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**flyguy** · 07-27-2008, 08:56

Re: High fuel consumption

Danny, don't know anything about the O-200 crank, but that is really high fuel consumption. Got to be something wrong with your carb. I have 85 and it burns about 5 at the most. I guess I would look at the exhaust pipe color first, looking for black instead of gray.
I doubt if a rich mixture adjustment would cause it to be off that much, but it would'nt hurt to tweak it, if you know how. Be careful.
Possibly float level is too high. Can't think of anything else just now.
Mixture contol is doable on these carbs, contrary to popular opinion, but you want to get the carb working correct first before you consider taking on that little chore.
Darryl

**Guest** · 07-27-2008, 15:45

Re: High fuel consumption

Originally posted by DannyDot View Post

I have a C-85-8 with the O-200 crank in my plane. At 2300 RPM it burns 7.0 gal/hour and at 2200 it burns 6.5. I think this is way too high. Any ideas on how to get the burn rate back to where it belongs. I assume carb work would be needed. Anybody know of a mod to put a leaning carb on a T-craft.

Danny

Hi Dan, couple of thoughts, is the tach accurate? is there a fuel consumption or hp curve in the c85 manual that you can compare yo?

Dave

**NY86** · 07-28-2008, 09:14

Re: High fuel consumption

What prop are you swinging? what airspeeds are you seeing? (accuracy?) also, as previously mentioned, get the tach checked. If you're using auto fuel the exhaust will be black regardless of how it is running.

Have you checked the other usual suspects: Cam and ignition timing, valve lift, intake filter, etc?

As far as the mixture control is concerned, the C85 is not certified with any carb that does not have a mixture control, so if you don't have one, well... (Should be no more than adding the control cable!)

**astjp2** · 07-28-2008, 10:53

Re: High fuel consumption

I had a marvel dribbler that I put the 1 piece venturi in and the discharge nozzle for my O-200 and I was burning around 8 gpm, I spent 2k on overhauling the carb by a professional shop and after sending it back twice, It still ran goofy, I put the 2 piece venturi and discharge nozzle back in and I am down to 5.5 gph in cruise. Tim

**flyguy** · 07-28-2008, 13:42

Re: High fuel consumption

That seems to indicate that there is a real problem with the one piece venturi conversion. Anyone else have a similar experience? Comments appreciated.
Darryl

**DannyDot** · 07-28-2008, 16:51

Re: High fuel consumption

Originally posted by NY86 View Post

What prop are you swinging? what airspeeds are you seeing? (accuracy?) also, as previously mentioned, get the tach checked. If you're using auto fuel the exhaust will be black regardless of how it is running.

Have you checked the other usual suspects: Cam and ignition timing, valve lift, intake filter, etc?

As far as the mixture control is concerned, the C85 is not certified with any carb that does not have a mixture control, so if you don't have one, well... (Should be no more than adding the control cable!)

I think I will fly as is until I have my cowling off in Aug for my next annual and see what carb is on the thing and hook up the mixture control if it has one. If it doesn't, I will look into buying a carb certified for my engine. I would hate to do anything not 100% certified by the FAA :-)

Danny

**whake** · 07-31-2008, 19:33

Re: High fuel consumption

I have a c-85 in my Ercoupe. I burn about 5.25 GPH, it has a mixture control but I leave it full rich, no cly hd temp gage. I cruise it at 2350 rpm. I gave up my T-craft for a starter. I like tthis web page better than the Ercoupe web page. No tech help.

**Forrest Barber** · 08-01-2008, 06:51

Re: High fuel consumption

We used to have a lot of Ercoupes here too! I love them, keep in touch.

**Larry Lyons** · 08-01-2008, 13:30

Re: High fuel consumption

Krog and the guy from Dream Machines both commented on the better performance with this combination but the issue of fuel burn did not come up at the Taylorcraft forum.
Larry