OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers SB 45 Identification please

Thanks Gadge, my bad..I was under the impression that each pic was not to be more than 4mb in size...I now know better.
Cheers
Gazza

No worries OF54,
Correct, but there's also a 15 pic per post display limit, which isn't mentioned in the 'how to' or help for direct uploads.

Great pics BTW; I'll let our in-house SB aficionado comment on the condition of the bits. The chassis rails under the engine look to be crack-free, and that's the chief achilles heel of the SB45 twin-rail design.

The main limitation with Kirby-made engines these days is very limited parts availability.
Kirby exited small engine manufacture in the 1970's, and Tecumseh Engines closed down in 2008. It can also be difficult to cross-reference Kirby and Tecumseh part numbers.

Hi OF,

My first port of call would be the engine and to see if it was worthwhile salvaging or simply swapping it out for a new power plant which isn't that expensive now a days.

Is there a good amount of compression, pull rope starter and see how much resistance there is.
Secondly how much sideways free play is there in the butterfly shaft on the carby. That's the one with the plate on top with a rod connecting it to the governor lever. If there is a fair amount of wiggle in it then that shaft is a scrapper and new ones are no longer available. It's easier to buy a replacement carby off eBay and replace the whole unit opposed to messing around with an old worn out unit that will leak air and give the engine a hunting effect while it's running.

Apart from that it's a full strip down for this particular machine as it's been sitting in a corrosive environment and just looking at the reel, rear roller and the engine tells me a fair amount of work will be required to bring this one back to it's former glory. That being said it's all just time and effort and you'll be surprised how well it will shine again.

Cheers,
BB.

Thanks BB, your enlightening opinion is very valued indeed.

Compression...yep...there is what feels like a fair bit...it blows my hard pressed thumb off the spark plug hole in no uncertain terms.

As for the carby...it just so happens I have just removed it and gave it a bit of a wash. The butterfly shaft you speak of is actually frozen and short of me using a pair of pliers or the like..'she ain't moving"

I have some pics of the carby for anyone to identify and if one the same isn't available or this one is unable to be re-kitted and overhauled...what is the best option ( and why )





of an eBay or Amazon one to replace it?

Can I assume that this is the original carby?...and if so...what was the correct part number so I can obtain a viable replacement?

Regards

Gazza

I think I may have answered at least one of my questions.

The flat 'tab' under the mixture and idle screws had some flakey paint on it...so I carefully removed the paint with a sharp pocket knife..and "Wallah!!!...the stamped number "302' appeared.

I used this number to cross reference on the following website and I came up with a Tecumseh Pt No of "631471"

http://www.tecumsehcarburetorguide.com/carburetor-identification/

Here's hoping I got it right

Regards

Gazza

Hi gazza,

Well I wouldn't worry too much about part numbers on that carby as you're not going to get a direct replacement number equivalent. You'll source one from eBay for around $30, but before you go down that road I would work on freeing up that butterfly and assessing the original because if that butterfly becomes fully serviceable then you'll be able to use that one.

Just keep soaking it with "Penetrene" etc. at both top and bottom friction areas, but do not force it via the flat plate on top as you'll bugger up the solid connectivity between the brass shaft and the plate with it becoming loose. Just be gentle with it.

If you have some carby cleaner in a spray can feel free to use that to.

Cheers,
BB.

Another thing that usually works well on gummed up carbies, is to soak it in acetone.
Needs to be in a closed container [glass or metal] so it doesn't evaporate too fast, though. And it will take all the paint off.

Hey BB, yup...you're dead right about not finding a similar carby...every part number under the sun and nothing even like it anywhere.
I'll take the Acetone path and really let it do it's stuff...I'll remove anything rubber or plastic before doing it though. It's a pity that "Carbusol" is now banned...I remember dunking an absolutely filthy Rochester 4 BBL in it many moons ago...dammm...I thought someone was playing a trick on me..it came out like brand spankers.

For authenticity I hope when I overhaul it will be fine.

As for cleaning out tiny passages and holes etc...I have managed to score a heap of tiny Dental files that are used to do root canals and things...very hand.

"Right said Fred"...here I go with another little missive...please do not adjust your screens or channels...normal transmission will return shortly.

I took Gadge's Acetone idea and the carby base minus the bowl now looks like brand new, the paint is sitting forlornly at the bottom of the large glass Pickle jar and the alloy carby body is fully nude and shining.

A small droplet of WD-40 on the butterfly shaft and with a slight grip via a pair of pointy nose pliers with which I gripped the shaft beneath the Governer Plate...it freed up and has nary a sign of any free play whatsoever. So..from this assessment it looks like I'll be able to rebuild this carby and keep the restoration authentic.

Question uno numero...how does one remove the brass Needle and Seat body?...it doesn't seem to have a flat tip scew driver slots in it which is pretty much the go for most carburator things these days.

Question Zwei... which kit do I procure via unknown means which will have the correct replacement parts I need? The Brass Float isn't damaged nor leaking that I can see and I will try to re-use it.

Are there any other tricks to removing any other internal parts that need to be replaced or cleaned as well.?

Cheers again

Gazza

Ok...next question for those in the know...where I have circled the head Bolt in the pic below, underneath I found a broken piece of what I'm thinking was 'spring' steel that was used as an engine stop device by shorting out the sparking plug. Since the plug cable is bereft of the usual rubber protective connecting cap...I figured that this maybe the reason why.

Any clues

Cheers

Gazza
(Have I bored you all to tears yet?)

Yup, you have it. Here's a pic of one, from a past thread:



It doesn't need to be that good a spring steel - a piece of steel pallet strapping would work.

On the carby needle seat question, if it doesn't have an external hex or driver slots, it's pressed in. That means it can't be removed without wrecking it, as far as further use goes. What does the conical tip of the needle look like, condition-wise?

Gadge my man...where would I be without you?...honestly...you are a fountain of knowledge that keeps on flowing.

To answer your question...yes...it looks like it is pressed in and unfortunately there is a concentric wear ring on the Needle Valve tip.

That being said...and to your knowledge...has a pressed in Needle Valve Seat ever been 'drilled out and a new one pressed back in?

Oh...I will now say that you must've read my mind...my next question was..why is there a plastic hose pointing upwards from the same place the Main Fuel Line enters the carby..taadaa...a Primer bulb connection of course.
Thank you Gadge.

All...and that includes newbies like me,

I have been here a matter of days and the info and 'camaraderie' (Define camaraderie: a feeling of good friendship among the people in a group) has stunned me.
To be brutally honest..this is as close to a "Men's Shed" as you will find.
To say I am humbled by the responses and by the meaningful honesty of those here...is an understatement.

At long last I feel as though the grease under my fingernails and the smile on my face as I see the replies and freely offered help, confirms to me that men of all walks and ages are a kindred beast that needs to use his hands and mind to 'produce' not only the world where his family can live and aspire...but a place where he as himself can mix and join in the fellowship of his brothers.

Behold all...an online place of respite from the hardships of life as we know it.

Gazza

Oh yes...can someone explain to me why these Tecumseh engines needs 2 drain plugs?

Got me buggered.

Cheers
Gazza

Hi OF,

Well some did and some didn't. This was primarily as an option so that regardless of what the engine was fitted to it could be more easily emptied. Quite a few Briggs engines have this and if I'm correct all the latest sloper engines that Briggs make have this option fitted as standard. In regards to the oil entry facility if you look at the earlier engines they were all cast with the ability to have the fill point on either side, but generally they were just machined out on one standard side but some are getting it machines on both sides.

As far as those primer bulbs on the Kirby engines are concerned they are a bit of a waste of time as Kirby's usually start first or second pull once the petrol tap is placed in the open position.

Mens Shed............mmmmmmmmmmm. I think we're way past making wooden rockin' horses here and there's far more knowledge here than a mens shed that's for sure.

Gadge, sorry about the delay in answering 45 stuff, but I've been in hospitals with my 7 year old daughter that's broken her ankle and now has it in plaster. Crutches and 7 year olds don't play well together I might add.


Cheers,
BB.

Just a quick one while I'm still here.

I've noticed that the "Scott Bonnar" fuel tank stickers (as portrayed in that stock photo a few posts above) that are made by Grant are somewhat incorrect and it does annoy me a bit that they are printed on orange stock when the originals were printed onto clear that way the sticker itself wasn't to be seen, but rather just the white and black lettering is seen on whatever paint is used.

I'm really surprised that Grant has never changed this as the technology is most certainly there to do it now rather cheaply.

Cheers,
BB.