Qualcast 43S fast running

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Sissonsdarren
KG Regular
Posts: 2
Joined: Sun Aug 18, 2019 9:44 am

Hi there,

I picked up a qualcast 43s as a non-runner and stripped the carb down and cleaned the main jet and managed to get it starting, after trying to cut the lawn it’s seems to hunt.

I have tried to alter the idle, governer and all sorts of things but it either only runs on full choke, won’t run on slow speed and when using very little movement on the pull handle it near pulls me up and over the garden fence!

Can someone please help with an initial set up guide and how to adjust to get a smooth steady idle and run on slow speed.

Many thanks!
Westi
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Hang in there Sissonsdarren! The clever guys will get back to you as soon as they trudge home from their patch! Welcome to the forum!
Westi
Richard
KG Regular
Posts: 71
Joined: Mon May 08, 2006 8:37 pm
Location: Lancaster

If the carburettor is a DelOrto this is standard for a Qualcast engine which has been laid up for a while. Half choke for the first half hour of running is common, but they do get to running right eventually if you keep using them. Qualcast did sell adjustable main jets, which is the cure, but nobody seems to now know the DelOrto part number. If your machine still has a fixed main jet (no needle and spring under the float bowl) just use the machine on half choke until it does run right. You may have to set the governor to get the running speed right, but I would advise waiting until it will tick over without choke before setting the governor.
Sissonsdarren
KG Regular
Posts: 2
Joined: Sun Aug 18, 2019 9:44 am

Hi Richard

Many thanks for the reply! It does indeed have the spring drain under the float.
Noted about the running for half hour before running right but once it’s going right is the a way to set them up? I picked it up second hand and suspect the previous owner tried playing with the various adjusting screws?

I.e what does the screw on the carb do ( is this the idle?) and what are the high and low level springs on the governer?

Just want to ensure fully underside how to keep one of these!
Richard
KG Regular
Posts: 71
Joined: Mon May 08, 2006 8:37 pm
Location: Lancaster

Sorry for not getting back, I hadn't noticed you had added to the thread. The spring and needle I referred to goes through the middle of the brass bolt holding the float bowl on. If it hasn't got one, the main jet is fixed. If it is a DelOrto there will be a idle mixture screw near the top of the carb and the slow running screw on the side of the throttle lever on top of the carb. I think the later Tecumseh engine's carbs are similar, though I believe they do have the adjustable main jet needle under the float bowl as standard.
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