Qualcast Suffolk Punch 43s help

[build]

Hi,
Lawn mower Qualcast Suffolk Punch 43s

Problem:
Full choke on throttle full on
Pull to start,starts then have to switch from full choke to half choke back and forth befor it runs okay
Then runs all okay BUT have to keep it on 3 quarter throttle.
NEST PROBLEM

If after say 20 minutes I stop it to move to new lawn it will not start again until I leave it for 2 hrs.

I do not know how to set this mower up because do not know the settings for jets and also the thing at the back of carb, it has a little thumb screw with a spring and is connected to the engine with a lever.

The jets are 1 on front of carb set to 1 and a half turns out from full shut, the other one is inside petrol bowl "emulsion tube" I think ,which I do not know if should be full closed, I have set this one to the same as the above.

I think the carb is a "Dellorto carburettor"

Sorry for such a long text

Any help please

John

[build]

Does NO ONE know about this then?

[peter]

Truthful response is that this is a fairly small forum in terms of active members, with only a couple of machinery experts. There are other forums out there for garden machinery.

[Richard]

Last post in this section was mid March so I only check it a couple of times a week.

Anyway, the Dellorto was a very bad choice by Qualcast as they had a fixed main jet, it is the one underneath the middle of the float bowl, I see you have found the stuff Clive wrote about it and that you could get adjustable main jets to retro fit, this will cure it, as the jets fir up during Winter and require the needle opening up to get the same mixture as you were getting last Autumn. As the engine is run, the jet clears, so you have to screw it back in a bit, but it takes a few hours running. Cleaning the jet doesn't seem to work, so it is unscrew until it runs right at the start of the season, and gradually screw in, as it starts to run badly due to overfueling.

Second problem could be fuel related, blocked vent in the filler cap, blocked fuel filter, or sooting the plug due to the aforementioned mixture problems. However could be electrical. Briggs & Stratton engines have an annoying habit of doing this when the magneto coil is failing, so it may be the same problem, but try a new plug first.

[build]

Hi Richard
Thank you for getting back to me.

I'm a bit confused about two things

1......the "fixed main jet under the float"
Should this be screwed all the way in ? and never adjusted?

2......Clive wrote about it and that you could get adjustable main jets to retro fit
what is his all about ?

Thank yoou very much for your hekp so far.

[Geoff]

Perhaps Richard is referring to this old thread viewtopic.php?f=10&t=9814&p=101225&hilit=qualcast#p93949

[Richard]

The fixed main jet looks like a hexagonal brass bolt head and holds the float bowl in place as well as having the jet passageway through it, screw in until tight. The adjustable jet has a brass needle screwed into a similar brass bolt holding the bowl on. So you adjust the needle by screwing it out to give more fuel

[build]

The fixed main jet looks like a hexagonal brass bolt head and holds the float bowl in place as well as having the jet passageway through it, screw in until tight. The adjustable jet has a brass needle screwed into a similar brass bolt holding the bowl on. So you adjust the needle by screwing it out to give more fuel

Hi Richard,

I think I must have a differet carb to what you are talking about please see photo

I have NO jet in bottom of bowl as per red arrow. the jet is inside the bowl at the top which I have got un done to i and half turns
which i do not know if that is correct or not.

The other one that the red arrow is pointing too i screwed right in the 1 and half turns out
CONFUSEd

[Richard]

That is the fixed jet. As I wrote earlier it looks just like a brass bolt head but if you unscrew it you will find the jet passageway from the side, inside the float bowl, up the centre of the brass "bolt" and into the carb venturi. Just at the moment someone in China has got the idea of making replacement carbs with the adjustable jet. I assume E10 fuel has wrecked quite a few Dellotos over Winter but I am a little surprised bits for a 40 year old engine are easier to get now than when they were new. https://www.ebay.co.uk/itm/394004390031?hash=item5bbc7de08f:g:NiIAAOSweipiPuPo

[build]

That is the fixed jet. As I wrote earlier it looks just like a brass bolt head but if you unscrew it you will find the jet passageway from the side, inside the float bowl, up the centre of the brass "bolt" and into the carb venturi. Just at the moment someone in China has got the idea of making replacement carbs with the adjustable jet. I assume E10 fuel has wrecked quite a few Dellotos over Winter but I am a little surprised bits for a 40 year old engine are easier to get now than when they were new. https://www.ebay.co.uk/itm/394004390031?hash=item5bbc7de08f:g:NiIAAOSweipiPuPo

Oh that looks good then

So do I just take off the old Dellorto complete and replace with that one?

If so what about the bit of metal that connects from carb with the knob and spring to the bottom of the eng house?

Look on pic it is the spring to the left of the bottom red arrow
Thanks very much for your time so far

[Richard]

The plunger with spring under the float bowl is to drain fuel from the bowl. Water finds the lowest point and this provided an easy way to remove it. Those Chinese carbs may, or may not be an easy fit. I often find with "Chinese knock offs" they don't get them exactly right, and some alterations may be needed.

[build]

The plunger with spring under the float bowl is to drain fuel from the bowl. Water finds the lowest point and this provided an easy way to remove it. Those Chinese carbs may, or may not be an easy fit. I often find with "Chinese knock offs" they don't get them exactly right, and some alterations may be needed.

Hi Peter,

Sorry I have not explained my self to well.
It is not that one that I was asking about
I was the one that goes to the eng houseing
Would you disconect that and leave off
I do not know what that does anyway ha ha ha ha


Please see new pic
I have been to the site and had a look at it BUT it is most confuseing one time it says for a 43s and another time it says 40 also it says
diesel.

[Richard]

That is the governor linkage and must not be altered unless you know exactly what you are doing. the linkage goes via rods to a lever on top of the carb. If changing carbs, you unhook the rod from that top lever as you remove the carb, and hook the new carb onto the rod as you fit it. Some carbs have more than one hole in the lever, so take note which hole the rod is in.

A few weeks back I came across a website selling adjustable jets, this is an easier fit, as you simply remove the old main jet under the float bowl and fit the new one with the needle up its centre. Can't find the website now though.

[build]

That is the governor linkage and must not be altered unless you know exactly what you are doing. the linkage goes via rods to a lever on top of the carb. If changing carbs, you unhook the rod from that top lever as you remove the carb, and hook the new carb onto the rod as you fit it. Some carbs have more than one hole in the lever, so take note which hole the rod is in.

A few weeks back I came across a website selling adjustable jets, this is an easier fit, as you simply remove the old main jet under the float bowl and fit the new one with the needle up its centre. Can't find the website now though.

SORRY RICHARD... called you PETER must be old age.

Oh i see what you mean now about the governor.
I presume that controls the rev of the mower under load.
Mine would not rev up if it found a long bit of grass and had to give it more rev with the throttlr control.
So I did turn the knob down a bit and that made it rev up a bit more.
Hope i did correct or I messed it all up ha ha ha ha
Any way thank you for all the info that you have given me and wait to see if you can fined that web page.
I will do a search to see if I can find any where.
Kind Regards
John

[build]

That is the governor linkage and must not be altered unless you know exactly what you are doing. the linkage goes via rods to a lever on top of the carb. If changing carbs, you unhook the rod from that top lever as you remove the carb, and hook the new carb onto the rod as you fit it. Some carbs have more than one hole in the lever, so take note which hole the rod is in.

A few weeks back I came across a website selling adjustable jets, this is an easier fit, as you simply remove the old main jet under the float bowl and fit the new one with the needle up its centre. Can't find the website now though.

I have just come across this old post
just to recap I did send for the new carb BUT when it came after 9 weeks it was the wrong one so I just packed the mower away in the shed and did not touch itr again. I bought a hove one did not like it and i have found my old 43 again
Just was thinking did you find that link for the adjustable jets,?

I know this is a long shot after all this time but I realy do want my 43 back running
Kind REgards