Lawnmower engine

[peterd51]

Hi,

I'm still using that brilliant Ebay search for local items (within ten miles) that are 'collection only', and last weekend I picked up a Suffolk petrol lawnmower for £10.50!

The advert stated that it had been running but not very well before it stopped and he thought there may be a spring missing off the carb. Obviously that put most people off so I got it cheap enough that we can play around with it and if we don't get it running it's not a disaster.

Earlier today I had a go at it with my middle grandson...

the pull start wheel was spinning so free that I thought maybe the con-rod was broken but after popping the sparkplug out we could see the piston moving. I thought it was 2-stroke but then noticed that it has a dip-stick. After removing the cylinder head I found it's a side-valve engine...haven't seen one of these since my old mates BSA (around a '54 model as I recall) and that must have been 30 years ago!

It looks to me like someone's played with it and not connected up the throttle cable to the actual 'valve'. The part that it was on looks more like an achor point on the manifold that was loose so it looked like the cable was actually doing something while the real valve is on the carb itself with nothing attached to it.

Anyhow, the engine's off the mower, we've got a decent looking chain and a centrifugal clutch. Looks like a decent stripdown and clean will get it running, maybe by next weekend.

I guess it's around 50cc but does anyone know for sure if it is, if it's 4-stoke, etc? Can anyone point me at a photo of the carb/throttle cables or advise on what it should look like? I've done a google search for 'suffolk lawn-mower' and 'E8103', the engine model number ,but haven't found anything usefull.

If we get it running then we'll be strapping it to go-kart/buggie/bike of some kind...maybe scout around the car-boot next Sunday to see what we can find!

Regards
Peter

 

[shenion]

The throttle cable usually just pulls a spring. That connects to the carb butterfly and also the governor. Here's an example:

Post some pics, I work on a lot of these.

If it has valves, it is a 4-stroke.

 

[peterd51]

Hi,

strewth, that was quick...

I've just been out playing around now that my grandsons gone home. It's great having him here and showing him stuff but there's not enough 'thinking' time, it's all got to be done 'now' and there's always another question!



The ball on the cable 'A' was attached to the lever 'B' but there's nothing inside the manifold at that point. 'B' moves back and forth but doesn't actually do anything.

The other lever 'C' has the valve on and it's shown here in it's closed position, ie, tickover. The end of lever 'C' nearest the camera, with the hole near the end, needs to move towards the carb-body to open the throttle. What I can't see is if there was a spring between 'B' and 'C', how moving 'B' towards the carb-body by moving the throttle on the handlebars would cause 'C' to move in the right direction to open the throttle. It's like it set up in reverse.

If the cable was attached through 'C' and was then anchored at 'B' then tightening the cable would open the throttle, but then why is there a hole and adjuster in the flange where the cable is currently going? I'm sure I could figure something out but it'd be nice to get it working as it was intended to.

I've managed to get a spark out of the plug, so that's good news, it doesn't have a broken dynamo, etc. Also I measured the bore (50.21mm) and stroke (39.12mm). doing some simple maths, pi*R*R*L/1000, I get 77.48CC.

Allowing for the area where the valves are I guess an 80cc engine? Seems an odd size as I expected 50cc. Or have I got the maths wrong?

Regards
Peter

 

[shenion]

Most likely 'B' connects to a governor via a spring. Then that has a bar that runs to C.

 

[peterd51]

Hi,

looks like I need to sort out some springs and brakets then.

I'm hoping to limit whatever it's on to 5 mph or so, it'll be either on or off with nothing much in between, so I shouldn't need to worry about being too fancy.

Regards
Peter

 

[Shox Dr]

I love deals tis better to have and not need than to need and not have

How do you search on items "local" to yourself

 

[peterd51]

Hi,

the search string is:
(("cash on collection", "buyer must collect", "collection only", "no postage", "pick up only", "unable to post", "needs to be collected", "Collection in Person only", "can't post"))

if you go to the advanced option there's a tweak to select 'items near me', you add your postcode and specify the distance (10 miles in my search). You get to see everything that's too big to post, so it includes all sorts of stuff that you'd maybe never think of searching for.

And it works out pretty cheap as long as you don't go crazy!

I keep telling Bobbie (the wife) that it's only pocket money if it's less than a tenner...

I also bought a Teddy Grabber for 99p. The cabinet's six feet high and four feet wide as it's a double grab version so it's parked in the garden with a tarp over it. It sort of works, it powers up anyway, and the previous owner thinks there may be a fault on the end of line switches but he's not into electronics. Something else to play with when the grandkids are with me on a weekend.

The previous owner said he'd had interest from Kent and London but it was too far for them to travel and both punters asked if he'd strip off the circuit boards and mechanical bits but he didn't want to get involved with that. Even if I can't get it working I could re-advertise it stating that I'll strip it and post the parts and I could get 10x my purchase price on it (these things are a couple of thousand pounds new).

Regards
Peter

 

[bill_gj]

Peter - I've lost my link for the thread that had that ebay search tip - any chance you can post it up again?

 

[peterd51]

Hi,

Peter - I've lost my link for the thread that had that ebay search tip - any chance you can post it up again?

yes, it's in my previous message...

Regards
Peter

 

[bill_gj]

Ahhh.....the Donkey virus has struck me down, That's my excuse anyway. Thank you for your tolerance.......slinks away chamefully

 

[GeorgeB]

Peter - could you please take a further photo which is (a) more in focus and (b) not as dark, so it's easier to see the details of your carb. I have two of these engines and one looks a bit like yours but I can't really tell, from your first photo.

 

[Batf1nk]

http://www.localbargainfinder.co.uk/

Follow this link and put your postcode in. Will search for local bargains for you.

 

[peterd51]

Hi,

http://www.localbargainfinder.co.uk/Follow this link and put your postcode in. Will search for local bargains for you.

That's where I 'borrowed' the search string from, I think.

I've taken the head off the engine and cleaned up with degreaser and fine wet and dry...



The carb had a small amount of rust at the bottom of the float chamber so I cleaned that up the same way. Externally I've cleaned everything with a paint brush and degreaser.

If I get chance on the way home this afternoon I'll call into the lawnmower repair shop with the carb and see if he's got a new throttle cable and some springs. I'm planning to drain the engine oil tonight and flush out, the engine tipped over on the bench, dropped some oil and there's either water or fuel floating in it.

Hopefully my son will supply some petrol soon, next time he fills his car he's going to squirt a pint into a can for me. We're all running diesels at home!

Regards
Peter

 

[pete3000]

here you go Peter

http://www.oldlawnmowerclub.co.uk/detlistbyeng.asp?Manufacturer=Suffolk

I recognised the choke/carb section you showed. I have an almost indetical mower engine, so let me know if you need photo's/measurements.

I haven't done much with it though as it is only 1hp. You can get the engines now with 3.5-4.5hp so I am on the lookout for one of those.

Pete

 

[peterd51]

hi,

Peter - could you please take a further photo which is (a) more in focus and (b) not as dark

It's a bit tricky with the sun being so bright and the carb being a bit tiny, but this looks a bit better...



Thanks
Peter

 

[peterd51]

Hi,

http://www.oldlawnmowerclub.co.uk/detlistbyeng.asp?Manufacturer=Suffolk

Thanks for the link. It looks like I have a 12" colt...

must be a joke in there somewhere!

Anyhow, it's now as 'stripped' as it's going to be and I flushed out the crankcase. The lawnmower shop in Scunny has closed down, so I'll have a search around Yell, etc, later to see what else I can find. I know there's an old motorcycle shop uptown and they keep all sorts of cables, nipples (screw and soldered) and springs, etc. I'll get something working.

I had an idea on my way home from work tonight...I don't have to fit the throttle cable the original way around. If I make a bracket and reverse the cable run then it'll pull the throttle open and I just need a big spring to flick it shut when the power's turned off.

I've loosened the throttle lever too, so it has to be held open and with a big enough spring on the carb it'll 'snap' shut if you take you thumb off it...a safety device for the grandkids in case it gets away from them.

Regards
peter

 

[GeorgeB]

It's a bit tricky with the sun being so bright and the carb being a bit tiny, but this looks a bit better...

Thank you for the updated photo. I think the carb off my fully operational Suffolk Punch lawnmower is somewhat similar, as shown in the following image. I hope this helps in terms of how the cable is fitted, where the spring goes, etc.

 

[peterd51]

Hi,

nice, thanks.

I guess there's a lever under the red cover and the cable pulls the top of it...then the bottom of that lever pulls the rod that goes to the carb?

That top lever on mine had the cable attached to it, the cable's not long enough to go anywhere else, and it waggles back and forth where on yours it looks more like a 'guide' for the cable inner and somewhere to attach the return spring?

I think on mine it was designed to pull the top lever and the spring would take some of the 'sudden' movement out of it to open the throttle gradually...

I can make something like that work!

Regards
Peter

 

[pete3000]

The cable stop end should be fixed to that bracket with a spring clip, it doesn't connect any where else.

The choke is the quarter turn brass thingy before the wire wool air filter on the round tube end facing downwards.

The solid rod which goes under the cover is a governor linkage. the screw adjusts the slow running idle. against the body of the carb. on the rod is a very light spring to hold throttle closed. The rod then goes to a pivot and thin alu sheet flap against the flywheel fins which moves to regulate the engine speed under load. Faster on thicker grass as the engine slows and slower to close the throttle as the engine flywheel speeds up.

Pete

 

[wyn]

As pete says the cable going under the red cover could be a bit misleading. If it was fixed to the arm on the governor, the governor wouldn't be free to move on it's own ( govern engine speed).......But the engine would probably still run reasonably ok.

It should fix to the arm with the various holes in it.


This carb on ebay gives a good idea of the linkage and the spring connected to the loop in the middle of the linkage.