Hia all
I'm new to this site so hello to one and all.
I have inherited a lawnmower Qualcast 43s with a Dellorto FHC 2013A carb that has the retro fitted adjustable main jet. (as mentioned by Clive in his Atco B20 solution dated 25 June 2009)
It would appear I have a similar problem in that I think the carb settings may
have been tinkered with in the past.
As it will only run on full choke, do you think I am in the right area?
So any help with setting up the dellorto carb from scratch will be very appreciated.
In Clive's post above he mentioned some additional information he would PM (?) to the reader.
Would you ask Clive if he thinks this additional information would help me to resolve my problem ?
If you require any additional information do not hesitate to contact me.
Many thanks in anticipation.
Stan

Stan, welcome to the forum, sorry your first question has not been answered but I am not very clever with mechanical things, perhaps one of the guys here will be able to answer your queery.

Hello Stan,
I have just checked some old Qualcast paperwork and it was 26 years ago that the mower world was battling with troublesome Dellorto/Qualcast/Atco.

I have sent a private message (pm) regarding your question....apologies for my slow reply...I was waiting for a few quiet minutes on Saturday morning to get it sorted.

Clive.

Clive,
Many thanks for the information you were kind enough to send. First I must apologize for my tardy response I have just got back from holiday, so on Monday, armed with your settings I will attempt to tame the beast.
I promise to let you know how I go on, warts and all.
Thanks again
Stan

Finally I have a fully working mower, but it turned out to be a bit of a saga.
First thing Monday the mower refused to start at all.
Found i had a spark so assumed it must be fuel problem, so stripped the carb and found it was full of black bits.
So off to halfroids for some carb cleaner, and ten minutes later had the mower running, albeit still on full choke.
But the mower ground to a halt shortly after.
Same symptoms as before, so stripped carb again and surprise surprise, was full of black bits again.
Turned out to be the sponge air filter disintegrating.
So off to mower shop for new filter, another blast or three of carb cleaner and the recalcitrant mower burst into life once more,,,,,,,,,,, but would still only run on full choke.
Time to enlist the help of 'Clive" the mower guru. True to his word he provided me with a
"Service Bulletin" which even this limited mechanically minded OAP could follow, so following the setting up routine, the main jet was optimised (at 1 3/4 turns out) The slow running and tickover speed screws set as per instructions and the mower was ticking over like a dream, and more importantly, with no choke.......hurrah.

Once again, Clive, many thanks for your assistance, you are a gentleman and a treasure.

Stan Mutch

Hello Clive
You seem to have all the answers ! I have recently been given a 43S (L80102) and have similar problems, I also have to have the choke on or it cuts out, and also it will not tick over, it has to have a lot of revs to keep going which in turn brings in the cutting blade. It is quite old, I guess about early 80's, and still cuts quite well, and I don't mind having a tinker, so would love to bring it back to it's best, I plan on a full strip down and paint this coming winter, so any info you have on adjustments would be much appriciated.
I have found the same model on ebay which I have as clarification, http://www.ebay.co.uk/itm/QUALCAST-SUFF ... 2a12a476c3

Cheers

Mike

PS What would be the best meathod of sharpening bottom blade and cylinder, I have access to a lathe and workshop facilities, for when i strip down mower in the winter.

Hi, I think I may be having the same trouble. It does only run at full choke if u turn it to half or off it jus cuts out. I was given my mower also so I to am not sure if the settings on the carb are correct and was wondering if someone could post the setup please. I've ordered an air filter and I'm gona pick some carb cleaner up on my way home from work but would like to know I've set it right.

I've also got a question about the drive and cutter on tick over the blade always spins and intermittently the drive goes and jumps forward, I'm fairly sure the drive isn't right but at a guess I would say the blade should spin?

Any help tips or advise would be greatly appreciated!

Mike F.

Hello Mike,
With the engine set to a slow steady tickover the blades should not spin. Most of these mowers had a centrifugal clutch and the blades should only come into drive as the engine revs are increased.

It could be that the blades are not set on cut correctly...the cylinder is adjusted to be just lightly touching the fixed bottom blade. The best analogy is like a pair of scissors. If too slack scissors won't cut, if too tight they are hard to operate..if blades are lightly touching together they are fine.

If the cylinder is adjusted down and the chain is not checked then the chain may become tight and need adjustment. A tight chain can pull the top clutch shaft out of line and cause a drag of the clutch spinning the blades. Engines need to be correctly aligned to clutch too...sometimes the engine can have shims under one corner to level things.

A clutch fault could also be the culprit. **Never ever run the engine with clutch outside of its drum...the clutch shoes would open and could break away causing serious injury**

Sometimes the clutch backplate on crankshaft can come loose and move. due to a loose grub screw

The drive belt for forward motion has adjustment on the cable and also by shims between the cutting cylinder split pulley halves. It is also important to have the pressed steel belt guide located correctly to keep belt in shape, but clear of the front pulley when out of drive...this guide may require adjustment relative to the cutting cylinder position as it gets lower with use and subsequent corrective adjustment.

The Dellorto carb' type was problematical even when new. The engines take a long time to fully warm often needing half choke before fully running with choke open. Often the central main jet tube within the carb gets blocked and needs removal for cleaning...strands of grass and fuel gum can often be the culprit.

If you have doubts as to you ability to safely perform repair and adjustment then entrust the task to a local service agent all should be familiar with this engine and mower.

Clive.

It sounds like i have some work to be getting on with then!

Im at work until sunday so im going to set aside monday morning to go through all of your tips, so with regards to the drive/cutter just to confirm at slow revs neither should run, high revs the blade should run and only when your pull the lever then the drive should run also.

Thanks again

Mike F.

At a slow steady tickover the blades should be stationary....subject to all being in good order. Dellorto carb versions of this mower could sometimes suffer from a lumpy tickover in order to get a good pick up to rev and to give best running at mowing revs....

As the revs increase the centrifugal clutch shoes expand into their drum thus transmitting drive via the left hand side chain drive to turn the cutting cylinder.

From the right hand end of the cutting cylinder there is a v belt drive that takes drive back to the rear roller. The belt is tensioned to give forward drive by pulling the handlebar clutch lever...and released to stop.

Later 43S may have had belt drive on both sides...but I refer above to the mid/late 1980s 43S with Dellorto carb' and derived from the C.1969 chassis of the old faithful Suffolk Super Colt.

Clive.