Earthstar Forums

Several weeks ago after I completed installation of my re-designed instrument panel, I attempted to start the engine for a test prior to putting the plane back in service.

It wouldn't start. After finally exiting the plane to look for obvious problems, I saw that gas was dripping out of the air cleaner.

That set off a long series of "fixes" before I finally found the real problem. Among the fixes was a new Mikuni fuel pump, complete replumbing of my fuel system to change it back to a parallel system (separate lines for Mikuni and the Facet electric pump to tees in the inlet lines to each carb, etc. I also removed the carbs and sprayed a 50:1 mix of gas and oil into the engine intakes and (with spark plugs removed) spun the engine by hand many times to make sure the crank and cylinders were well lubricated in case raw gas had made its way into the engine. Without the engine running, very little oil gets in via the injection pump.

The final step was a complete rebuild of each carb. What I then discovered was an abraded float and a possible minute crack in the other float in #2 carb. I probably caused the abrasion to begin when I had trouble putting the carb bowl back after changing the jets back to stock when I removed my HAC system just prior to the problem.

The floats were about 14 months old. I replaced the old single float system with them in Oct. 2010 when I previously rebuilt the carbs.

Aircraft Spruce gets $33.50 each for the two floats required in each carb.

Finally, with my new fuel routing, my new floats, my new jets, etc. the engine fired up, ran smoothly, and the plane took off and climbed like it had JATO bottles on it. I attribute the performance to the OAT of 48 degrees F.

And the new EIS worked beautifully, with temps within 20 degrees of each other. Sure took a long time to get the CHTs above 200 on the ground in that cold air, however.

(I know, my northern friends will laugh at considering 48 to be cold. But I'm a Southern California boy, so give me a break.)

Dick

Richard...... Was that 48 below, or above? It was 37 below in West Yellowstone, Montana a couple of mornings ago.

Interesting account of your experiences. I'm wondering...... Why did you decide to remove the HAC system?

Riley

Riley,

The plane had not been running right since last spring when I had four momentary
power losses that led to a precautionary landing on El Mirage lakebed
(http://www.youtube.com/user/ManyPerspec ... bGEcEFZ5a0).
When I had another power loss at El Mirage in August, the cause looked to be an
over-rich mixture.

Mark's recommendation was to get rid of the HAC, restore normal jetting and keep
things simple. He said that when he was flying Gulls with 503s, he set up for an
EGT of 1150 at near sea level cruise and left it alone. He said he never changed
jets after that on all his many criss-cross-nation flights.


So that's why. My initial test flight indicates he was right. But I still need
to get the carbs balanced. I ran out of time the other day to do a thorough
mechanical/eyeball setup, so that's the next step. Probably tomorrow.
 Dick O'Reilly

I was wondering about disarming the HAC on mine. As far as jetting goes, I flew a 447 Rotax single carb for 800 hours in Montana for years. I normally flew between 3000 ft and 8000 feet elevation, but went to 13,500 a couple of times. Mixture and EGT never seemed to be a problem. The only time I changed jets was for summer and winter.