OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Reel-Type Mowers Scott Bonnar 45 Chain length and roll pin removal.

Hi All,

Long time reader, first time posting. I have a 30+ year old Scott Bonnar 45 14" that my granddad bought new and passed it on to me. I have had it for 10 years now and is (finally) getting tired so I've started to rebuild it while still using it. I have purchased a lot of parts (sprockets, bearings etc) from the OutdoorKing website and I have some questions. Apologies for so many...

1. The cutter drive chain. The new 40 link chain appears to be too loose even when at max adjustment and with new sprockets. Is this normal or is 40 links too many.? I'm thinking of removing 2 links to reduce the slack. Is there a standard movement distance like on car engine V belts?

2. The roll pin on the sleeve clutch is hard (impossible) to remove. How is this best removed? I would have preferred to purchase a new sleeve but this appears it's not available for sale or is it?

3. Clutch inner cone. The surface where the cork pad touches is very shiny. I've had a lot of clutch slip over the years and I believe this has "polished" the surface. Should I roughen up the surface manually. Eg, with sand paper or just leave it?

4. Since putting a new cork pad on the outer cone. The inner cone does not protrude as much as it did with the old clutch pad. It's around 3 to 5mm further in. This is even with a new clutch spring. Is there an exact location to bond the cork pad because it's not the same width as the outer cone or doesn't it matter.? I have not started the mower yet to see if the clutch works as it should.

5. Lubricating the chain and sprockets. Is engine oil the best to use?

I have more questions, but will post them another time.

Thanks and hope everyone has a good New Years.

Hi Corduroy, and a warm welcome to the forum.
It's always nice to welcome another Scott Bonnar owner, as we all like to learn new things and tinker here.
In order to give you the correct advice I need to know exactly what model Scotty 45 yours is, as there are 2...the Series 1 with the solid engine deck and the Series 2 with the split rail deck....There is a different method of chain adjustment between the 2 models.

Also what engine is installed...the Kirby-Lauson or the Briggs and Stratton.
If it is the Briggs, can you please post the complete Model, Type and Code that is stamped into the metal air-cowling; from that we can give you the year of manufacture of the engine which will give us a rough idea of the age of the machine.

Can you please post some photos of your machine from different angles including the cylinder reel and bottom blade, the chain case including the chain and new sprockets. Instructions for uploading pics can be found Click HERE

I have never counted the links in my Model 45 chain as mine is still the original, so I can't help you there...However, after the cylinder reel and bottom blade adjustment has been carried out successfully, the primary chain is then adjusted so that roughly 1/2" play in the chain is observed in the middle of the chain.

I don't know what you mean by the roll pin on the sleeve clutch? Can you please post a photo...
The Model 45 has 2 clutches; the cutter clutch (engine clutch) and the drive clutch (drum clutch) I have not heard of a "sleeve" clutch.

The best way to remove the shininess of the clutch cone would be to carefully sand blast the area with fine grit blasting medium.

The position of the clutch cone will be different once you have re-lined the outer clutch half with cork, the cork should be placed near to the inner edge of the hole in the outer clutch half and glued in position using the cone to hold in the correct alignment whilst drying.
Here's a pic:


I use a good quality grease on my chains....see our video the we made...Click HERE

Hoping this has been of help, once again Corduroy, to OutdoorKing.

Hi Deejay,

Thanks for the reply. You do have a wealth of knowledge.

I have a split rail deck, so this would be a Series 2.
The mower number reads 00873 and model 450511. I believe these numbers don't state the year it was made, just the model and order it was made, being 873.

The engine is a Briggs. However, I bought a new one around 6 years ago. Model 093312, Type 0155 E1, Code 060215YA.

The below picture is the day I replaced the original engine.



The sleeve clutch wording was taken from this website...and probably my poor explanation. Its a sleeve that goes inside the bearing for the engine clutch. Sleeve Clutch Link Its Number 29.

If you don't know of an easy way to remove the roll pin, do you of any places/websites that sell this sleeve?

Anyway, I ended up using my original bearing, roll pin and sleeve in the new sprocket. The bearing seemed to be ok.

I got the cork position all sorted. Below is a picture showing the gluing process.....not that it would help in showing.



Regarding the chain lengths, as yours is original, it would be good to know how many links it is suppose to have. But don't go to any trouble, I have got mine all sorted. I had to add a half link to the Drive chain so both the Drive Chain and Roller Chain could be adjusted correctly. Its hard to explain, but without this half link the Roller chain would be too loose.

Below picture is of the old, assume its the original gearing.



Below picture is of the new gearing. Not adjusted and no lube.


Are there any recommended torque settings on the nuts and/or bolts for all the sprockets? As the nut on the reel/cylinder sprocket can lock the sprocket if its over tightened. I found this out!!

Also, what is a good grease to use, could you mention a brand name? Would wheel bearing grease be ok to use?

The basic manual I have says to use engine oil. But that's only going to come off caused by the centrifugal force. I only used oil to install the bearings and sprockets.

Thanks again for your help. I can post more pictures if needed. I have about 50 of them showing the steps I did on replacing all the gearing.

I am what you call a home handy man, but this is the first attempt on replacing the gearing. I'm sure by the photos someone will pick up a mistake or something missing

Corduroy,

If you place the chain adjuster on the outside (pushing chain inwards) of the chain your tension issues for the cylinder will be corrected. With the old Thoroughbred models the tensioner was on the outside of the chain.

Hi Corduroy, and thanks for posting that information for us.
Something seems wrong with the engine code....Its telling me that engine was manufactured on the 15th February, 1960... The Model 45 wasn't introduced until 1968.
Could you please check the numbers again?

Regarding the Drum clutch sleeve and pin, I will send you a PM with some details...just check for a flashing envelope in the toolbar above next to "My Stuff"
The reason I have seen one is that I haven't had to recondition my rear roller assembly as yet...(touch wood!)

I'm glad you got the chain issues sorted, the next time I have the primary chain off, I will count the links and post the results here.

The grease I am using on my chains is Caltex 'Aqua Tec' high water resistant graphite grease. I has done the job admirably.

I have not seen a torque reference chart for the Scotty, but I just tighten everything up firmly, but not over-tight.
It's a good idea to check all nuts and bolts on a regular basis anyway, as a bolt, washer or nut falling out on your lawn can have a dreadful consequence for the cylinder reel and bedknife.
Congrats on replacing all the gearing, I hope your machine performs well for you...
That engine code has me tossed though...

I love these little 14" model 45's Corduroy, it'll continue to be a great mower with all the work you're doing

Darryl, I believe the Briggs numbers are from the new engine, which at 15th Feb 2006, is consistent with when Corduroy said he replaced it.

Thanks Rolla, that explains it mate....I thought the numbers ran back to front...

Thanks Bruce, that explains why the old stretched chain kept on sliding off.

Thanks Rolla for comments. They are great mowers, well designed and is a good size for my lawn. It's the main reason why I haven't upgraded in size.

Thanks again Deejay for your help!

After finally setting/adjusting it today. I started it up and what a amazing difference. So much more torque and acceleration. It use to struggle cutting when going up a hill. The other positive is that I dont need to over stress the engine to make it cut and move. I can see myself cutting my lawn twice a week now just so I can use it...