OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Hey everyone, Few questions from a newbie :)

Hey there all, New to the forums and new to the delicate world of Scott Bonnar . I was lucky enough to pick up a machine for $90 but have a couple of questions. Firstly this thing hammers, when i engaged the clutch with the lever i have to just about run behind it to keep up. Strange thing this is happening with the throttle right down and i have no real idea how to slow it!

Also ive been having a look at as many pictures as i can and have found that the mower i have dosnt have the clutch lever or cable attached to the handle bars, i was wondering if that could be an answer to my problem?

Thanks for your help in advance, I've posted some pictures Hoping this helps...

Hi RideTo Live, and a warm welcome to the the forum. Its great to have another Scott Bonnar owner on board. We all like to learn new things and tinker here.

Just a heads up, as a newbie, please note that advertising is inappropriate on OutdoorKing, and is against the forum rules of conduct. I have removed the reference to the Ballarat business to which you were referring. I hope you understand this decision. Please read the FAQ located on the top toolbar, for further information.

From my observations, I have noted the following;
(1) What you have there is a genuine Scott Bonnar Model 45, 17" machine and from the pics, is a fairly late model.

(2) The original Scott Bonnar ID plate, normally affixed to the rear rail of the engine deck has been removed...you will notice the 2 holes where the plate was originally riveted. This plate carried the model number and the mower number....This removal is unusual....

(3) The handle bars are not from this model of machine; they are from a Scott Bonnar Lawn King, a very early model of SB 45, painted in a hammertone cobalt blue colour.

(4) The inner cutter clutch housing is suffering from "Tenants Improvements" (the previous owner) and has been radically modified; I think a hole has been drilled through the cutter clutch housing and perhaps right through the engine shaft, and a crazy nut and bolt set-up fitted It should contain a captive cotter pin.

(5) The cylinder reel looks in great nick....maybe never re-ground....but it will need re-sharpening, as will the bottom blade. At that time you will need to remove the cylinder reel and sole plate complete with the bottom blade (bed-knife)and take both to the engineer who will do the grind for you....See this thread....Click HERE

(6) Considering the overall condition of the machine, at the time of the reel and bed-knife sharpening, you might consider replacing the reel bearings, as they are critical to achieving perfect reel to bed-knife clearance adjustment when the assembly is re-installed.

(7) You are correct, the roller clutch handle, cable and associated assembly is missing, as you guessed is causing the over-speed problem...these parts can be easily sourced and fitted...the condition of the roller clutch will have to be ascertained at the same time...but may be perfectly serviceable....hopefully.

To enable us to assist you further, can you please post the complete string of numbers stamped into the air cowling of the Briggs engine. From these numbers we can tell you the date of manufacture of the engine, and grumpy, our resident Briggs and Stratton guru, will be able to give you advice on getting the engine purring like a kitten!
Can you please also remove the chain-case cover on the left-hand side of the machine, and take some close-up pics of all the sprockets...particularly where it is not covered by the chain....from this we will be able to advise on the sprocket and chain condition.
As for the handles, this is an illustration of what they should look like on you machine...you should be able to source some in Ballarat... (If you get my drift! )

Hoping this helps, and once again, to OutdoorKing,

Thanks so much for your help so far, The id plate was replaced for some reason with a stickered version, and i wiped it to see the numbers better and must have wiped the dirt that was making the numbers visible lol so i cant see what it said at all now!

I thought so about the handle bars they threw me at first but then i when you replied it made a bit more sense, im currently chasing down another set in pretty good condition.
I'm not sure what to do with the clutch? It seems to be working fine, but if its going to cause more harm than good i guess im forced to fix it.

Here are the pictures as requested, im currently pulling the 45 apart for a good clean, re-paint and replacement of all the rusty,stripped,crossed threaded bolts and nuts that are throughout the mower!

Thanks again, Daniel

Those sprockets are fairly worn, but not as bad as many we see. Whatever you do, don't replace a chain or sprockets without replacing the mating parts: replace a set of meshing parts or keep using the old ones. If you clean your chains properly, then keep them clean and oiled, in normal suburban mowing you may get a number of years out of those sprockets and chains. Just remember, degrease and re-lubricate the chains regularly. When you can see or feel just a bit of grittiness on the inside of the chaincase cover, it is time to service the chains again. By keeping the inside of the chaincase as clean as the chains, it is easier to tell when some grit has got in. By persevering with those fairly worn ones, you can learn good maintenance habits without risking an expensive set of new parts.

I have a 2nd hand clutch handle/lever and clutch cable if required.

Hi Daniel, you might find my post; (Click HERE) may come in handy in giving you a good regime, for routine maintenance of your Scotty, and in particular the chain-case area.
Regarding the handle-bars and its cover...second hand units, in good condition, may be available...just send me a PM and I may be able to help.

Re: the sprockets, as a Model 45 owner myself, I feel replacing them at this time would be over-kill, mine are over 34 years old and have never been replaced...admittedly there is some wear...but not causing any probs at the moment....save your penny's and replace them down the track...Just keep the dirt out, and grease regularly...Yours are particularly in good nick for their age!
Keep us informed of your progress Daniel, and pics please as you go along.
Best wishes,

Jarrad thats a very interesting offer, whats the condition like and dose it come with all the parts i would need and lastly would you be willing to post it at my expense of course to Ballarat 3356?

Grumpy - Thanks for your help, I think ill keep a hold of these sprockets at least for a little while and keep them very well service as you suggest. Ive gone through the service thread and its very informative and backs up what your saying, im currently soaking all the parts in diesel at the moment and well then dry and re grease etc when it all goes back on.

DeeJay - Thanks for the link, as posted above ive checked it out and am currently following what you have said. Ive shot though a pm to you about the bars as well. Thanks again.

Please see attached pix of parts which are available.

Handle comes with the two pins and clips. One to attach cable with and the other is the pivot pin.

The clutch cable is complete, although has some damage to the rubber outer casing. It is still fully functional and could be patched up with some electrical tape or heat shrink. You can see the damage to the black casing in the first pix. The cable is still straight and not kinked.

Price $15 which includes postage. Brought these as spares for my old mower and the new one has cables, which are like new. Selling for what I paid for them.

Drop me an Email if your interested: jk_datto@hotmail.com Be away from internet until Saturday

Guys, this digression has reached the point where it belongs in Wanted rather than a mower thread.

Hi Daniel and Jarrad, grumpy is right, negotiations should be carried out preferably by PM, not in the thread, as it sends the thread 'off topic' and upsets the flow of the archive....

Daniel, as you are to strip, repaint, replace etc. you are essentially doing a renovation, could you please start a new thread then in the Repairs and Maintenance forum >Questions on Scott Bonnar Cylinder Mowers, and name your topic Scott Bonnar 45 Renovation or something like that....

Please take some progress pics as you go along....ask as many questions as you like...we are here to help and advise you...this will create a valuable and important archive for future members contemplating a renovation of their Model 45.

I shall now close this thread. If anyone wishes to add anything further, please PM a moderator.