I have received some great responses from the Luscombe groups and from general aviation forums about this issue. Just in case other folks have the same problem, I have included a summary of options below.
I have flown behind this engine for 600 hours, and I love it. However, when we inherited Keely, our eleven-year old, my flying habits changed. Instead of flying for hours at a time, most of my flights are an hour or less now unless we plan a trip or I have a day off. Henry, my hubby and IA, thinks this pattern change as contributed to my problem.
Here's how I plan to approach the issue. First, I'm going to learn to clean and gap my plugs. I do a lot of other stuff. I might as well learn to do this. In the past, Henry was at work during the week and only home on the weekends. He is retiring in at the end of the year, but I think I still need to know how to do it. I will keep a chart of how often I clean and gap them. I will note condition, etc.
I will revise my shutdown procedure by running up and shutting the engine down with the fuel instead of the mags. I plan to change my plugs to the REM37BY. I've heard only positive things from folks who do this. And I plan to reinstall the mixture control on my Stromberg to see if it will help.
Here's the ideas offered:
-Shut down by turning off the gas instead of the mags while running at least 1000 rpm to keep the heat up on the plugs. Just don't forget to turn off the mags after the engine quits.
-Change your spark plugs from the REM40E's to REM37BY spark plugs.
-Put 1 ounce of TCP to every ten gallons of fuel.
-Adjust the idle mixture screw on the carb.
-Adjust the float. Shops often set them too high thinking you can lean.
-Reinstall the mixture control on the carb. It does work, contrary to what many will tell you. The biggest problem with a Stromberg is that they aren't as well understood by many mechanics today as in the past. If all is working as designed, you shouldn't see any differences in flying behind a Stromberg or a Marvel... except for the mixture idle cut-off and the accelerator pump thingies.
-Sure you can put a Marvel-Schebler on your engine... if you can find one. The C-85 carb is
very scarce (p.n. 10-4240 or 10-4240-1). Tempest is the new owner of these carbs.
http://www.tempestplus.com/home.htm They just announced a price reduction on all carbs and rebuilds. You might give them a call and see if they have any new 10-4240 carbs available. Rebuilds usually require a core carb but call 'em to verify that. Even with the announced price reductions, be prepared for a price tag that may take your breath away.
-Another option is an STC that allows the use of a modified O-200 Marvel-Schebler carb on the C-85. It's STC SE01309AT. That STC modifies an O-200 carb (p.n. 10-4894) for use on the C-85. I'm pretty sure the mod has to be done by the STC holder... Lowe Aviation in Sacramento, KY. It's also a little pricey if I remember right.
Thanks again everybody!
Deb