OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Other Walk-Behind Rotary Mowers Scott Bonnar Spincut Rotary Mower

Good Evening ODK Members,

A friend was over dropping me off some parts and he had a few mowers in his trailer, he asked me if I was interested in anything that was in there. There was one wreck that was interesting as it had a JAP engine on it and spare parts are always good. He told me the engine was seized and it was going to be garden art if I didn’t want it, I asked the price and it was free 👍



I stashed it behind the shed until I could have a better look over it, there was a lot missing and it was definitely seized. Holidays arrived and I made space for the Spincut on the workbench. The engine was missing its fuel tank, muffler top and starter pulley but did have a carburettor.

The base was perfect and still retained its brass identification tag, Model 22



When I saw how good the base was I wondered how seized the engine was, magneto all came off without much trouble and then I separated the bottom third bearing assembly from the engine. More on the bottom bearing later. I managed to get the cylinder off finding the piston badly corroded where it aligned with the exhaust port, bad design here as when the mower is left in the elements moisture builds up in the exhaust pipe and finds its way down into the inside.

Crank was stuck so I split the cases and found rusted bearings and a frozen conrod. Bearings are no problem but I needed to free up the rod, I soaked the crank in some strong caustic degreaser for a day and then took it out and gave it a tap. It moved a bit so I tapped it back and forth for a while and kept cleaning it and applying WD40 until it was totally free. Soaked it again and cleaned it again until it was rotating smoothly.

The bore honed up ok and I found a spare piston, rings and a gasket set in my spares



Incidentally the seals on the JAP Model 80 are fitted from the inside as there is a retaining lip on the outer case, bit of a bugger when you have bearings frozen into the cases.



I managed to remove the bearings and seals and had no trouble getting them from my local bearing shop, the seals were destroyed so I took the crank and cases with me for measuring up. Bearings are 2 x 6203 for the crankshaft.



So all apart and after a lot of cleaning and some orange paint the engine is ready for reassembly 🙂

Hi Paul
A lot of folks will be reading this one.

I now realize that you now write with flair and enthusiasm.
Members love this stuff! I do too!

Awaiting the next installment.

Many thanks for saving this one.
Your knowledge saved this one.

Cheers
-----------------------
Jack

Good Afternoon ODK Members,

A bit more on the Spincut, cleaned up the engine cases, barrel and cylinder head. Then they were given a good coat of orange paint







With all the cases etc done I reassembled the engine and turned my attention to the lower support bearing. The bearing wasn’t seized but was very noisy so I decided to replace it. Now this bearing is not fed lubricant by the engine fuel mix but is totally seperate, it is to be lubricated by removing an access screw in the blade boss. The screw is number 8 in the picture





After separating the bearing hub I removed the old bearing and fitted a new one, bearing is a 6205






When fitting the bearing you must remove one of the seals, the one facing the blade plate so the bearing can be lubricated as previously mentioned. I left the grease in mine as the mower will only be run occasionally, I did debate whether to just leave it totally sealed but in the end removed one seal so a drop or two of oil can be applied later. I left the back seal or engine side in place so moisture or water would not enter.

All back together


Here you can clearly see the oil hole, I would probably remove one of the blade plate retainer bolts to give better access to the bearing



I would say that this bearing was probably forgotten about by future owners and would have run dry if not serviced at a Scott Bonnar dealer.

Good evening ODK Members,

A bit more progress on the Spincut, I was getting the base ready to repaint and used some paint stripper to remove the paint. To my delight it only removed the newer blue paint that someone had used to refresh the mower in the last. It revealed quite a bit of the original orange paint so I decided to try the engine cowl as well












I was missing the fuel tank and muffler top, I found that I had both. The tank was on a stationary engine and the muffler top on a scrap engine, very happy that the tank was orange.