OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar Model 45 - Buyers' Guide

Hi there - I'm new to these Forums.
I am planning to buy my first powered reel mower, I have been pushing around a manual reel for the best part of ten years now and have decided its time to upgrade (I'm getting tired of pushing).

I'm looking to buy a second hand Scott Bonnar model 45 and was hoping someone has some pointers of what to look for when buying second hand (worn parts, cracks, bent shafts, leaks etc. that sort of thing). Maybe even a test that I can do?

I'm planning on having a look at this mower on the weekend; ($550 - is there anything from these pics you can tell me?








Cheers

Hi OCDirt,

Welcome from me to the ODK Forums.
You've certainly come to the right place for advice on Model 45s.
ODK has the foremost expert on Model 45s with Deejay, the site's Global Moderator.
I'm pretty sure he will respond to this post tomorrow.

In the meantime, my observation from the photos is that this looks like a sound machine.
Most importantly, this machine appears to have a newly sharpened reel and bottom blade.
The reel appears 'straight' (no bent blades).

It has a non-original fabricated grass catcher with good serviceable life.
The engine is a replacement one (I think).

If you intend buying a powered reel mower then the Model 45 is a safe choice.
It was/is Australia's best domestic reel mower and its design has passed the test of time.

I do not see any alarm bells in the photos you have given us.
More information will follow from the expert(s).

-----------------------------
JACK

Hi OCDirt, and a warm welcome to the forum. It is nice that you have asked for some advice before purchase, and to have you aboard. We all like to learn new things and tinker here.

My thanks to CyberJack for his observations and I will add mine to them....
This machine is a 'Series 2' Model 45 with the twin rail engine deck, (which are prone to fatigue cracking under the engine mounting points) but that is a prob easily fixed.
This machine appears seller refurbished and the Briggs and Stratton has been replaced, in my opinion by a later model, it would be handy to have the complete string of numbers (Model, Type and Code) that are stamped into the metal air cowling of the Briggs for which we can get the date of its manufacture.

I would also like to take a peek into the chain case on the left hand side of the machine (looking from the rear) to check the serviceability of the chains and sprockets, as to replace the worn ones would prove expensive.

All in all, it appears to be a nice tidy refurbished machine...the fatigue issue would have been addressed before repainting, if indeed it had one, and the cylinder reel has a lot of 'meat' left on the blades for regrinding in the future.
Once again, OCDirt, to OutdoorKing.

Hi OCDirt,

From your pictures, it looks to me like it's had some repair work done to the front rail around the engine mounts. I would have a close look at that to make sure that it's been done right. I agree with Jack and Darryl that the engine doesn't look original. For some reason the air cleaner cover and fuel tank cap look to me to be older than the cowling. If a newer cowling has been swapped onto an older engine, that will make dating the engine much harder. I'm really only guessing though. The main considerations will be the condition of the chains and sprockets, as Darryl has mentioned, and how the rest of the machine runs and presents overall.

Thanks, Michael

I agree with rolla 16v that there are some suspicious marks on the front rail near the inboard engine mounting point. You should look closely at the underside of the rail to see if it has been broken, then welded up to repair it. If that has happened the frame alignment could be in doubt. The engine-side clutch half has set screws rather than a captive cotter, which may mean that it has been replaced. Failure of the original captive cotter clutch half seems to be a common cause of cracking or fracturing the front rail, so it may be that the machine's history is starting to unfold before our eyes. Coupled with the replacement engine and catcher, and whatever doubts there are about the possible alignment problems in what may be a broken-and-repaired frame, this does not strike me as a very original or high-quality SB45.

At $550, if the chains and sprockets turn out to be new, and the engine was bought new as well, adding in the approximately $200 the aftermarket catcher would have cost, the price is in line with the cost of materials to carry out the refurbishment. However it is very important that the frame alignment is correct after the welding repair that seems to have been carried out. The reel looks to have a reasonable amount of life left in it, though it seems to have had at least one heavy resharpening operation, and I can't see the bedknife to see what condition it is in.

Hi grumpy and ODK members,
In my opinion, it is very hard to tell the condition of a machine, especially frame alignment issues from photos. I believe that a thorough inspection of the machine, in person, before purchase should be carried out, where possible...if not, it could be a case of caveat emptor.

If the front rail was cracked and professionally repaired, there should be no alignment issues, and the bottom blade would have been ground at the same time as the reel, and if found unserviceable, has been replaced, I would imagine, as they have replaced other components.

This machine may have had a hard life, but one thing is assured, they are a robust design, and if repaired and correctly maintained, will last a lifetime.

I agree, Deejay. The trick is to verify that the work has been expertly done, before buying the machine. For me that would involve taking a good look at the suspect rail, especially from underneath, and talking to the seller about how the repair was made. A workshop would or should have set the frame up on a flat surface and checked it repeatedly for alignment while welding it in very small increments.

Well I definitely came to the right place to ask for advice - thanks to all respondents, I will heed your advice.
I should now have enough knowledge and confidence to ask the right questions and examine more closely.
I already feel quite weary about this sale, since it has so many non-original replacement parts. Perhaps a lower price will need to be negotiated, provided rail alignment repair and drive chains/sprockets are in good condition..

When checking drive chain for serviceability; am I checking for stretching (slop on sprocket) and tension?.
Sprockets serviceability; checking amount of teeth material? ie. not sharp/pointed or wave shaped.

Thanks again for your knowledge, much appreciated.

Most times, the chain wears, goes out of pitch, and ruins the sprockets. If you pay attention to the chain condition you may be able to avoid wearing out the sprockets. Also, never put worn chain on new sprockets, since that will wear them out quite quickly.

The first question is whether the sprockets are worn. If they are, you will need to replace both chain and sprockets. If the sprockets are not worn, before putting the mower into regular use you still need to remove the chains and check them for wear. If they are showing signs of wear but the sprockets are still good, replace the chains immediately before they ruin the sprockets.

To inspect a chain for wear, turn it on its side and note how much the center of the span of chain sags below the two ends. Sag is caused by wear on the pins and side plates. Wear on pins and side plates increases the chain's pitch. Increased chain pitch ruins sprockets.

Another quick question - Is there much of a difference between a Rover and Scott Bonnar Model 45s in build quality and parts used? Is one better than the other?

Hi again OCDirt,
I think it is a matter of taste between the Series 2 Scotty's with the twin rail engine deck and the Rover 45; all parts are interchangeable...but in my opinion the Scotty is more desirable...some say the build quality is better.

Some people say The Series 1, with its solid engine deck is more desirable...and therefore more collectible....but, being first introduced in 1968...and replaced by the Series 2 in 1976....they are getting long in the tooth now and most probably employing replacement parts to keep them at their best.