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Collection, Preservation and Display of Old Lawn Mowers

Updated: Atco Balmoral 20SE Slow running problem

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Greetings 

I wonder if you can help me diagnose a problem with my Balmoral, model number F016309942 . I have had this since new, bought 2003.  Its generally been fine, only had light use as I have others to use  ( had Mountfields, Flymo's and recently got a Hayter) .  It starts OK on the pull, but when warm the tickover is like this (YouTube video).  When I open the throttle and start cutting it runs better , but it used to be slow, steady beat that would just keep going. but the slow running has got worse over the last couple of years.  Now, unless I open the throttle a bit, it will die. I have taken the carb off, dismantled it and given it a clean , but to no effect.  I dont' believe I have anything blocking the main running jet but I wondered if there was another place where crap could build.  I am not sure what make of engine I have, and therefore what make of carb , but its stamped as per the picture below.  It says 5148, which leads me to believe its a Tecumseh , but I dont' know how to identify the make of engine - perhaps one of you will know, by the age of the mower.

 

I am looking for some assistance identifying the carb and/or diagnosing the problem.

Huge thanks in advance

https://youtu.be/fQnH-Imp634

Added some extra pics at the request of wristpin - hopefully now the vid above is public and viewable. 

 

Carb Stamp 1

Carb Stamp 2

Forums

wristpin Sun, 03/05/2020

The vid says that it’s private. An image of the whole engine will be useful for identification.

MalcoPop Mon, 04/05/2020

Bear with - I'll get back to you on the YouTube vid...never done an upload before ....and get some pics of the whole engine.

Thanks for your patience.

 

 

MalcoPop Sun, 10/05/2020

I've updated the top-level post - please tell me if you can see the video now. 

Thanks

Malcolm

wristpin Mon, 11/05/2020

 What you have there, is “ hunting” and the culprit will be a restriction in the slow running system. As an aside, all adjustments must be made with the air cleaner in place.

Strip all the jets and adjusters out from the carb body and use the thin tube on an aerosol of carb cleaner to blast through every orifice. If you look into the wall of the Venturi just where the butterfly closes onto it, you should see two or three minute holes . If you get you blasting of cleaner right you should see cleaner issuing from said holes. Those holes are connected to a gallery in the slow running system . That gallery is often accessible and closed by, a welch plug in the carb body. To clean a badly contaminated carb it may be necessary to remove the welch plug.

Looking at your earlier image of the carb with the air cleaner in place it looks as though it may have a slow running adjuster covered with a blanking plug to discourage fiddling. If that is the case, remove the plug and see whether turning that adjuster either way will smooth out the hunting. 

If you have, or know anyone with an ultrasonic cleaner , strip the carb and give it a hot half hour session.

 

MalcoPop Mon, 11/05/2020

Thanks for the reply.  I too was thinking that it was something to do with the slow running, but with the carb stripped down, I couldn't see anywhere where there might be jets to adjust.  Now I have a better idea what I am looking for, 

I have an ultrasonic cleaner, so I'll give it a blast in there.

What is a welch plug ? 

Thanks

Malcolm

wristpin Mon, 11/05/2020

Welch plug. Good question . A little slightly domed disc of metal used to seal a hole used to aid machining in the  manufacturing process.  If you look on the opposite side of the carb from that shown in your initial image you may see one.

 

Edda Sat, 16/05/2020

I have the same Atco model as yours albeit the 14 inch. I got so fed up of the engine for that year model that I replaced it with a Honda Engine. Looking back I think I played with it for ages trying to get it to run correctly and in the end it just would not start, hence the replacement Honda Engine.

MalcoPop Thu, 28/05/2020

Success !!!!  Huge thanks for the pointers - In fact, it was the slow running jet, hidden behind a plastic plug that I didn't even know came off.  The jet was well and truly gunged up. A poke with a fine guitar string and a shot of Wynn's carb cleaner, and she runs just like the day she was born.  Next fix - get the electric start working again.  Think I need to start with a new battery, mine is still the original .  I'll check the system works by giving it a belt from a car battery and see if it cranks up :-)

Regards

Malc

MalcoPop Thu, 28/05/2020

Edda - Interesting ... was it a straight swap ?  ie no messing around, getting stuff to fit that doesn't really want to.