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Collection, Preservation and Display of Old Lawn Mowers

Setting up the Governor spring mechanism on Classic 35s

Hello i have a Classic 35s 2000 model and i have put a new carburettor on and a new governor spring ,now im new to all this so the way i think the set up works is the spring should have no tension on it so the butterfly rests at idle then when you move the throttle handle towards the max position the spring is tensioned and the butterfly is opened on carb is this correct or not and how do you now if the governor arm is set in right position on the shaft .Hope this makes sense and if anyone can help would be  very much appreciated


wristpin Wed, 02/06/2021

You are on the right track. The basic operation of the governor is that the internal mechanism of a running engine always tries to close the throttle and this is opposed by the handlebar mounted control via the throttle cable and governor spring. The result being the governed speed.

The relationship between the shaft from the internal governor and the external arm is “ fixed” , either by construction or on initial assembly. Despite what may be seen on YouTube it is not a speed adjustment.

If you post an image of the bottom end of the governor arm where it joins the shaft  it will ensure that any advice in the setup procedure is correct for your application .

wristpin Wed, 02/06/2021

Looks like that governor arm is located on two flats so can only go on one way. I’ve got a similar engine buried in the shed and if I get a chance will have a look tomorrow. The spring looks correct. Do you have a specific issue with the machine? 

steve90 Wed, 02/06/2021

The governor shaft has flats on end only for spanner and when you remove arm the shaft turns anti-clockwise and the returns to orignal position. i just want to check it is set right as i believe and i may be wrong but it should increase engine speed to maintain blade speeds

wristpin Thu, 03/06/2021

Slacken the clamp screw enough to allow the shaft to turn, move the governor arm full to the right ( throttle fully open) hold it there and rotate the governor shaft clockwise and tighten the clamp. 

steve90 Thu, 03/06/2021

Hello again need you help on rear roller need new bearings but don't know what part no is can you help please

wristpin Fri, 04/06/2021

I guess that you are referring to the white item secured with three pop rivets. F016A57674 but it's now the later part useing the bevel gear from the split roller machines. Looks different but does the same job. Rivets F016A58178 (x3) They require a heavier duty tool than the average DIY offering. 

steve90 Fri, 04/06/2021

Thank you i didnt know that was a gear i just looked at end and seen a circlip(same both ends)and have not taken off yet but there is play in the roller and wanted to replace whatever needs doing