G5 poor running.

crawsue · Post by **crawsue** » Thu Mar 02, 2006 7:25 pm

The G5 that I have been re-building over the last few months is now virtually complete,it starts 2nd or 3rd kick ,ticks over nicely,and pulls while accelerating (right word? !!) without any mis-fires.Problem is on an even (cruising) throttle it "hunts".Spark plug is an NGK-6,gap OK,and timing seems fine ,contact gap as specified.I'm not too good on carb. set up,any hints would be appreciated.CR

Don Madden · Post by **Don Madden** » Thu Mar 02, 2006 7:40 pm

"Hunting" at part throttle is a classic symptom of lean mixture at the that throttle setting, but also check that the auto advance unit is in good condition & works smoothly. Wear can cause them to bind in the retarded position as well as a sloppy timing curve.

crawsue · Post by **crawsue** » Thu Mar 02, 2006 7:44 pm

Many thanks ,Don, as I said I'm not too good at this bit ,can I adjust the mixture by moving the needle? If so up or down? !!CR

lawrence · Post by **lawrence** » Thu Mar 02, 2006 8:22 pm

Move the needle up to richen it. Buy a colortune off eBay and then you know you have the setting right. Otherwise do a check on the spark plug. After a run it should be a nice light tan colour. Sooty black = too rich, white = too lean. Too rich is better than too lean. Just right is best

crawsue · Post by **crawsue** » Thu Mar 02, 2006 8:54 pm

Thanks for that,carb' will get a looking at to morrow,as will spark plug ! CR

Michael · Post by **Michael** » Mon Mar 06, 2006 4:14 pm

Coulor tune sparking plug is a very good investment.

Did I understand it correctly that "hunting" means kicking back ?

If so, I suggest checking the advance/ retard system or just retard ignition during the starting phase.

Michael

Don Madden · Post by **Don Madden** » Mon Mar 06, 2006 4:32 pm

Here in the US "Hunting" is the surging, followed by lagging, feel when on the road at a fixed speed & throttle position, as the carburetor fails to provide the correct mixture. Usually caused by a lean, (weak), mixture. I believe the Brits use the term similarly, but there are variations in our common language.
Cheers, Don.

Eric · Post by **Eric** » Mon Mar 06, 2006 5:34 pm

Hi Don we are two nations separated by a common language, but you will be pleased to know that hunting in this case means the same this side of the pond as it does on yours. I guess someone decided that it was as though the engine was searching around for a steady speed so it became known as hunting.

crawsue · Post by **crawsue** » Mon Mar 06, 2006 7:13 pm

crawsue · Post by **crawsue** » Mon Mar 06, 2006 7:18 pm

Yup! My idea of hunting is exactly that,surging then falling off.I moved the needle up a notch and it seems a lot better,but with the weather and road conditions up here at the w/e I couldn't road test it very well.My pet "guru" has a colour-tune kit which we can try if the situation demands,although getting access to the top of the 'carb when the tank goes back on does not look too easy!CR