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carb heater

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carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Graham H on 15:44:19 12/18/14 Thu

Are the carb heaters for the Bing carburettors still available and do they help with cold starting problems.
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: DL on 12:04:41 12/12/14 Fri

IMHO they as as useful as a fart in a spacesuit!

Pretty useless as far as I am concerned. best thing for easy starting is drilling out the choke jet on Bing ...

1.0mm for 2200
1.2mm for 3300
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Keith Betteley on 15:53:43 12/12/14 Fri

Every year when the temp drops to below 10 degrees cent I have had to apply hairdryer heat to the carb of my J300 for a few minutes in order for it to fire up. So this year whilst having the 1000hour tbo I had the choke hole drilled out. This last week I had the opportunity to get airborne on 3 occasions, the first time with the air temp at around 8/9 degrees she started okay on the second attempt, the second time the temp was about 6/7 degrees no luck, so out came the hairdryer. The third time with the temp at about the same I switched on the carb heat for a few minutes and she started first time. In future I will go down this route as it would appear to work perfectly and do not have to remove the top cowling.
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Keith Betteley on 18:42:42 12/12/14 Fri

Just in case anyone thinks I'm testing out a new Jabiru prototype, what I meant to write was J400 and not J300.
Apologies for any confusion
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Steve on 19:19:56 12/12/14 Fri

The electric carb heaters are great for controlling carb ice (I am assuming these are ones you mean) but I cannot see them making much difference to the cold starting. They only heat a specific area of the carb to help stop ice sticking. With both on, it is only 60W of heat. In some situations, they could make the starting worse as with both on, they draw 5 amps so leaving them on for an extended time before starting could quickly drain the battery down.

There are carb blankets I saw somewhere that you wrap around the carb and then power from a 12v source but you have to put this on each time you use it and would ideally need an external power source to stop drain on the aircraft battery.
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Matt on 18:24:12 12/13/14 Sat

Skycraft list a cold start ignition module kit!
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Graham H on 16:17:51 12/14/14 Sun

Thanks lads, sounds great great DL. Has anybody got a spacesuit!!!!
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:13 pm

Posted by: Gary on 17:25:10 12/14/14 Sun

Graham, like deano says i dont think the carb heater will aid cold starting, they are for carb ice melting. Drill the choke jet. My jab will start in minus 10 (2years ago when it was) on 3 blades, bugger to get the oil temp up though, even now in this cold spell. I have the electric and manual carb heat fitted. The electric one is one all the time, but I still use the manual carb heat. Trouble is you dont know if the electric 1 is working unless you pop the hood and feel them. I have in the past had a bad connection on the post terminals and even though the dash lights indicated they were on, they were cold!! So the system in not fool proof
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:14 pm

Posted by: Steve on 21:51:08 12/14/14 Sun

Gary,

Just put a current monitoring gauge in there. You can tell instantly if it's working. Each heater draws about 2.5amps. If it isn't working the current monitor won't change when you switch it on.
Anonymous
 

Re: carb heater

Postby Anonymous » Tue Feb 10, 2015 10:14 pm

Posted by: Peter Knight on 09:34:04 12/15/14 Mon

I have no doubt that drilling out the choke jet and making sure that the throttle is fully closed are the two best ways of ensuring that the engine starts in the cold.

I did think of installing the Jabiru Cold Start Kit but when I enquired at Skycraft there was some problem with it and they had withdrawn it from sale. (This was about 12 months ago so things may have moved on).

I tend to switch the electric carb heater on for about 3 - 4 minutes when I am doing the checks on a really cold day. This has little impact on the battery but does have the effect of warming the carb and the fuel in the bowl. This presumably gives better vaporisation and a better likelihood of starting. Of course I don't know that the engine would not have started anyway if I hadn't have done this!

Final point on the carb heater; I have installed a digital thermometer on the carburettor. This gives an excellent indication of the temperature of the carb body and will show you if the carb heater is working. It also gives a clear indication of how long it can take for the conventional carb (hot air) heater to work. If the engine has only just been started the hot air carb heater can be useless for the first 5 mins or so, in other words it may not help much if you are taxing out over wet grass to take-off. Just when you need it most.

The LCD digital thermometers used to be available from Maplins but Vic sells them on this site. Well worth installing and simpler (more information) than a current meter.

Peter
Anonymous
 

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