Auto chokes give excess fuel through a passage when the carb is cold. An electric heater, run directly from the alternator, warms up and a thermostat cuts the fuel to the excess fuel passage. You can usually tell if it is working. I have a Buyang in at the moment, starts with fairly high idle speed, then the engine note alters as the choke turns off and revs drop.

 

Ok,.. what are the procedures in checking the auto choke ? ( As this was running engine before a heavy frost )

 

Because the choke is on when engine is cold, they tend to fail making choke on all the time rather than what you think you have. There are other things that can cause an engine not to start and, in frosty weather, a bit of water in the carb which has frozen, would be one. You can take the carb apart and check if the excess fuel passage is open but working out which passage that is, isn't the easiest job. Personally I would see if it starts in warmer weather and listen to the engine, revs rising rather than falling, as it warms at idle, would indicate the choke hadn't been on.

 

What i've found with the start ups, if you have the ignition on , And forgotten that the kill switch is still on position , There seem to be a compression noise from carb when turning kill switch off whiles ignition is still on. . I've found engine just seems too crank over and not start !! , I then found replacing the spark plug fixes the problem engine starts , this has occurred several times , Spark plugs look to be fuel fouled I'm not sure if this is the choke related issue t or something else .

 

You "wet the plug" fairly quickly if you are turning the engine over with no spark to fire it up. It does this quicker if the choke is on, but will do it. That is one reason I use a gas blowlamp to help start a reluctant engine, a sniff of butane gas down the air intake richens the mixture but doesn't wet the plug if the mixture is too rich to fire.

 

Okay , the auto choke doesn't seem to be operating as the engine revs are at idle on cold start thinking the manual choke conversion on this CVK30mm carb may help solve problem

 

Yes, if you think you would prefer a manual choke, go for it.