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Collection, Preservation and Display of Old Lawn Mowers

Ransomes Marquis - Villiers Sloper Bogging Down Under load

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My first post here so be gentle.

I've just tried to reinvigorate my Ransomes Marquis which I hadn't been using for a few years. It runs with a Sloper Engine fitted with a Villiers B10 carb.

Initially it had no spark, so took the coil\points off to clean up and check.

Now back together the engine starts first pull and will accellerate up, whilst stationary.

However under load it loses power and would  cut out if it wasn't handled correctly.

The Carb has been cleaned in Petrol overnight and blasted with Carb cleaner - although I appreciate that a carb can never be cleaned too much, as there could still be dirt at play here.

My suspicions are that it is either the points timing or the carb still not set up correctly.

How do you effectively re time when there are no markings to align to? without having to remove the flywheel\pull cord every time

What should I be checking first, then what next??

Thanks in advance

Rob

Forums

wristpin Sun, 19/04/2015

You say   "However under load it loses power and would  cut out if it wasn't handled correctly."

Remember that it is an un governed engine and the operator has to compensate for changes in load with small throttle inputs.

Unless you've made a complete mess of the points there's no reason to think that the timing will have altered during it's period of disuse so here's a list of other possibilities.

Chain too tight . Blades blunt or out of set. Cylinder bearings stiff. Roller bearings stiff. Centrifugal clutch shoes seized on their pivots - this might bog down the mower but not the engine. Too much grass!

Check out that lot and if there's no joy there you may need to have a look at the timing plus  valve condition and clearances.

 

 

RobBrown Sat, 25/04/2015

HI

The Points had to be adjusted to get the spark back. In the process of doing this the points were removed as I originally thought the coil needed replacing, so everything was removed.

Cylinder sharpened and moving freely. Roller OK too. Clutch fine. 

The grass was quite thick so had to work hard, but this was a little more bogging down than normal engine governance.

RobBrown Sat, 25/04/2015

Yes - Bogging down under load.

 

My question is how do I make sure the timing is correct without any marks on the engine casing.

wristpin Sat, 25/04/2015

Remove the flywheel to expose the ignition stator.

With the heal of the points on the peak of the cam set the gap to .018" (eighteen thou)

Remove the cylinder head to expose the piston.

Turn the engine to the top of the compression stroke (both valves closed.

Turn the engine back (anti-clockwise) till the piston drops by .125" (3.17mm)

Slacken the two slot head screws that retain the ignition stator plate and rotate it back and forth in its slots  - may be with a drop of lubricant - so that you can move it accurately so that the points are just starting to open with the piston in the correct position.

Everyone has their favourite method of locating "just opening". The proverbial fag paper between the points and feeling for the release point as the stator is moved, multi meter to check for a break in continuity or in my case a useful little gadget that gives an audible signal leaving hands and eyes free for the job in hand.

While you have the head off I'd suggest removing the valves, refacing and reseating them and setting the gaps to  6 thou, inlet and exhaust.

On the matter of the engine bogging down. Over the years  I have owned, serviced and bought and sold dozens of Marquises with Sloper engines and I would not expect them to perform well if asked to take off more that half to three quarters of an inch of spring grass but I'll take your word that you have a problem!

Further points issues may be avoided by fitting an "electronic module" that does away with the points and condenser and maximises the coil output. I use the Meco module sold by Central Spares and fit it to all slopers passing through my hands as a matter of course.

 

RobBrown Sun, 03/05/2015

I feel like a fraud.

I have found the issue and it is in line with your initial diagnosis.

The drive chain itself is seized, although looks OK, is as stiff as a board and is not allowing the sprockets to flow freely, hence when everything was engaged nothing moved freely and thus what appeared to be bogging down was actually the drive not functioning correctly.

I've emailed the spares mailbox on here to see whether a replacement chain is available.

 

Wristpin - Thanks for your patience.

Regards

Rob

PS. I'll update on here once resolved, for future reference

.

 

wristpin Mon, 04/05/2015

Good news , but before rush off to buy a new chain why not soak yours in some diesel for a few days, working the links back and forth at intervals.

However, if you can't salvage your existing item the chain is standard BS (British Standard) chain available by the foot from your local bearing factor although despite the BS prefix is possibly now made in Foreign parts ! By mail order a supplier such as Simply Bearings should be able to help.

From memory the  long chin is 67 links plus a connecting link, 68 in total. When purchasing new chain get a new connecting link as ,depending upon the chain manufacturer, the pin size may vary and your existing link may not fit.

Your next question is possibly going to be how to adjust the tension of the new chain. This is done by slackening the clamping "nut" that holds the traction clutch to the chassis and sliding the whole clutch assembly about to apply the correct tension to both chains. Easier to do with the aid of the Ransomes special tool which is still available at a price of £20 - 30.