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Jonspn · May 23, 2007, 12:12 PM

Hi,

This unit has given years of faultless service, Until now. The engine always starts but after about 15 minutes will start to hunt. Then it will cut out completely. You can then restart it immediately but it will only run for about 10 minutes. I have changed the Oil and the spark plug. My next task will be to swap out the coil.

Any ideas ?

Jonspn · May 26, 2007, 10:45 AM

Changed coil and fuel filter, Still cutting out. Carb looks clean, with bowl filling with fuel OK. Not sure what else there is left to check.

newaukumdon · May 26, 2007, 11:58 PM

Hunting is a sign of fuel starve. Fuel getting into the bowl is the easy part, once in the bowl it is drawn into the throat up through the stem and through a proper sized nozzle. If these are slightly dirty it will starve and hunt. Try choking it a little when it hunts if it starts to smooth out it is a fuel starve.

Don

Jonspn · May 27, 2007, 01:45 AM

Don,

Thanks for the info. Pulling the choke out when the engine starts hunting does make a difference. The engine picks up and runs a little longer, however it still dies and does so without warning. I suppose the fact that the choke has an effect means that the issue is fuel related.

Looking at the carb with the bowl off it looks as if the stem is screwed in. Is it easy to remove and check or would your advise be leave in situ to blow it through ?

Thanks for your help.

Jon

newaukumdon · May 27, 2007, 08:40 AM

If you have the carb removed and see the stem (main nozzle) remove it, behind that you will find a pilot jet remove it also (presses in) and clean both well.

Don

Jonspn · May 28, 2007, 07:48 AM

With the carb off and bowl removed, I unscrewed the main jet. The other Jet was screwed in from the top of the carb. I didn't see any obvious push together parts, but cleaned these jets and made sure that the cleaning fluid came out of all the perforations.

Ran the engine again, but still hunted then died after about 10 minutes. The only obvious thing that I can determine is that it only does this when the engine gets hot. Pulling the choke out does prolong running, but eventually the engine dies even with the choke out.

Jon.

newaukumdon · May 28, 2007, 10:57 AM

Check the flow of fuel from tank to carb, it may be a partial block in the tank or filter. Check the fuel cap vent as well and lastly does it have a fuel cut solenoid on the bottom of the carb? These sometimes will fail.

Don

Jonspn · May 29, 2007, 12:12 PM

Don,

Thanks very much for all your help. What I thought was a good flow out of the fuel pipe was in fact a trickle. A quick clean of the pipe brought down a few leaves followed by the required gush of fuel. It's a bit wet to cut the grass at the moment, but I left the mower running for a while and it did not cut out.

Thanks again.

Jon