How to repair an Atco Qualcast Trojan 18s lawn mower

Atco Qualcast Trojan 18S lawnmower If you don't have an Atco Qualcast Trojan 18s lawn mower, then this web page may help with other mower problems.

N.B. This web page is only intended to help you work on your mower, but I don't take any responsibility for any damage or injuries which result.

Problems and solutions.

Parts and suppliers - see my Parts List page.

General:
Manual (with a help section for basic problems).
Video introducing the mower.
The Atco Liner 18S which appears to be, more-or-less, the same mower with a few fancy plastic covers and a rear roller.
Current Atco petrol rotary lawnmowers.

Cutter blade:
Change or remove it for sharpening - see here or here (4 minutes 54 seconds in)

Body:
Engine mounting points loose or cracking.

Wheels and axles:
Front wheel height adjustment slips.
Other work on the front wheels.
Rear wheel height adjustment slips.
Rear wheel height adjustment holes worn out.

Engine (160cc. Briggs & Stratton 10D902):
Parts diagrams.
Changing the oil - see here (8 minutes 22 seconds in). It uses 600cc of SAE 5W-30 (see my Parts List for further details).
Changing the spark plug - see here (20 seconds in)
Spark plug gap - 0.030" (0.76 mm).
Cleaning the air filter - see here (2 minutes 30 seconds in, 3 minutes 27 seconds for the type used on the 18S)
Tube to carburettor loose or cracked.
Starter flywheel cover loose.
Exhaust cover broken.
Engine mounting points loose or cracking.

.

Front wheel height adjustment slips.

This shows my mower, with a high-tech bungee cord clipped on, so as to pull the front height-adjustment levers back towards the body and thus stop them slipping out of the adjustment slots.

I found this happened more often when trying to mow near bushes, etc. Presumably this is one reason for later versions of the mower having covers over the levers.

N.B. You should realise that, if the cord were to break, fall in front of the mower and thus be hit by the blade, that this would be dangerous. Therefore you should regularly check the cord.

Atco Qualcast Trojan 18S lawnmower front height adjustment fix

Other work on the front wheels.

This section shows the various parts of the front wheels, to help with any other problems.

This photo shows the wheel and adjuster removed from the body.

Atco Qualcast Trojan 18S lawnmower front wheel assembly 1
This shows the wheel assembly, ready to refit on the body.

Note that the two sides are interchangeable - only needing the adjuster aligned to the other side.

Atco Qualcast Trojan 18S lawnmower front wheel assembly 2
This shows the lawnmower body mounting points for the front wheel assembly. Atco Qualcast Trojan 18S lawnmower front wheel location

Rear wheel height adjustment slips.

This shows the my mower, with a high-tech bungee cord clipped on, so as to pull the rear height-adjustment lever back towards the body and thus stop it slipping out of the adjustment holes.

If the holes themselves have worn away, see just below here for a fix.

Atco Qualcast Trojan 18S lawnmower rear height adjustment fix

Rear wheel height adjustment failed.

The adjustment lever on mine failed to stay in place because the holes in the mower body had worn away.

What I did was to cut up a piece of angled aluminium to fit over the holes.

This I fastened in place with two M8 round-headed bolts.

Then I moved the lever back and forth so as to scrape a mark on the aluminium.

Then, with the lever moved out of the way, I drilled a new series of holes in approximately the same place as the old. You will need to size these until the pin on the lever just engages each hole.

Please note:

If the bolt heads get in the way of the lever then it will not engage properly.
The same is true if the angled piece is too deep.
The lever end will stick out further once this modification is made and may catch on the surroundings when you mow.
Atco Qualcast Trojan 18S lawnmower rear height adjustment repair

Tube to carburettor loose or cracked.

This is part number 529 at the top right of the DIY Spare Parts diagram (called a grommet and last seen at only £4.02).

I first found that the pipe, leading to the rear of this tube, had become misaligned. A relatively gentle push corrected this.

I then found that the tube had split which was corrected with a bit of copper wire taken from an old electrical cable.

Atco Qualcast Trojan 18S lawnmower Briggs and Stratton 10D902 carburettor tube

Starter flywheel cover loose.

The cover was mounted, using pop-rivets, on a base which had multiple holes.

The holes in the base had become worn.

I simply removed base and cover, drilled out the rivets, rotated the cover to the next set of holes and re-fastend it using a new set of pop-rivets.

If you don't have a pop-rivet gun, then use suitable bolts, washers and locking nuts (ensuring they don't foul the mechanism it covers.

Atco Qualcast Trojan 18S lawnmower Briggs and Stratton 10D902 starter cover

Exhaust cover broken.

There are at least two different versions of the exhaust cover. This deals with the sheet metal version.

Mine had broken off at a mounting point.

My solution was to drill a hole in the remainder, bolt on an extension piece and then use the original bolt to fasten that to the engine.

Atco Qualcast Trojan 18S lawnmower Briggs and Stratton 10D902 carburettor exhaust cover

Repairing the engine mounts.

This shows one of the mounts on mine, with a rather unfortunate crack developing.

You can see that, not unsurprisingly, the engine mount nut is rather the worse for wear.

Atco Qualcast Trojan 18S lawnmower cracked engine mount
This shows the mower body, stripped of blade and wheels, cleaned off and treated with Hammerite Kurust.

You don't need to go quite this far to repair the engine mounts but it's worth sorting out any other problems at the same time.

Atco Qualcast Trojan 18S lawnmower body repair
This shows the author, using a subtle technique to remove the old, rusty, engine mounting nuts.

You should at least wear safety glasses if doing this.

Atco Qualcast Trojan 18S lawnmower nut removal
Once the engine is removed, you'll need to cut some strips of aluminium angle to the shape shown here as, basically, large, shaped washers.

They will need to:

fit well over either side of any developing crack in the mower body,
curved so as to avoid the rim of the engine hole in the mower body,
be shaped so as to not impede the flow of grass within the mower.
not be so large that the belt cover cannot be refitted.
The extra, countersunk, holes shown here are only left over from the pieces' previous use.

Please note that this shows them held in place with M8 bolts going up and that I changed this when I realised that, if they ever worked loose, the bolts would fall down onto the blade and cause bad things to happen. I thus refitted them the other way up (see below), using lock nuts and suitable washers.

Atco Qualcast Trojan 18S lawnmower replacement engine mounts
This shows one of the engine mounts, from above. This being one that is easy to reach. Atco Qualcast Trojan 18S lawnmower engine mounts
This shows (blurrily - sorry) another engine mount, where it is positioned below the fuel tank.

You will need to loosen the carburettor, which is simple, to allow the bolt to be inserted and tightened.

Atco Qualcast Trojan 18S lawnmower engine mounts
This shows the lock nut and washer, for one mounting point, fitted below.

Note that a washer, as large as possible, is needed to prevent the aluminium piece from being distorted when tightening the nut.

Atco Qualcast Trojan 18S lawnmower engine mounts
This shows the belt, belt cover and rear axle refitted.

Note that I had to cut grooves in the cover to fit over the new pieces.

Atco Qualcast Trojan 18S lawnmower body replacement engine mounts

Please let me know if the above helped, or if you found any mistakes or better solutions (see below).

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This page last updated 16th. August 2020.
Images and text © Copyright Jim Batten, 2019-2020.

Send corrections, comments, enquiries, etc. to Jim Batten