Carburetor settings at delivery from your workshop

Hi Jabiru. Coming back to this issue. I was not able to log in on my original account, and when asking for a new password I was told the account did not exist? I therefore made a new account. So I am still Olav Soendergaard Poulsen.

Since last communication, I have flown my FlySynthesis Storch HS reluctantly accepting a fuel consumption of 17-18 l/h at 2700-2800 rpm and a EGT around 650-675C. My IAS is then 160-165 kph. In wintertime probably 170 kph. Last week I flew from Denmark to Budapest and back again in 30-35C temperatures at ground level, at altitudes of 2000-4500 feet. In the hot thin air with two persons on board and max weigth, the fuel consumption was about the same as at home, but IAS was only around 145 kph. The EGT was typically 630C and on one particular hot day at high altitude it went down below 625C. That is too cold, and my spark plugs are telling me the same story - quite black though not shiny black.

I want to trim my mixture, but I am a bit confused about my carby setting. I have got a size 255 main jet and a size 2.76 needle jet. I don't know yet what needle I have got. It is most likely what was installed from Bundaberg, og Fly Synthesis might have changed it. The first owner have not changed it, and I am the second owner of the plane. I have tried just putting in a size 250 main jet, but that only makes the EGT go a bit higher during take-off and climb. No effect in cruise and cruise is my main interest. So I want to replace by needle jet to a size 2.74 or size 2.72 or even a size 2.70 to get better behaviour in cruise. But I wonder - isn't the size 2.76 already a quite small needle jet?

I have checked the air filter if it could be the reason for the rich mixture. Well not exactly looking as brand new, but I only see about 1/3 of the filter area having changed its colour from yellow to greyish. Will replace it though, or make a short flight without the filter to rule out the filter as the cause of rich mixture.

My J2200 runs at 2750-2800 rpm at full power ground test before take-off. Fuel flow according to my fuel flow meter is then approx. 25 lph. During climb at full power I see rpm around 3000, and at horizontal full power flight at 195 kph it runs at 3200-3300 rpm.

Based on the rpm's my engine runs at the different conditions, I believe my propeller fits the plane quite well, and the engine is running very well without any hick-ups. I just want my EGT to be a bit higher and my fuel consumption a bit lower. I primarily use Shell V-Power 99 octane fuel, and use 100LL as alternative. To be honest I cannot feel the difference between standard 95, V-Power 99 or 100LL fuel. The engine runs smooth on all three and the consumptions seems to be about the same.

Hope you can give me some advise. Regards Olav Poulsen

Hi again. Just had a closer look at my carburetor. It appears that what probably is the original settings are engraved on the carburetor. It says M225 N280 and Needle 4A138AOD-1. Below there is another number 17681 engraved - is this the Bing serial number? These figures are they the settings when the carburetor left the Bing factory, or is it the settings from Jabiru or could it be the settings from when it left the FlySynthesis factory in Italy?

However. What I find in the carburetor today is a size 255 main jet and a size 2.76 needle jet. I have not checked the needle yet. But would the needle 4A138AOD-1 be the right needle, or would you suggest another one?

Best Regards Olav

This is the needle I have got. Can you confirm it is the 4A138AOD-1 needle?

Regards Olav

Hi Olav,

We had to change the forum software which has caused a few issues - including me not seeing your recent posts.  Apologies for the delay in replying.

The identifying marks (the little rings below the clip) do appear to indicate that the part is a 4A138A0D needle.  However, the drawing for the 4A138A0D needle that I have only has 1 circlip grove, located at 4.5mm from the top of the needle.  Compared with that, your needle has 3 additional grooves - and they appear to be lower than the original.  The clip is in the lowest position, which would tend to raise the needle and make your fuel mixture richer.  So, going off that photograph, your needle has been adjusted to make the mixture richer.  Quite a lot richer.  That's not totally unheard-of, though I would generally be uncomfortable with such a large adjustment because the needle design is not a traditional taper and large adjustments can have unexpected effects.

The good news for you though, is that it looks like you've found your issue, and if you move the circlip to a higher groove then the mixture will become leaner, EGT will increase and fuel consumption should decrease.

Best Regards,

Doug.

Thanks Doug. I hope soon to have a chance to do a flight test with reduced mixture.

I will keep you posted on which settings I end up with.

Regards Olav.