OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers CARBY BUGGS

Gday Fellers
Names Red Im new to posting but been pokin about here for some time now
Fab site Im very glad for its being yeah
Ive an old HK30 H4-4A It's on a SCOTT BONNAR greens mower.
The poor old thing was parked under a tree for Christ knows how long.
Filthy and with air cleaner, no muffler, carby full of crud, had to dig the bowl out.
So the fins were jammed packed with grass dust dirt and oil
spent three hours alone cleaning the carby up.

Surprisingly the bore was nice; the valves neat as and the thing turns over lovely
I stripped every thing off it n scrubbed it up nice,
lapped the valves, put her all back together with out paint as I wanted to see how she ran before I went to the trouble.

Well it fired first pull.... youuu lil bewdy
but wouldn't rev out
Ive re-cleaned the carby and checked the governor and everything is good o.

I think the bottom of the shaft that the main jet screws into to retain the bowl has corroded some were the square notch is normally to about twice its size.... I put a plastic sleeve around it and it helped.
The thing will run and free rev as long as I hold my finger over the intake of the air filter mount closing the hole by 3/4's
It will idle nice and free rev nicely although I feel that just a little muted as the timing wasn't absolutely spot on as I did it bushy style

I'm also wishing to see how the internal governor gears are aligned. I've searched this site through many, many threads and haven't found a great deal about them or pictorials on the innards on governors for H30s.
Maybe someone could point me in the right direction.

I did take the carby off another motor going well and it worked a treat on the motor I'm currently working on...
the only thing I didn't do to the carby was remove the welch plug and do the tip cleaner thing there...

In lieu of the fact that mostly all seems reasonably well, could anyone suggest other things for me to try with my carby?

Also would some one in the know mind if I was to ring them n talk in person? My number 0408 348 232 text or ring and I will ring you back to save you the money as I've a business number.
I'm chuffed with these little motors to cop sooo much neglect and still get up and have a go with little more that a clean up is pretty bloody good ay!
Also Id like to put a full kit through the carby and put new stickers on the new paint
Ive two of these mowers Im doing up both seem quiet well n healthy for their age n state of neglect but Im thinking of rings n barings in both as I may as well do it one n do it well
can someone suggest a place in Aus to buy such
Thank you in advance for any help
Great site yeah
Cheers, The Redfella

G'day Red,
I know there is a manuals section on this site.
That may help you.

I have never touched one of these, but it sounds like you need to source another carby. If you have cleaned the carby best you can.

If you restrict your intake it runs better?
Sounds to me like a fuel restriction.

Gday Mark
As I said the only thing I didnt do to the carby was pull the welsh plug and clean under there
Also Im still not sure about the missing bit where the main jet screws in
Its where the square knotch is cut into the main jets housing Ill tinker with this and new carby kit some more before I trash the carby
Ive painted it up other day n she came up noyce maaaate yeah
Once Ive sorted the fuel I will start on the mower n restore that

Thankyou Mate for your reply

As Mark said, if it runs better when you choke it, it is running lean. There are essentially three things that could cause it to run lean at speed but not at idle:
1. Restricted fuel supply. I suggest you remove the float bowl, put a cup or tin under the carburetor, turn on the fuel, and see how fast it runs out of the carburetor into the cup. If it doesn't run full-flow, you have crud in the bottom of the tank, the filter, or the fuel tap (since you've already cleaned the carburetor).
2. Restricted main jet or carburetor body drillings. You said you've cleaned the jet. You need to be able to squirt carburetor cleaner through all the carburetor body drillings. I suggest you don't remove the Welch plug until you've checked everything else, though (both items 1 and 3).
3. Intake pipe leak. A leak in the intake pipe or the gasket where it mounts to the carburetor or cylinder can cause lean mixture. In most cases that kind of leak causes hard starting and poor idle though, to an even greater extent than lean running at high speed.

All this is based on your statement that it runs properly when you choke it. If it seems to run a bit better but still not properly, that would be a different situation and you would need to check your ignition timing, which is quite a complex procedure with that engine.

Hey Grump
Mate thankyou for your advice
I,ll strip n recheck the carby again

Do you think that the squar slot in suction tube where main jet screws into being about twice the oridginal size could be a problem
should there be a gap between the end or that tube and the bowel when the main jet nut is tightend
I wonder if my eforts to repair the damage to the tube with the plastic sleave has resticted fuel intake to main
ill try to check that as well
the old thing came up nice with paint black motor red coweling n fittings bare alloy carb

Red, I do not think you can expect a carburetor in that condition to work even as well as yours does. There are normally drillings coming into the side of the passage the main jet screws into. I can't visualise what your plastic sleeve has done to these, but in my opinion it is not worth thinking about anyway. You need a carburetor that has all of the parts, in original condition. From what you have said your carburetor's only usefulness would be as a source of spare parts.

I am not saying that your cobbled carburetor cannot be made to work, by analysing the status of each fuel and air passage in the carburetor, determining whether your cobbling has affected each of them, then designing a form of cobbling that will allow the carburetor to work after a fashion, for a while. However Outdoorking supports good workshop practice, and this does not include holding damaged carburetors together with pieces of plastic tubing in crucial areas.

Gday Grump
Interesting choise of word cobbling

Ill get photo of said cobbling n try post it

I understand where your comming from with quallity control n your attitude to service provided

Ive had to do quite some cobbling over the years to get by the practice has served me well on many occasion
Thank you for the insite

Could you tell me if and where , as well as what one may expect to pay for a replacement carb
Cheeres Mate yeah

Hey Red
I almost got to the stage of buying. Didn't look to far past online, but stack of places in the states sell them online with reasonable postage prices.

Gday Barry
Mate thankyou for yuor reply
Ive spent the arvo pokin about the net n see that there are good places about to get bit n peaces
I thought about what the Grump had said n went to have another crack at the carby
took some phots of what I done by way of cobbling just waiting for my doughter to show me how to load them to computer from camera as this is new , the old one I had a handle on also she has made herself the moderator

anyhow I tinkered with the carb and got the motor running nicely not quite as slow an idel as Id like but good O and Ive no idea what Ive set top speed to but its sounds ok to cut grass to and Isnt anywere newr three quarter throtle n sits on the governor nicely
I will reset that later when Ive refurbished the mower n refit the motor
BUT since Ive not put anything new into the carby Im very optermistic as the the outcome once I do so far not to bad an investment for something I was told would never run again and only cost me a dozen stubbies
Its given me something to do on cold wet days down here when I cant work on horses
Im a Farrier for my living
anyway Ill chase the super brat up to help me post these phots later
good O Mate thanks again yeah

Cobbling can be fun Red, but a plastic tube inside a carburetor isn't likely to last very long (the few plastics that are petrol resistant tend to be expensive), so you don't have much chance of it working for long. However if it stops, or begins to run badly, you should be able to go straight to the source of the problem.

Getting bits for old mowers requires either a lot of luck, or being plugged into a network. A number of Outdoorking members are often able to help each other with bits, if you post something in the Wanted section.

Gday Grump
Mate thankyou for your post
I thought about your advise n removed the plastic sleave which went aroind the outside of the suction tube and was only about 15 mil long
It run n idles n revs nice but could be better
Thanks Mate yeah

Red, I've been known to build up parts with solder, or even epoxy, in some circumstances and had it work. However epoxy only lasts approximately one year immersed in petrol, and most plastics last less than that. Solder lasts well but it's hard to cut a thread on it. Silver solder is quite good, though.

Good morning grump olson
Hows the weather down here the last few days
Up date on the carby
I tickered a tad more with float level settings rechecked the venturies sealed the welch plug noticed air bubbles when blowing out carby with air

so eventually went back with the sleve on the suction stem main get
cut a knotch in where the one would be had it not rotted out put her back togeather and she farts like a btumby you lill bewdy idels n runs nicely and revs nice

I did try to solder it grumpy but I couldnt get ti to stick
mine you I use heating with a lill pencil butain torch and electrical solder
I recon it could be done by someone cleverrerer than me ha he you know a cretin :o)

they say THEY W.T.F. are the ? there is a very good epoxy about nowa days the would stand up just gotta find that
But in any case it up n running good O for now
Ive start on the bace completely stripped down just got to clean n sand n paint
If I can ever get my girl to set this thing to take my photos I give you a squiz of the damage ive done ha ha
I do thank you for your help thus far and hope you wont mind me anoying you further as I attack the mowers working bitz
I copped a fair ol floggin workin on horses yesty n my backs actin up some so if its lousey wheather saturday I will tinker in the shed instead of playing a game of swear FORE!!
thanks again GUYS yeah

If solder wasn't sticking to a brass jet, either you didn't get it hot enough or you didn't get it clean enough. You need a good flux to clean it while it's hot - cleaning it when it's cool doesn't help because it will oxidise while you are heating it.

It sounds as if you found where your plastic sleeve was obstructing one of the passages of the carburetor, and cut it away to fix that problem. The remaining problem now is that the soft plastic sleeve probably won't last any time at all, submerged in petrol.

At least you are making progress, even if it is almost certainly temporary progress.

Hey Grumpy
Yeah were pokin along steady bud ay ;o))
Im not trying to solder the brass jet olson its the alloy that the jet screws into yeah
Gee I wish my doughter would set things up so I can get photos from my canera to the computer
as soon as I can Ill show you what Im up ta the sleeve goes around the outside of the soction snorkle please excuse my not knowing the correct name of the part in question
you have to try n realise your dealing with a complete pleb Grumpy mate yeah ha ha
or maybe you did long ago ha ha
I have a chuckle at your distain at me useing plastic I can visualise you sitting there shaking your head
There is a neat vid on youtube of a chap useing a butain torch n a special rod that he used to weld coke cans n heads n carbys n feul tanks , fab stuff , if I can come up with such I may give it a try
your a wealth of knowlage Grump olson n Im greatfull for your being
Tar mate yeah

So it is the carburetor body you have been trying to solder, not the brass jet. The carburetor body is a casting of either aluminium or zinc, with aluminium being more likely. You cannot solder aluminium. I'm aware of the stunt with the alleged aluminium solder and the guy with the butane torch. I'm told that stuff is more than 80% zinc, alloyed with a small percentage of aluminium, and sometimes you can get it to bond a bit to extremely thin aluminium sheet (I've seen a guy demonstrate it at a flea market stall). I've read reports from people who claim to have succeeded in using it to repair small defects in aluminium castings, but most of the experts dispute that it has actually happened. So, it may be that you could use that stuff more or less successfully. Of course the small package that they sell would cost over $20 from memory, and a healthy second hand carburetor should cost less than that.

As long as you are having fun with this, I guess you aren't doing any harm, but in the end I think the solution is to get a usable carburetor from a junked engine.

Oh right O I thought Id be up for heaps mate yeah
but the one asks how hard are they to get /

TIS A GOOD MAN YARE GRUMP

Why not post in the Wanted section here at Outdoorking, Red? People often find what they want that way, and it doesn't cost anything.

The add could read as such
WANTED THE WINNING NUMBERS FOR NEXT WEEKS LOTTO

CALL THE REDFELLA and tell no on ealse ay

This the old girl tidied up some