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Collection, Preservation and Display of Old Lawn Mowers

Fuel evaporation, uneven lopsided cuts

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Dear mower men and women,

Two questions about my atco balmoral 17S.

1. Is fuel evaporation normal? The fuel cap has a cardboard insert with two holes. Typically all the petrol will have evaporated within two weeks.

2. How to trouble shoot uneven cutting? My mower seems to cut shorter on the right hand side of the cylinder and less or possibly not at all on the left. It seems to be worse when driven and less bad if I push the mower.

Many thanks

Forums

hortimech Tue, 29/08/2017

1) Yes, it does seem to evaporate quickly nowadays, but it leaves a residue behind.

2) Start by checking the rear roller bearings, is there any movement in them ? does the rear roller move about. If there doesn't seem to be anything wrong, check the front roller assembly, is anything twisted etc. You can check if there is a difference between the height of cut on either side of the machine by placing a straight edge across the front and rear rollers at one side. measure the gap between the top of the bottom blade and the underside of the straight edge, move the straight edge to the other side and repeat, the measurements should be the same. If there is a difference, you need to find out why.

 

wristpin Tue, 29/08/2017

Fuel will evaporate but "all in two weeks" seems a bit excessive. How much is all ?  A very warm garden shed  or leaking needle valve in the carburettor will all contribute to fuel loss while standing. If the machine has a fuel tap make sure that you turn it of  when putting the machine away.

Cutting. Two factors, quality of cut  - is the grass being cleanly sheared ? and level of cut - is the machine cutting parallel with the ground? Quality is governed by the sharpness of the rotating blades and the fixed bottom blade and then the accuracy of the interface between them.  Sharp and properly set up blades will slice a strip of copy paper at all points along the width of the mower. An adjusting screw at each end of the cutter unit will help with this setting but if the blades are rusty, damaged of blunt more drastic action will be needed.

Level of cut is governed by the relationship between the rear and front rollers and the bottom blade . Tip the machine back and place a straight edge so that it touches the rear an front rollers and  check that it has an equal relationship with the bottom blade at each end.  There is provision to adjust the level of the front roller and, if memory serves me right, some adjustment for the cutter unit in the chassis.  Wooden front roller can wear both in their diameter and at their interface with the steel spindle.

Alexh Tue, 29/08/2017

Cheers both. No tap on the fuel line unfortunately and the shed gets very hot. I'm now filling the tank very little and aiming to run it dry. I suppose since I noticed I've been leaving less in so then more likely to be evaporated!

The cylinder is recently reground, should mentioned the problem was present before that. Making good contact along the bed knife and cutting paper nicely. 

Front roller looks well set to me. I'll have to look at the rear roller and measure height of the cylinder from the rollers.

Simon Thu, 31/08/2017

Just a query, my colt seems to cut nicely but should the cylinder blades kiss the bottom blade slightly or have a very slight gap?

wristpin Thu, 31/08/2017

Set it up to cut paper cleanly all along and then back each adjusting screw off by an eighth of a turn to obtain a decent cut without undue wear. If you have to set it hard to obtain the paper cut it probably needs sharpening.