OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Tecumseh / Kirby Engines Kirby Miss-firing - Gets worse the hotter it gets?

Hi all looking for some expert advice on a kirby H4 2.5hp on a scott bonnar 45 It starts and runs ok for a short time, then starts to miss fire and hunting slowly gets worse ?? I was thinking of condenser or coil being the problem. As I have changed the spark plug and cleaned the fuel tank and carb out, lots of dirt in both, but still have the problem. I was wondering if I could go to a auto store and match the condenser up with some thing there?
Thanks for help in advance and have a very merry christmas
Cheers

If auto parts stores are like the ones here they can't do anything except give you what the computer says; otherwords, no real knowledge of anything.

It does sound like point and condenser. Also check high voltage lead for breaks. I have seen a few old trimmers and mowers where the plug clip would break the lead wire causing loss of spark at random times.

if the carb was full of gunk, it will most likely need to be cleaned in an
ultasonic bath, and maybe a few times, i would make sure it is properly
clean before i moved on to something else, like electrics.

Hello RSB, AVB and Squizzy

The odd thing is the hunting.
I know worn butterfly shafts cause a lean mixture that may
result in engine hunting. Perhaps that could be checked.

If the coil or condenser break down, then I guess you would
get a hit-and-miss effect (a misfire) - similar to hunting,
although 'hunting' is better related to governor or carby issues.
Misfire is more like an on/off switch.

The condenser would be the first point of call for miss-fire,
but Squizzy's advice seems sound too - and the first approach.

Is the symptom hunting or misfire?
The ODK Parts site may offer some assistance on sourcing ignition parts.

Please let us know what transpires.
----------------------
Jack

Thanks for the info guys. I am going to go for a new B/S motor, when I get time to repair the frame.
Thanks again