Suffolk Colt Mower.

Hi,

It's now 4th June in West Yorkshire and the usual miserable wet black hole so I'm a keyboard warrior once again to stop me moaning.

Last Saturday I visited Rufforth Auto Jumble in York and whilst wandering around noticed two old petrol mowers on a stand; I went over to have a look and as the seller wasn't too active I walked away; a little later I found myself once again drawn towards these mowers and looking at them whilst already owning two petrol mowers do I really need a third petrol mower so I walked away again; a little later I was attracting massive attention to myself as I pushed one of the mowers to the car on the tarmac creating a huge amount of noise but I'm not bashful; at the car I was emptying the boot of the items I'd already bought and was about to try lifting the heavy mower into the car when two passing guys very kindly asked if I needed a lift which I thankfully accepted; with everything loaded I did another circuit before setting off back home.

I had dinner first then donning my workshop clothes I headed down to the workshop and taking a deep breath managed to unload the mower. I paid £20 for the mower and thought it's well worth the money just for me to tinker about with it because I love these kinds of projects.

I removed the handles then lifted the mower onto the bench to have a good look at it; the mower is complete but in a sorry state needing lots of TLC so it's welcome in my workshop. The starter cord and handle were hanging loose and the starter was jammed solid so this was first to look at; as I removed the cover the cord suddenly rewound but I heard something rattle it's way to the bench; it was a machine screw and spring washer with almost stripped threads so it was this jamming the mechanism but where had the screw come from. I didn't have a parts diagram but after a bit of searching it became obvious the screw was meant to secure the spring unit? I washed the spring unit in paraffin and will sort the wayward screw out later.

Yesterday I managed a couple of hours in the workshop and did a bit of stripping; the petrol tank cap was welded solid with rust refusing to unscrew even with pipe grips to lever it but I didn't want to damage it so I applied lots of heat knowing there wasn't a drop of petrol or petrol vapour in the tank; finally the tank cap was on the bench; next the engine covers were removed followed by the cylinder head with a sketch made of the head bolt positions; two bolts were extra long to accept nuts one bolt had the spark plug guard secured by it; I've worked on engines for the last 55 years but I always take notes and make simple sketches as I do any stripping; it takes less than five minutes for me to forget where parts are fitted? I also take lots of digital images for future reference.

WOW; it sure looked rough with the head removed; I had turned the engine over very easily by hand there being extremely little compression and now I found the reason; the exhaust valve was stuck fully open. I turned the engine to give maximum valve clearance and using a dead blow hammer gently tapped the exhaust valve after firstly spraying inside the exhaust port with WD 40; after a few taps with the hammer the valve reluctantly moved a bit so I then kept turning the engine over to lift the valve then tap it closed; lubricating oil was now added and eventually I was able to apply thumb pressure to the valve whilst turning the engine over working like this until the valve worked with its spring pressure; force must never be used in order to prevent damage; gently does it.

I decoked the cylinder head and knowing how easily aluminium cylinder heads distort decided to grind in the head joint face; I've done this many times and all I needed was a flat surface and sheets of wet or dry abrasive paper. Initially I tried using 400g with paraffin as lubricant but it was slow going so I changed to 150g and worked steadily away using the band saw cast iron table as the flat surface grinding in a circular motion; as expected there was quite a bit of distortion; I didn't want to remove too much material but removed enough to allow a good head gasket seal.

I've been prevented from doing more work on the engine today but with luck I'll resume work tomorrow morning. I need to remove the valves and grind them in also to decoke the valves and ports.

I've ordered a new spark plug which arrived today; new Suffolk Colt Decals from Australia and 10m of starter pull cord also a new petrol tank tap these still to arrive; a quick check and I couldn't see a spark so it's definitely interesting.

Kind regards, Colin.


The mower as bought still with grass clippings looking better in the picture than it actually is.


Carburettor controls seized solid; the fuel hose was severed with an hacksaw; new hose and tap ordered.


The machine screw which was jamming the starter mechanism should have been tight in the center hole but it has a mostly stripped thread so a job to sort later.


Showing its age but the spring is fine and it all cleaned up with paraffin making it look better.


The petrol tank filler cap was very difficult to remove due to it being rusted solid in position.


Something out of an horror movie; it sure looks grim with the exhaust valve stuck fully open.


The cylinder head also in equally rough looking condition.


Most of the decoking done to the cylinder head and initial grinding showing the high spots.


Cylinder head joint face grinding underway using the bandsaw cast iron table as a reference and paraffin as lubricant on the wet or dry abrasive paper; I've done this kind of work many times during my biking years whilst restoring motorcycles.



The same cylinder head looking a great deal better; checking against a straight edge engineers rule it's now flat. What a lovely project whenever life allows me to get to it.

 

Hi,

I've enjoyed a rare day in the workshop today without interruptions so a bit of progress has been made on this mower engine.

To make life much easier I removed the engine making it easier to work on; the mower body then was put out of the way freeing up bench space. The silencer was full of water but was removed without too much trouble; the carburettor manifold was removed and the pile of bits started to stack up on the bench. I was keen to remove the valves and these proved a bit of a pain to remove because they were held in position by small diameter pins and these pins really needed long nosed pliers to aid their removal but after a struggle the valves were sitting on the bench; I've been restoring engines for over 50 years but these valves were by far the worst I've ever seen.

One thing I've not come across previously are unequal length valve guides the inlet guide protruding well into the inlet port whereas the exhaust valve guide end was flush? What an absolute mess this engine was in; water ran out of the exhaust port when the valve chest cover was removed but no way could I make it worse so not to worry just sort it out taking my time; the exhaust port needed decoking but the inlet port was quite clean after a wipe.

I gently used a craft knife on the valves to remove rust and carbon then used the Graduate lathe to spin them allowing abrasive paper to make a decent job; the inlet valve cleaned up nicely but the exhaust valve is badly pitted; I could have skimmed the exhaust valve in my Lorch engineering lathe but I didn't want to remove material so polished it best I could.

Next job was to grind in the valves; as expected the exhaust valve took quite a bit of grinding but the inlet valve was done quickly; once a continuous ring appeared on the valve and valve seat the grinding was complete and I was pleased with the result; only fine grinding paste was used. Before fully installing the valves the valve gaps will need checking; a ribbon of clean cloth was pulled through the valve guides to ensure they were clean then the guids were lubricated; both valves now open and close under their own weight without the valve springs; the cylinder bore was wiped clean then clean oil applied; a bit of TLC definitely works wonders; next session I'll gap the valves and install them together with the cylinder head; this will take care of the missing compression then I can concentrate on the missing spark?

I sprayed the engine with WD 40 and brake cleaner so now the engine looks like someone cares about it. The new petrol tank tap and hose arrived this morning so it's coming together.

Kind regards, Colin.


What a mess so it can only get better.


Any sane person at this point would scrap this mower.


A close up of the valves; the exhaust valve on the right had suffered water damage and was only suitable for the bin?



I'm stubborn; the inlet valve on the right cleaned up nicely but the exhaust valve less so.


For members unfamiliar with grinding in engine valves this is the method used and is quite easy with a little practice; the valve being ground in needs to be fully closed then a smear of grinding paste applied where it seats on the port; the valve tool sucker is wetted with a drop of spit then pushed tightly onto the valve head; suction then holds the sucker in place but not for a novice as there is a knack to this; with the tool as shown both hands are rubbed together with the tool handle between them rotating the tool and valve; at first the sound is coarse but quietens as grinding commences; I like grinding in valves and as soon as a continuous shiny ring appears on both valve and valve seat the grinding is complete; all traces of grinding paste must be removed; on these side valve engines the valve gaps now need checking and if tight need very careful grinding to shorten the stem length but this takes skill because it's incredibly easy to remove too much metal resulting in a wide valve gap. I've a feeling installing the springs; retaining collars and securing pins will be a test of my patience but with the engine on the bench it should make the job a bit easier. With the valves reground and back in position; the cylinder head can be refitted; the engine won't then spin over freely because it will now have plenty of compression.


Basic tool with grinding paste; I've used this method for well over 50 years.


What a difference; the exhaust valve remains pitted but now has a continuous ground sealing ring so it will do its job.



Both valve seats nicely ground.


A good clean makes a lot of difference.



Quite a bit of work but well worth it and who would ever guess what it was like before receiving a lot of TLC. These projects are so rewarding and hopefully this engine will sing once again.

 

Steady on @Retired, you'll be blueprinting the engine by the end of it and testing it on a rolling road for BHP output !

 

Hi,
Many thanks CarolineL; I can tell by your reply we're kindred spirits.

I had considered polishing and gas flowing the ports then installing an high lift spitfire cam; 10.5/1 piston then a supercharger with big bore exhaust; I don't want to go mad after all it's only a mower but if a job is worth doing it's worth doing right?

Unusually this morning was gorgeous weatherwise it being like a summers day with the sun shining; my personal cloud Blackie wasn't putting down rain but his sister Gale was certainly on form; her stiff breeze sure was cold. I couldn't waste such a day playing with the mower so I headed up the mountain to attack the big hedge at the top.

Here's today's interruption to me having fun and I'm hot having just taken a full load of debris to the tip;


Why enjoy myself in the workshop when I can tackle this 60' long hedge instead; this is into our garden and now trimmed back; I forgot to take a second picture.


Work well under way from the lane; the car is abandoned possibly broken down and the driver has been considerate enough to park it right in our overhanging laurels; last night I informed the police of the cars presence because idiots use this lane like a race track and it poses a serious accident risk. Enough of this being idle after all I'm 71 and retired without enough hours in a day. Heavy rain is forecast for tomorrow so I might get some quality workshop time in?

I spoke too soon; Blackie and Gale waited until I reached the top of the garden then Blackie gave me a downpour soaking me whilst Gale added a chill factor trying to blow me over; at least it's June and it could be a lot worse.

 

Supercharge? Not simply turbocharge? And surely the cam will make it a bit peaky - means you'll be running around the lawn just to keep it in the right rev range
My sympathies re the laurel hedge - they are hard work. Got rid of it - towing roots out with a landrover.

 

Hi,

Thanks CarolineL; fitting a turbo would be too easy and I never do easy? Yes the rev range would be peaky but just what I want because of my personal black cloud called blackie; I have to dash out and do jobs before Blackie spots me as he did yesterday with a very sudden short downpour soaking me.

Yes laurels are a real pain once they mature; ours reached 30' tall but I was too busy working on the bungalow to do anything about them; once the bungalow was finished I started on the gardens and attacked the laurels with my petrol chainsaw bringing their height down to under 4' where I can now talk to them; at the top of the garden though the laurels are kept taller to ensure our privacy. You did well to drag yours out with a Land Rover; our laurels are so big they would damage a Land Rover. The school run should be over by now so time I wandered up the mountain and get cracking; I just hope Blackie leaves me alone but I doubt it because he's hovering just waiting for me to go outside.

Kind regards, Colin.


I never do "easy" here's one of our 80' tall firs I felled and disposed of; I felled two of these plus others like oak and mountain ash; all this work means I don't need a gym; I'm 6' tall and built like a stick insect at just over ten stones; I never ever put weight on.



Ladders up the tree; attach a very long rope; use the petrol chainsaw to almost cut through; put the chainsaw safely out of harm's way; go up the mountain and give the rope a powerful tug; watch the tree heading my way and hope the rope is long enough; felling is easy; disposing of the tree hard work; trunk and heavy branches cut into short logs for wood burner owning neighbours who were delighted to receive free logs the brash was shredded. It upsets me to fell such trees but they become a danger when so tall and in close proximity to our bungalow.



Nothing is easy living here; Whomever planted ivy in our gardens didn't do me a favour; here's an ivy more like a tree damaging the dry stone wall; a bit of weeding doesn't cut it for me.

 

Hmm, that is gardening on steroids...

 

Hi,

Couldn't agree more CarolineL. It's a job for superman but unfortunately he's busy so it's down to me a ten stone weakling; fortunately I'm still quite young at 71. Bron says the SAS could train here?

I might get into the workshop tomorrow if Blackie doesn't wash our bungalow from the valley side; the rain sure is coming down and if this is light rain it's a good job we aren't forecast heavy rain?



Kind regards, Colin

 

Hi,

I've not got into the garden at all today due to the rain so I've enjoyed a few hours in the workshop shutting the world out.

My valve spring compressor wasn't suitable to compress the valve springs on this engine so I suffered lots of frustration but the valves are now in so another job completed.

I then investigated no spark? At first I couldn't obtain a resistance reading through the magneto so I removed the ignition points and gently pulled some 400g abrasive paper through; now I found a reading of 11.7K Ohms which looked promising; with the new spark plug connected I could spin the engine by hand it still not having its cylinder head refitted; I couldn't see a spark so I turned the workshop lights out and now I could see a spark; I've ordered a new head gasket and when this arrives I should then have compression and spark so the engine should fire up but I'm now tidying the mower. Tomorrow I might have a go at the carburettor because its adjusting screws are locked solid and it looks pretty rough; hopefully I'll have the mower running soon.

50 years ago I used to make my own cylinder head gaskets from copper whilst restoring motorcycles.

Anyone following this please note the flywheel retaining nut has a left hand thread.

I wandered up the garden at dinnertime today and at last the car on the lane has gone but now I'm unable to complete the hedge trimming due to the rain; GRRRRRR.

Kind regards, Colin.

 

Your painstaking work reminds me of what my dad used to do. He loved to take dodgy mowers apart, with all the nuts, screws and parts carefully lined up in order (no phone cameras back then to enable reminders) and bring them back to life. These days most devices are sealed or have 'non-replaceable parts' to encourage you to chuck them away.

 

Colin. A man after my own heart. Ages since my hands smelled of petrol and grinding in paste. I have some great memories of this kind of interest.

 

Hi,

Thanks CarolineL. I was taught the old fashioned way by old fashioned very highly skilled engineers and as you rightly say no phone cameras back then in fact no electronics at all; we used manual lathes and other machines working to very fine tolerances using micrometers. Our cottage didn't even have electricity until I was five years old and a single open coal fire to heat the entire cottage; poverty was real. Yes line everything up; I still use card or string to keep components in order; things like head bolts pushed through a piece of card or stout string if stripping say a gearbox to keep gears; bearings and spacers etc in order; actually I still prefer this to relying on digital images it being virtually foolproof; I take many images though of every job I do just for future reference and they are handy for sharing with friends around the world as well as posting on forums.

I've only recently got into petrol mowers;my chum was having lots of trouble with his petrol mower it starting OK but then dying after five minutes; he was convinced it was a fuel problem aided by many YouTube videos; he checked the tank cap vent; changed the air filter; changed the oil; bought a carburettor diaphragm; cleaned out the carb; installed a new spark plug but still the mower died; he bought a second diaphragm then even bought a brand new carb; by now he had run out of time to play with the mower so bought a brand new Honda mower and kindly gave me his troublesome mower to play with; I know he's fastidious in everything he does but I did say I wouldn't buy a new carb to him.

My chum lives in Hull 70 miles away so it wasn't a case of just popping next door to give a hand. I had also suggested he having carried out just about everything on the fuel side it could be an ignition fault but as I say he ran out of time and I collected the mower from him at Rufforth Auto Jumble where we try to meet once a month.

Back home with the mower I ran it and sure enough it died after five minutes running. No way was I going to simply follow my chums work so with the mower on the bench I did a bit of electrical testing on the magneto and checking the cut out etc; I believe the mag was giving an healthy resistance reading of 6.4K Ohms and yes it had a spark but I was unfamiliar with these mags so I spent ages on the web trying to find a mag circuit diagram which I did eventually find; as soon as I saw the mag contained and SCR (Silicon controlled rectifier) I bought a new mag and now the mower is fine but I also decoked it and ground in the valves; a brand new mower bought just because of a faulty magneto. I'm used to working with SCR's knowing the ones I used needed a big heat sink otherwise they would surely fail if becoming too hot just as in the case of the mower; most of the YouTube videos though pointed to fuel problems; after I had sorted the mower out there are YouTube videos well one anyway showing this magneto fault but it needs searching for.

Thanks Mike; yes it's great fun to have dirty hands and smell all the workshop aroma's isn't it; I bet you've played around with motorcycles too? Grinding paste; Solvol Autosol; Gunk and of course cellulose fumes both from brush and spray I used to buy small tins of brushing cellulose from Halfords these had a small brush attached to the inside of the tin lid (Belco). Happy memories indeed.

I've just enjoyed a mug of tea but I need to head back up the mountain to carry on working; I've been grafting again sine early this morning and I want to beat the rain before it pours down again.

Kind regards, Colin.

 

Hi,

Back to the mower; I've spent a bit of time on the mower making a bit more progress. Having now sorted out the valves and surfacing the cylinder head flat I decided to treat it to a new head gasket so bought the new gasket through eBay.



With the cylinder bore lubricated it was a simple job to replace the cylinder head. The engine now has lots of compression. Now I could have a look at the carburettor; releasing the seized adjusting screws and float tickler proved time consuming; the big adjusting screw however proved a real pain to remove; I ended up applying lots of heat from my electric heat gun and finally the screw moved but refused to unscrew; I spent ages using pliers gently rocking the screw backwards and forwards taking lots of care not to break the screw. eventually I had the screw out and unfortunately it had damaged the carburettor threads; the screw had two aluminium threads adhering to it and these were the cause of the problem. I needed an engineers tap to clean up the carburettor body thread but although I have a large selection of these taps I didn't have the correct size.

I visited a local engineers supply store and asked for a tap please this size handing over the adjusting screw; I must have been in the store twenty minutes; after lots of checking against thread gauges the thread was a rather odd size at M5 x 0.75 I've got M5 x 0.8 and so had this supplier; he got on the phone and some time later said he could order a tap for me it would be available the next day at £14? £14 for a single very small tap I'm sorry to have wasted so much of your time and thanking him I left the store.

At home I browsed eBay and sure enough these taps were available but still at around £14. Never mind I don't need a tap I'll just buy a machine screw and convert the screw into a tap? Because I wanted a machine screw with this thread they were extinct; I didn't want to spend ages playing with change wheels on the lathe so browsed the web a bit more; Tracey Tools had the tap at £3 plus postage; this was a carbon steel tap not like the others at HSS ( high speed steel) carbon steel would be fine after all I'm only cleaning up a thread; what a palaver; I've used these taps for over 50 years but this one was frustration; when the tap arrived it took seconds to to run it into the carburettor body and what a surprise as I withdrew it bringing a lot of debris out; whenever I'm doing this kind of work I progress very gently otherwise lots of damage could be caused.


The adjusting screw. M5 x 0.75.


I went through thousands of screws and couldn't find a single screw with the correct thread; Above is just a sample of the stock of assorted screws I have to hand.



The carbon steel tap from Tracey Tools only costing £3 plus postage.


Gently running the tap down the thread taking a lot of care not to cross thread.


This is the reason I was so keen to do this job correctly; forcing an adjusting screw is just asking for trouble.



The carburettor ready for service.

Now I could check the carburettor and removed the float bowl together with the float allowing the bowl to be cleaned out. With the jets blown clear and everything now working as it should the carburettor was reassembled; just the manifold to check next. It's amazing the amount of time a simple job can take to accomplish but I'm not in a hurry. Second hand carburettors are available through eBay at around £28; I only paid £20 for the entire mower.

I want to tidy the mower body before refitting the engine.

Kind regards, Colin.

 

Hi,

Rain and miserable outside but a pleasant morning in the workshop getting my hands dirty.

I'm very impressed by how these mowers are made and the engineering involved; Modern machines are seldom as robust as these old machines when high quality meant something and workers took a pride in what they were doing; few tools were needed to strip this mower and it came apart without a struggle; reminds me of my motorcycle restorations. I've enjoyed this morning.

It might be regarded as just an old mower but to me it's a well made machine and deserves respect.

Kind regards, Colin.


A good clean with paraffin will make it look better.


After cleaning most of the dirt away I might as well make a good job of it.


The clutch drum needing some TLC before it's refitted.


I wondered how these mowers came apart.


Now I know how these mowers come apart.



The bearings will enjoy a good clean and being greased.

 

@Retired Thanks for posting this thread, I've enjoyed reading through it.

One of the things that fascinated me was the fact that we use different methods to do similar jobs. For example, I would lap in a head using valve grinding paste on ground glass. Rather than buy a head gasket for a sidevalve, I would make my own using some of my rapidly depleting stock of Reinz SS.

One question though. Are you certain the thread was M5x0,75? The usual thread on a mower that age (assuming it is old enough to be made using non-metric threads) would be 10-32.