Hayter 56 running rough

Hi, I wonder if someone can help....my hayter 56 smokes (white) on start up then clears...this has happened for a while...however it has now started to rev up and down and only running smoothly when I tilt the mower backwards...I have had the spark plug out and cleaned it...the oil level could be slightly high...the air filter appears clean...the fuel has not changed...any ideas? Many thanks, Adrian

 

Had this problem on my 48 pro. Went in and was told it could be several probs. turned out to be rubbish in my carb and I've a filter in place now to stop rubbish entering the carb.
They did mention about a gunk up issue which can cause it, I can't remember All what they said but it was expensive. Could be spark plug was the other or damage to carb due to petrol deterioration.
Mine is the more modern version a 2008 model.
My symptoms was it would start fine, run ok then hunt. I don't tend to to mess about and just let my local dealer look at them while I carry on with my other machines.

 

Thanks guys, I've contacted hayter and their initial thoughts are dirt in carb so take to a repairer. I may drain off some oil first as could be high and see what happens. Cheers for help.

 

I'm not sure what age your mower is but if to the newer type Hayter and turns out to be crap in the carb ask them to fit a filter on the fuel line. This will save any more issues with rubbish entering the carb.

 

it is pulsing up and down because of a dirty carb....the white smoke is a result of worn piston rings or in this case I think, to much oil in engine....to much is as bad as to little...fill to correct level and smoke issue will be sorted...you can clean carb yourself!...just watch a few how to vids before doing so..

 

Hunting, revs rising and falling rythmically, is usually running rich. That means it is getting too much fuel for the amount of air getting through. People forget how important the air filter is - if you work it out as to how much air an engine uses compared to fuel you will start to understand why the air cleaner is one of the most imprortant parts. A 100cc engine running at 5000rpm burns about 1 litre of fuel per hour.
Now work out how many revs the motor does in that hour (5000 x 60 = 300,000). That allows us to work out the swept volume the piston covers in that hour. 300,000 revs at 100cc = 30,000 litres. If the engine burns 1 litre of fuel in that 30,000 litres, then it uses 29,999 litres of air for each litre of fuel. Everyone reckons the fuel filter is important but they overlook the air filter, which does far more work than people give it credit for.
If you overfill the engine with oil very often this increases the pressure in the crankcase and will blow a seal (in a car, often to contaminate the dry clutch, which then slips). Otherwise it will blow by the piston rings and gum up the plug in the short term and coke up the valves in the long term.