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Collection, Preservation and Display of Old Lawn Mowers

ATCO Balmoral SE starter fails to engage - now hunting

I have just become the owner of the above mower and it is great.  The only issue is that when you use the electric start (I have a new Battery) it fails to engage with the flywheel, it just spins against the wheel; the pull start is fine but as it is a new toy, would love to see how it works!


Is this a known issue and do you have any recommendations on how to fix it.




wristpin Wed, 26/10/2016

An image of the starter bendix will help but I suspect that the drive from the starter armature shaft may be transmitted to the pinion via a "rubber" friction buffer and if this is either worn or contaminated with oil it may be slipping. Also check that your "new" battery is fully charged.


Should have asked is your machine one with the Mitsubishi engine or one with Atco  /Suffolk's own?

ATCO B17 Wed, 26/10/2016


Thank you for the reply, it is a bit 'greasy' and there is some rubber so you may be correct; i will have to look and see if it can a) be cleaned or b) how to replace the rubber.  I believe it is a tecsmseh 148cc engine but hope the photo will tell you more.

         Sorry about the orientation!

wristpin Thu, 27/10/2016

Yes, that is the Atco/Suffolk engine which I believe is derived from a Tecumseh design although that has been the subject of some debate on this forum..

Make sure that the pinion is free to move up the spindle and clean any oil and contamination from the friction faces between the buffer and the pinion. A rag moistened with brake cleaner or petrol should be sufficient.  Make sure that the battery is fully charged so as to give the initial kick to get the pinion moving toward the ring gear and to apply the required pressure to transmit the drive .

ATCO B17 Thu, 27/10/2016

Brilliant, thank you. I will try that and let you know how it goes. I think I oiled it to help it but was obviously the wrong option. You live and learn. 

ATCO B17 Thu, 27/10/2016

Wristpin,  That seems to have done the trick, all cleaned and it engages and turns engine.  It is not a 100% but I guess that having not worked for a while, it need time.

I foolishly fed and seeded the lawn so can't try it out in anger yet - never mind, they say patience is a virtue!

Thank you very much for your help.



hortimech Thu, 27/10/2016

No, that isn't a Tecumseh derived engine, it is a Tecumseh engine laugh

It's the earlier A98 & A114 that were made by Atco/Suffolk.

The bendix drive should move freely up the starter shaft and probably shouldn't be lubricated. You can get a similar problem problem with B&S starters, the plastic gear gets contaminated and wont throw out, though it could be, as Wristpin pointed out, a flat battery not spinning the starter fast enough.

ATCO B17 Thu, 27/10/2016

Hortimech, thanks, that will help if I need new parts.  The starter/'bendix drive' spins and throws the gear but it is a bit hit and miss about engaging (whirrs fast and makes a nasty noise); has engaged a few times.  All very clean now but will charge the Batt (it is new) again to confirm.  Might show it my biggest hammer just to scare it into submission!!!

Got a new grass box - no bracket Ahhhh - now got to find one of them!  as a bit of background, I saw it in a friends driveway, asked to borrow it (as it had a scarifier) and he said "have it as I am chucking it".  Fired up 1st time.  What a find but had to get a cutter, grass bin, a puller top and air filter.  All sorted (even changed the oil myself!) but didn't know about the support for the grass box - must look at pictures more carefully!!!

wristpin Thu, 27/10/2016

I'm not going to get into a further disagreement re the origin of the engine but I'm fairly certain that it was not a "main line" Tecumseh but a special build for Atco/Suffolk. The only of the shelf 148cc of that era  that I can find listed is the H30 which as considerable detail differences from the engines supplied to Atco/Suffolk. The other thing to bear in mind is that Tecumseh withdrew from engine and transmission manufacture in 2009 . Husqvarna bought their transmission designs and manufacturing rights and the rights for certain engines were sold to the Certified Parts Corporation of Janesville, Wisconsin. I have no information re the current situation.

On a brighter note, you may find this of interest.…

Note that the component that I've referred to as the "rubber buffer" is more correctly termed the pinion driver.The other thing to note is that the scan applies to European made product with European part numbers . US made product used its own part numbering system. Your "nasty noise" suggests that the pinion is bouncing off the ring gear - not good for either. It again suggests a less that good battery. If you are sure that the battery is good try checking all the electrical connections, particularly the battery earth and the starter's mounting to the engine. If the cables allow it take the battery earth directly to one of the starter's mounting bolts and clean off any paint around the cable contact to the motor.

ATCO B17 Thu, 27/10/2016

Wristpin, I think I am staying out of the engine debate, I have enough problems trying to start it!!

Thanks for the diagram, at least I can put it back together in the correct order now (I may have put 17 and 2 the wrong way round after cleaning (up-side-down)!!); I will check the earth.  The Bat is new so will ensure it is full charged.  It has engaged a couple of times so I am nearly there, a few tweaks might just get it perfect.  I agree the noise does not sound like it is doing the machine good so will desist from that.

Could the mount be misaligned, causing the direction of the thrust to be out?  The hammer may yet get some use!!

hortimech Thu, 27/10/2016

I never said it was a mainline engine, but it was manufactured by Tecumseh. Tecumseh stopped making engines abruptly in 2009, Ariens was one of their biggest customers and used the engines on snow blowers, Dan tried to buy Tecumseh but was unsuccessful, so started using other engines. CPC, with LCT, is, as far as I am aware, still making Tecumseh engines.




wristpin Thu, 27/10/2016

Good point about the mount. If the starter has had some abuse in the past it could have been kicked away from the ring gear. Eye it up and check that the pinion shaft appears to be parallel with the engine crank and that the pinion teeth are engaging with the ring gear teeth fully but not bottoming in them. If the teeth are only just engaging you can possibly "tweek" the starter motor in-situ to obtain better engagement .

Something to be aware of that the variety of starter motor used is of the permanent magnet type with a ferrite magnet ring or magnet sections bonded to the inside of the starter body. When working on them the tubular body should NOT be held in the vice as there is a danger that any distortion may break the bonding between magnet and casing and ruin the starter.

Perhaps it's just less hassle to pull the rope!

ATCO B17 Fri, 28/10/2016

Thanks,  I will play with the adjustment, probably just for my amusement and yes, for the normal work I will pul the chord.  I will 'tweak' and let you know how I get on.

ATCO B17 Sun, 30/10/2016

Today the neighbor borrowed the new toy and after charging the bat, taking off the starter, cleaning it and putting it back on - bingo  it fired up 1st time - perfect, thanks for all the help.  I guess the oil and the alignment needed a little attention.


I like this site. (just got to look for a thread on hunting now!)

wristpin Sun, 30/10/2016

Hunting. May be caused by an out of adjustment governor but far more likely to be caused by dirt or gum in the carburettor restricting the fuel flow and weakening the mixture. First off dismantle and thoroughly clean the carb.


ATCO B17 Mon, 31/10/2016


Thanks, I will try that and let you know how it goes. 

Do they do requests for spare parts on this site?  All I am looking for now is a grass box support (F016103780).  £65 for a new one but I will be happy with an old one to referb.  Thanks again.


Note - just found the add part so asked there.

ATCO B17 Sat, 12/11/2016

The hunting got worse and it wont start after I used it on a neighbors lawn, I think the carb must be very dirty so will put it into my local shop as taking the carb off is probably a step to far for me!

Ironically, the e-start works perfectly now and is the only reason I can tell it wont start and it turns over for a long time without firing!!  I will win.


On second thoughts, how can I identify the carburetor that will replace the one I have, I think I could change the whole thing and that will probably be more satisfying than getting it fixed by someone else.  Looking on the internet there seem to be a lot of Tecumseh carbs at reasonable costs so shouldn't be that hard to source.  It is old so probably due a change?

wristpin Sat, 12/11/2016

If your carb' was really old it would be easier to clean. Your issue is that it was made to comply with the emission regulations of the 2000s and then along came ethanol adulterated fuels with shorter shelf life and the propensity to gum up the small calibrated passages of an emission compliant carb'. A session in an ultrasonic cleaning tank would probably solve your problem and the work involved in removing and replacing it is no more than that needed to fit another carb' that may or may not be correct for your engine.

If you are intent on fitting a new carb' it needs to be the correct specification for your engine, not just one that looks "about the same"; so start with all the identification numbers on yours.


ATCO B17 Sun, 13/11/2016

Perfect thanks, that all makes sense.  I think my Father in Law has an ultra sonic bath so I will ask him.  I presume I don't have to remove any of the internal parts just the easily accessible jet/mixture screw to put it in a bath?

wristpin Sun, 13/11/2016

Take the float bowl off and remove any accessible internal jets etc. The fluid will only clean parts that it is in contact with. After u/s cleaning flush the carburettor with carb' cleaner or a water dispersing spray before reassembling.

ATCO B17 Sat, 19/11/2016

OK, so progress - I think.  Ultrasound awesome and carb cleaned up perfectly.  back on machine as suggested and it ran (with electric start immediately!!!)  after a short period, when I asked it to do work, it started hunting a lot, more than before.  It will now pull and start on high throttle but not on low and the throttle arm is going through full deflection during the hunting.  It will not sustain level running at any revs.  I can only see 1 screw on the carb, I think this must be the mixture (?) if I try to open it, the engine tries to cut so it is fully home; choke kills it as well so I start it with no choke.  It seems from other posts that the mixture should be open 1/2 to 1 turn but I can't if I want it to run, could this be part of the issue?

I am thinking - more ultrasound may be required and get a proper carb spray but I dried it well this time.

Thanks again for any ideas

wristpin Sat, 19/11/2016

An image of your carburettor will help together with any numbers etc. I think that you said that it's a Tecumseh carb' . Just to avoid any confusion does it actually have Tecumseh cast into it? Unfortunately  to achieve the required emission levels modern carburettors have some very fine drillings etc that can be a pig to clean . Was the u/s session in a heated tank and with a suitable detergent? I normally run my tank at around 50 degrees and for 30 minutes , stopping and turning the carb' to a new position half way through.


ATCO B17 Sat, 19/11/2016

Wristpin, I think you are correct that it just hasn't fully cleaned, the start up initially was so good that it has to be an improvement but not quite perfect.  I will do the ultrasound again but will also use a carb cleaner 1st..  I have no heating so will use warm water and turn it a few times - I will let you know and add some pictures of the carb to be sure.

ATCO B17 Sat, 19/11/2016

I think I have a definitive answer - it is Tecumseh.  ser 5148 (K5R) Service number 640161.  Didn't get as far as the year, month, day but might try - this lawnmower game is addictive!!!


Tecumseh 5148 (K5R) carb 640161  Tecumseh 5148 (K5R) carb 640161

wristpin Sat, 19/11/2016

That circular thing above and to the left of the slow running screw is a Welch plug covering a little chamber feeding the slow running and progression jets. If you get an aerosol of carb cleaner with a thin  tube in the nozzle and with the carb dismantled and said tube in the right place you should be able to see cleaner coming out of all (probably 3) tiny holes in the Venturi. A bit of a fiddle  and you will need to manoeuvre the throttle butterfly to get good view. 

If you can't see anything coming out of those holes there is probably contamination in those passages and behind the Welch plug. If you carefully drill the plug and lever it out it makes cleaning easier. Most decent mower workshops, especially those that also repair chainsaws, will have a box of assorted Welch plugs but, if needs must, repair the hole with epoxy and refit the plug with a smear of petrol proof sealant or even nail varnish ( colour optional) the around the rim . Or,as you mentioned in an earlier post, get a new carb from that auction site, but I'm not one to give up that easily!

ON EDIT just noticed that fuel filter in the second image. Is that a standard fitment ? If not,and it is of a type intended for use with a fuel pump rather than a gravity system it could be starving the engine of fuel.

ATCO B17 Sat, 26/11/2016

The air filter is the one for the carb but we do have progress - not done the Welch thing yet.  I got carb cleaner and stunk the garage out, then, ultra sounded it again.  Progress, it ran and quite well (still a bit of hunting so may have to drill/replace)  but I loosened the ?mixture? screw (other posts on here mentioned it?), below the plug and mother vibration did her bit.  The screw is now somewhere in my garden so have to find ine of those now before I can move on.

Small steps!!!!!

Ed, Ah fuel filter - I will check.  I have added a fuel cut off so I can remove the carb ad-nausium without loosing all my fuel now.

ATCO B17 Sat, 26/11/2016

This is harder than I thought.  I can't find the correct fuel filter (if mine is wrong) but as it runs better every time I clean it, I think the fuel is getting through.

I now can't find a carb with the same numbers and wouldn't know how to 'upgrade' as I presume there is a specific carb to replace the old one.  The internet is so close but I am just not sure which to get (I already have a 'spare' grass box holder rod through incorrect identification).

Is there a shop in the UK that can help/send stuff or a site that has the carb exploded model so I can see what I need.  Sorry to be a pain but it is such a good mower I really want to get it fixed and am so close.

wristpin Sat, 26/11/2016

As far as possible replacement cards go, a couple on fleabay 121740206167 and 152321095572 look as though they may be suitable. Interestingly they both have adjustable main jets which has to be a plus point as even though they may not be jetted precisely for your application, allows a bit of fiddle room.


ATCO B17 Sat, 26/11/2016

Wrist pin, Thanks and I have ordered the cheaper as the face of the carb is a different shape so may not be the answer but I hope it is the one, it looks very similar. 

I will let you know how it goes. 

wristpin Sat, 26/11/2016

Cross fingers! However so long as the mounting flange hole centres are correct it is often  possible to swap choke and throttle shafts to marry up with the governor linkages etc without the need for too much re-engineering.

ATCO B17 Tue, 29/11/2016

Sound good, I will try it, if only out of pure curiosity.  I have taken the bold step of sending my carb to Hailsham (Jon C) who is going to give it a good once over and replace the Welch plugs, clean the carb (properly) and add the errant screw.  I would like it to work as it is the original but if your suggestion works, I will have a spare - win win!!

ATCO B17 Sun, 19/02/2017

Update, Finally got the refurbed carb on and hey presto, it ran 1st time.  Much much better but a little hunt so have to have it on 1/2 choke.  It may be it needs a good run out to clear any gremlins but we are much further ahead now - there is light at the end of the tunnel.  I will pluck up the courage to look at the valves some time!!!  Thanks Jon C for the effort.

ATCO B17 Mon, 19/06/2017

Perfect so far and hopefully the last post (for this issue); used it a few times and it gets better with use.  The carb worked, no hunting and it cuts like a dream.  I have a new front roller (not sure I needed it but it looked shiny!!), new decals and a functioning starter - what could be better????

Thanks for all the advice and I know where to come if it goes wrong again!!