Marquis 4A Sloper Engine Removal

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RickT
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Marquis 4A Sloper Engine Removal

Hi - I am restoring a Ransomes Marquis Mk4a 18 inch mower. I have cleaned everything and decoked head and top of cylinder. I have managed to make a gauze and felt washer for the Amal carb (felt pads are still available) - all of which were missing. Carb cleaned in ultrasonic cleaner. Originally no spark at all even with old incorrect spark plug replaced by correct NGK replacement for Champion N8 (NGK BR5ES) and new suppressor cap. After following wristpin's guidance (from other forum topics) on how to recover contact breaker performance there is now a very rare and weak spark. Possibly a coil issue but I am starting with the cheap bit by replacing the contact breakers with meco electronic ignition unit.

Before I reassemble everything and try again I want to reseat the valves (lapping paste etc). So I am trying to remove the engine from the Marquis chassis so that I can place on workbench to remove the valves following the anticipated fiddle to remove the valve springs etc.

Other topics suggest I should be hitting the flywheel towards engine/away from drive shaft whilst pulling the engine away and turning the flywheel to separate flywheel from clutch/drive shaft. I need at least 4 hands for this! However I have had no apparent success as yet, Am I just being a wimp and need to continue with confidence or does anybody have some further information or experience to offer?

Many Thanks RickT

wristpin
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The R in the NGK number

The R in the NGK number suggests that it is a resistor plug which should not be used with a suppressed plug cap. When that engine was new it probably had neither! I would use a non resistor plug . B5ES or BP5ES which is a projector nose plug but does not come into contact with valves or piston. However, before you do anything more just check the spark off the bare end of the HT lead . F12s that run perfectly well never seem to have a "cracking spark".

A Meco unit works fine on an F12 but is not a magic cure for a bad coil. Personally I would get the engine running properly before fitting the Meco. 

if the engine does not pull away from the top shaft you need two heavy hammers - preferably copper / lead or deadblow and with the the mower on the ground straddle the machine and   hit the flywheel simultaneously  at 3 and 9oclock towards the engine, then rotate the flywheel quarter of a turn and do it again and again ....... Remember to unbolt it first!!  

Doing a valve job is easier with the engine off the machine but can be done with it still attached to the top shaft. If you remove the handle bars, unbolt the engine then lift the back of it so that it rotates forward, then  put a wooden block under it the valve chest is more accessible. A block under the rear roller makes it even more so.

 

RickT
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Thanks for the advice

Thanks for the advice Wristpin - gratefully accepted.

I'll have to have a word with the local mower repair specialists - they sold me both suppressor cap and spark plug! My Mk4A has the isolation cut/out switch with a cap.

OK I'll try with the contact breaker solution first and will investigate rotating the engine on the chassis as advised to gain easier access to valve chest - even if it does mean leaning down a bit more than when on the workbench!

Thanks again.

RickT

 

wristpin
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"Workmate" height is about

"Workmate" height is about right for the valve job but if you are doing the hammer job on the flywheel you need to be able to get the simultaneous strike.  

NM
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Can you put a couple of thin

Can you put a couple of thin wooden wedges on one side between clutch ring and flywheel and give engine a good yank from opposite side on engine to the wedges. May not be well explained but I’ve done it to make it lighter to lift in and out of car.

P.S. Sometimes the shaft bearing stays on the shaft and sometimes it doesn’t.

wristpin
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By clutch ring do you mean

By clutch ring do you mean the clutch drum?  If so, I would be concerned about distorting the drum .

NM
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Hi wristpin, yes I did mean

Hi wristpin, yes I did mean the clutch drum but thought I’d check in the manual for the proper (Ransomes?) term.

I can’t detect any distortion but anything is possible and it seemed the best way to make things lighter when loading/unloading in and out of the car. I managed to pick one up complete but my back was a bit delicate for a few days afterwards it was a bit of a lean in and lift operation.

RickT
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Apologies for this delayed

Apologies for this delayed post following a successful outcome early September.

Rotating the engine without removal gave me the access to the valve springs and following the required juggling of 2 screwdrivers I was able to remove the pins and grind/re-seat the valves. A third hand helped to reinstall the valve spring pins.

Following the rebuild of the carburettor and soaking/oiling of the air cleaner plus fitting a new foam air filter I returned my attention to the ignition.

Despite previous imaginations and producing 'perfect' contact breaker surfaces and gap I  could not get any spark even with the end of the raw plug lead. So I guessed that either the coil or condenser required replacement. As I had already procured a Meco electronic ignition unit I fitted it rather than spend the same money again for a replacement condenser - the cheaper of the two components that might have failed.

Success! Sparks appeared!

I then refitted spark cap and plug, added fuel to the previously flush cleaned tank and waited for fuel to fill carburettor.

Full choke - 1st pull - nothing. 2nd pull - nothing. A little disappointed at this time. But on 3rd pull the engine fired and ran perfectly as I gradually removed the choke. Big smile on my face!

I lowered the tickover revs below clutch engagement speed and watched it tickover for many minutes (it's a great sound!) before I decided to release the drive 'clutch' and mow a strip of lawn. Blades need sharpening! It also seems that at high revs you would have to run to keep up with it - or have much longer legs than mine!

I am very pleased with the result. I still have to complete the cleaning and oiling of 'grease' nipples and then I wil be looking for a deserving recipient and clear some space in the garage.

Thanks everyone for their advice and guidance.

RickT