OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Reel-Type Mowers 17inch Scott Bonnar Restoration

hey guys, been reading this forum for a little while now and finally decided to dive in and attempt to repair/restore a scott bonnar.

I picked up this bad boy just today, and I'm excited to get it back to its glory days. This is my second bonnar as my first was previously restored by someone else, and is now used to cut my lawn. My new one is a 17inch 45, its not in running order at the moment and i need a little help getting it going. First the Photos







Ok so i have changed the spark plug (Champion CJ8) put new oil, wasn't sure on how much i put just over 400ml in, and put some new fuel in 98ron. But I'm still unable to get the motor to run, I need to change the filter but the local mower place had no parts so i need to order one. Any hints or tips on how i can get this engine going would be great.

The first point of call would be to make sure the magneto is actually generating a spark, remove the spark plug, and install it on the lead and rest the metal part of the plug against the engine. Wit hthe throttle in the run position briskly pull the starter rope a few times to see if there is a steady stream of sparks at the end of the spark plug.

If there is spark you would need to look at the fuel system a little more, this can be confirmed by putting a teaspoon of fuel down the sparkplug hole, reinstalling the spark plug and trying to start it again.

In those little Briggs engines you fill it until the oil level is level to the filler hole with the engine sitting flat.

Please turf that filter and put the empty casing back on for the sake of a couple of tests, that foam is ready to break up and it will end up all through the system. a couple of very short runs wont hurt it. The filters are still available relatively cheap, they are not commonly used anymore so I am not surprised that your local shop doesn't keep them in inventory.

thanks for the tips joe. ill get rid of the filter now, I was looking on the outdoor king online shop is this the part? filter

i did try the spark plug out of the casing like you said and i was getting a nice even spark while i pulled the cord, i then added a teaspoon of fuel like you suggested and it after a couple pulls the engine turned over and ran for a few seconds then cut out. So it seems that there is an issue with the fuel system.

what would you recommend i try next?

thanks again for the help champ

Hello Solman

The correct filet for your machine is p/n 27987.
It is the older style for the Model 80202 0879-01
It is located HERE.

Hope this helps.
--------------------------
Jack

Thanks jack nearly bought the wrong one.

Hi all,

Your Rover Scott Bonnar was probably manufactured in the early to mid 1982 era at the Thebarton Factory. The engine was built on the 4th of November 1981 and as such would've been fitted to a newly made chassis around 5 to 6 months after that build date. A Scott Bonnar chassis can not be dated precisely as they never had a numbering system that incorporated any dates within it, thus only the Briggs equipped mowers if original can be approximately dated. The other mowers only us more experienced Bonnar nuts can approximate their period.

One thing that's different about yours is that it has a "Rudolf Red Nose" knob instead of a black unit fitted to the primary clutch lever, just wondering if this has been changed by a previous tenant.

I notice that your machine has the sticker that has only a serial number on it. This was used prior to the new green Rover Scott Bonnar Aluminum silver and green ID tag that was the next step in the evolution of the model 45.

Cheers,
BB

PS. It's a good boy and not a bad boy.

600ml is the norm , but as joe said fill it until you can see it full at the dip/plug hole i have had some luck just draining the tank and a fill to top with fresh and allow to sit a couple of days soaks it out sometimes then get it to fire and it sucks the bad out and in with the good ..

or it can get to be some fun cleaning jets n stuff out , at worst if you cant find it a different air cleaner will fit on there just be sure it doesnt foul any linkages

Thanks for all the tips guys.

I found this video on how to restore the carburetor

Watch "Briggs Carb repair step by step" on YouTube


Can anyone recommend a carburetor cleaner, and gasket sealer?

Carburettyor cleaner I live and swear by CRC clean-r-carb it is by far the best I have used, shouldnt need any sealer as such just new gaskets....

Before going tothat extreme though, it would be worth to make sure the choke is closing, thats the litle tab on the back of the carby under the air filter, it should be able to pull right out and blockthe throat of the carb. If thats not working you will have a bad time trying to start it.

Hi guys so today I rebuilt the carburetor,with a kit that Bruce helped me pick out. Heres a picture



A problem I have encountered once I rebuilt it, is that the rip cord was occasionally spinning freely,and now it always spin freely on the shaft. Here's a picture, any suggestions on how to fix this?



After all this I still can't get it to start, fustrating day. Also I started a small fire which burnt the insulation on the kill wire hence the electrical tape on it

it could be that the starter clutch is dirty inside , full of old dust and engine crud . the little tin plate should pry off and you will see i think 6 steel balls inside . on that angle they will probably fall out so take care they dont zap under a workbench or some golf clubs .

give the housing a good clean out of all crud and the balls too . make sure all clean and DRY , as in no lube at all just really clean and grease free . just a small amount of light engine oil on the shaft as it lubes the INSIDE of clutch on shaft as will with have an ear piercing squeel most times if its dry . or a replacement is i think $20 + maybe in store here .
give it a try , works almost always for me ......... if it is the problem .

, Dave

Thanks Dave. I did what you said and gave it a good clean out, and i think it's done the trick. I didn't end up removing the cap on it, it seemed to free up after I cleaned it up. This a picture of it cleaned



I also decided to clean and paint up the cowling


I had some hight temp red paint left over from another job and thought I would give it a go to see what it looks like.

looking good there solman , nice red too ... but they do really need a clean inside too , its just a pop it off with a screwdriver job and you will be surprised how much rubbish in there over the years . dust and old oil hardens , nothing worse than sticky balls !!!

while its at this stage is a good time too do it , drain the oil from engine if you didnt already change it . lay it on its side and pop it off , its only the 2 tiny screws and the mesh cover that holds it on . or just a little light sewing machine oil in the tiny hole ..... lubes the shaft and helps prevent the squeal i mentioned before .
looking good so far though

Hi Solman and vcccomm,

Yes that's pretty good advice to clean out the ball lock chamber as all you have to do is slide a knife between the metal plate and the housing and then clean out the chamber of the gummy lube that's creating the problems. Once cleaned out just a little light oil as vccomm suggested and lean the engine back to insert the balls so they don't end up everywhere else apart from where they should go. Also while I remember the square ended shaft end that fits into the recoil stater assembly should be slid off it's shaft and internally cleaned out and new oil placed onto the exposed shaft, then just slide the shaft end cap back on and insert those balls, finally slide the sealing plate back on to where it belongs and you should have a super efficient starter functioning as it should without any of that squealing noise.

Cheers,
BB

oooooh , sorry BB i meant on the shaft ONLY , as if any oil in there and the balls will attract dust and stick soon after . so when the square part if off , just a light lube on the long round shaft a drop in the felt up top and good to go . a tad confusing but when its in front of you its easier .
still im not great at explaining

Hi vc,

I must admit I've always used the slightest of light machine oil on the balls prior to installation and have never had an issue. I guess what I call slight is merely a oily rags worth with the balls rolled around inside the rag which would only put a film on them and not have them wet, nothing more.

Cheers,
BB

i understood what you meant BB no worries , just better often on a 45 that way so as i'm not a reel mower guy your correct mate , just on all the older ones i had it was always full of dust and rubbish so dry suits better for rotarys is my feeling just pounds the powder to finer powder and sort of lubes its own self but still needs cleaning one every 40 years or so hehehe .

I like your caution on not to drop the balls vccomm, I see you have spent a bit of time on your hand's and knees.I have ball bearing's all over the floor in my shed I just can't find them.

Thanks guys I ended up pulling the starter clutch apart as recommended and gave it a good clean


After messing about with the carburetor again I managed to get the motor to start and run! Happy days.

I pulled the motor off the chassis to clean it up more, and notice that the clutch bolts didn't seem right. Heres a picture



Are these the correct bolts to secure the engine shaft to the clutch?

Hi Solman,

No they are not correct as they use either allen keyed grub screws or short square headed set screws, but honestly they are fine if you have nothing else but I would shorten them as they are a tad long and thus would add a bit of unbalanced weight to the clutch body.

Cheers
BB