway - it was thoroughly bonded together). After that is the hard part: the wiggling and twisting, without applying heavy forces because that tends to jam things up. As long as you have movement between the parts, keep wiggling. The wiggle-room will gradually increase.
When the parts are bonded together (no wiggle movement at all) you use a different process, which I won't go into here.

Thought that I'd get back to everyone and let you know how things went. After 15 minutes gentle persuasion with a soft mallet, I got the clutch off. Part of the problem might have been that the keyway had a section that was fractured. Anyway, clutch is off now and all thats left to do now is contemplate if this is enough of a reason for me to update to a Honda GX100.

That crankshaft is finished. You need to replace the crankshaft or replace the engine. My first question would be directed to Deejay, and I'd ask him whether there is any difference between SB45s fitted with Tecumseh and B&S engines. If there is no difference, you could fit an old Briggs 60102 and have an original engine that happens, as a bonus, to be incomparably better than that woeful Tecumseh. (I had a Tecumseh of that vintage for a long time, and built up a strong dislike.)
If the Briggs engine would be considered non-genuine by the purists, you'd have to choose between getting another Tecumseh from a wrecked mower, or abandoning originality. I suspect you'd still end up with a 60102 - I don't see the Honda having any advantages, if the rumours of loss of quality in recent times are accurate.

supercheap dont stock Septone products any more, you would have to go to mitre 10 or bunnings to get some

Thanks for the heads-up Tezza, I will check them out.

Hi stu45 and grumpy, as far as I know there is no difference in the engine mountings for either the Kirby/Lauson/Tecumseh or the Briggs...though Briggs used a 2.5HP on the 14" and 17" mowers and the 3HP on the 20" mower. The clutch assy on all models is identical. The only chassis difference is that the early Model 45's had a solid engine deck and the later models had the twin rail decking. The engine mounting position was also common to all models.

Re: the Honda G100... it has been replaced in the Honda line-up by a new design and unfortunately probably manufactured somewhere in Asia and not in Japan.
However....some dealers (Honda Power Equipment)may have one or two in stock and these are the more desirable engines.
grumpy prefers the older Briggs engines possibly for originality in the restoration....I chose Honda for functionality .....one pull starting, the spark plug has never had cause for removal in over 7 years of regular use....it's just a great little performer.

That's a great summary Deejay. Also, the early Briggs 60102 is only 2 hp, which may be a bit low. As you said, it is a choice between originality and functionality, provided any Honda that is fitted has the traditional Honda quality rather than something less.

Hi guys, intersting reading as I have had a Diplomat (some say ugh!)for 20 years+ (acutlaly I had 2 andade one good? one out of the two and have some spares)and a 45 for the last 12 months off ebay. I have parts explosion and some portions of the manual for the Diplomat from SB/Rover from way back, but I have NOTHING on the 45. From where do I download the manual? I need to make soem repairs and get it running and cutting like new. Thanks.
PG

PS if anyone has an electronic manual pdf etc and would like to PM me I can be reached on phantomguy@bigfoot.com. Many many thanks.

Phantomguy,

The forum has parts list and manuals area that you can download a pdf file from but you need to subscribe to the area in order to download the file.

Thanks Bruce.
AND
Thanks for warm welcome Deejay in topic thread "Restoring Scott Bonnar 45, 14inch" onto which I seem to have posated in error.
Will post pics later. For time being have listed my both mower details under my signature. As for paying for manual. I don't mind but I have never paid anything on line (eg credit card) and am not keen to start now given that i suffered a huige fraud some years back and still worried due to the horror stories I keep hearing. Some other way to pay for the sub cost?
_________________________
PG
My Mowers:
SB Model 45: 17",3hp, Model No:21339, B&S Model 80202, type 1735-01, Code 82111901
SB Model Diplomat: 17", 3hp Model No:1414, B&S Model 80202, type 0880-01, Code 79110101

Does anyone know where to get -
(a) the Z shaped rod (with fine slide-on spring) that actions the choke piston on the B&S Model 80202 carby. BOTH my 45 and Diplomat 430 ones snapped (they are horrible things that need just the right shape to work smoothly), and I made up one for each from hard wire, suitably burred for a spring stop, but they didn't last more than a season before snapping.
(b) original style cutting level winders (each is different) as the ones I have made up are a bit crude;
(c) a grooming option to retro fit behind the front rollers - maybe on the axle bar- so as to rake up the grass blades prior to the cylinder cutting them (as happens with the more sophisticated models);
AND
(d)has anyone ever fitted different 17" cylinders with more blades than the standard 6 (are they available?) and thinner bottom knide blades for closer cut? On checking I see that me Diplomat 430 has a thinnner knife blade(approx 1.5mm)than the Model 45 (approx 2.5-3mm). Was the original?

if the square key fit nicely on both sides of that break i wouldnt worry about that damage, if it was my engine, but only if the key fit across the damage, but thats me.

Hi PG, Could you please post some photos of your Model 45, and in particular the front roller height adjuster, which I think you refered to as the 'cutting level winders?

With regards to the fracture of the crankshaft, I would definately agree with grumpy....that crankshaft has had it's day.

Re: a teasing rake...yes mate, you can get a genuine teasing rake for the Model 45 Scotty, though not cheap, nor sure about one for the Model 430 Diplomat, but I don't think so.

Re: Again for the Model 45 an 10 blade cylinder reel is available, but at a cost of $$$ plus freight could be worth more than the complete mower and is designed primarily for use on couch lawn.

Re: the bedknife blade, the "thinner" bottom blade does not guarantee a closer cut and in fact can be detrimental as the thinner bedknife can warp more easily. It's the very front edge where the cutting occurs and the minute clearance between the bedknife and cylinder reel.
There is a thread on this topic on the forum, that you may care to read.
Hoping this helps, PG,

You are so attentive and helpful Deejay. What would this forum do without you.

(a)Don't have a decent camera here at the moment but the height adjuster for the 45 is the same as the photo posted by adb on 10/2/10 at https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=16262&page=1. As for the Diplomat 430 it is a black plastic knob with a smaller threaded bore and a separate centre depth indicator cap that goes onto the end of the actual adjusting rod. Any good?

(b)Teasing rake ... yes. I have now seen one on TMS (Turf Machinery Supplies in Victoria) for $199. Ugh! Could almost make one up. Anyone done that?

(c) yes I see at TMS site a 10 blade cylinder is $518 and kit with bearing, screws and bottom knife blade is a about 410 more. Sooooooo expensive! Some other brands for even 30" are around $300! TMS say they are the manufacturer. Right? Or do they get these from China or elsewhere in the world? You would think these are an ongoing item for multiple brands and that there would be a 3rd party product made. Anyone?

(d) Thanks DJ for the advice on knife blades. I saw somewhere (TMS?) about a range of blade thickness options and some bumpf about "closer cut". I will try to find the thread you suggest.

Bruce/Moderator or someone? How can I get the suitable SB45/BS-80202engine repair service manual and pay the sub - but not by online payment?

Hi again Deejay
I cannot locate the Topic on blade adjusting that you suggested. More info/link please?

GRASS DEFLECTOR: Also I would like to know more about the mechanism of, and the positioning of, the grass deflector on the SB 45. What are best down and up positions. Also there is a "rope hole" in the deflector but no rope?. How was that the work? I get a lot of grass thrown out of the gap in the chasis above the rear rollers i.e beside the engine block. I dont think I have the 2 small knobs and the side spring plate set correctly.

GEAR ENGAGE LEVER/KNOB: Has anyone modified this lever on the 45 by making up a long rod so that the knob is positioned on the handle near the clutch lever (like some other brands)so it can be activated from behind the mower while operating/pushing? Or even better has anyone adapted a cable lever for the this clutch (similar to the existing drive clutch) like some other brands have? This way you would have the drive clutch activated by left hand and cut clutch by right hand (albeit you would have to keep it under pressure when cutting) unless you had a lever with a gate lock design.

Any thoughts experts?

QUOTED: Phantomguy -
"(a) the Z shaped rod (with fine slide-on spring) that actions the choke piston on the B&S Model 80202 carby. BOTH my 45 and Diplomat 430 ones snapped (they are horrible things that need just the right shape to work smoothly), and I made up one for each from hard wire, suitably burred for a spring stop, but they didn't last more than a season before snapping."

FOLLOWUP:
Deejay or anyone, any info an getting these rods and springs for the B&S engine Model 802xx with piston type choke/carby unit.

Hi P.G. Thankyou for your kind words. All the moderators and members here try and help someone with a genuine problem.

I will try and answer your questions in order:

(1) Re: subscription; send Bruce a PM (just click on his name and scroll down) and ask him of alternate methods of payment.

(2) Re: the height adjuster handle for the Model 45 was available as a spare part, if one is still available (as the Model 45 is no longer manufactured by Rover)it may prove hard to get; for the Diplomat....almost impossible, as they were discontinued years ago.

(3) Re: the teasing rake; not easy to make one unless you had an engineering drawing or physically had one to hand to copy; the spring steel tynes would be hard to make at home.
No one I know has made one, they have bought one.

(4) Re: The 10 blade cylinder reel. You would have to discuss that issue with the owner of that particular business. I have not heard of any other manufacturer of cylinder reels in Australia. Rover used to, until they went out of business.

(5) Re: Click HERE for the thread on cylinder reels and knife-blade sharpening and maintenance.

(6) Re: grass deflector; this is a simple piece of curved metal, that clips to the top of the cast iron bottom blade holder on it's bottom edge...and attaches to the front chassis rail with 2 spring steel straps, and secured by a nut and bolt assembly. The bolt has a hand knob moulded to it. It's operation is also simple....just undo the 2 black knobs slightly and slide the deflector forward or back to direct the grass into the grass-box as desired.

(7) Re: The cutter clutch engage lever; this is positioned where it is as a safety precaution. The idea is to disengage the cylinder reel as you empty and replace the grass-box to prevent (a) the grass-box attachment hooks fouling the spinning cylinder reel....dangerous or (b) getting ones fingers caught ......need I say more?

(8) Re: Briggs and Stratton parts for your carby/govenor...Bruce or grumpy may be able to help you, as I have a Honda on my machine, thank God!!

In closing, the Scott Bonnar Model 45 is an Australian made, very sturdy, self-propelled, easily maintained, "no frills" little work horse, that will give a brilliant finish and hours of mowing pleasure as only a cylinder mower can, in absolutely stock-standard condition

If you want a machine with electric key starting, cassette 10 blade reel technology, scarifier attachment, teasing rake, dual drive control and rear roller seat to sit on.....then the ATCO Royale is the machine for you.

I was thinking the same thing short term. The mower was working fine the way it was and considering the designed slippage with the cork lined clutch and drive to the rear roller, I think that the crank key in that damaged slot would be much stronger. Although not ideal, I think that I'll be reassembling with this engine until something at the right price comes along.

stu45, I have not recognized your description of your carburetor. Could you post pictures of it please, including the choke operating linkage?

Hi there Grumpy, are you able to advise on sourcing the choke lever and spring for the B&S Model 802xx engines which I was seeking in my posts 16925 and 16939? And do you have any helpful info on checking/setting the LENGTH of the governor spring so that the engine runs at the right revs under different loads?

To Deejay thanks for all your reply info. Rover also out of business these days, did not know that. FYI a UK site looks like it is selling "new" looking Rover 17" with B&S engines, but maybe these are seriously well restored units with new model B&S engines??? More importantly, if you click on the See link HERE its photo gallery one pic shows the height adjuster which looks the same as my 45 broken one(and there also looks to be an underside spring which I do not have). As for Diplomat, I guess I will just have to hunt for second hand height knob.
DOES ANYONE KNOW ANY GOOD SOURCES IN QLD OR AUSTRALIA FOR 45 AND DIPLOMAT WRECKS/USED SPARES?