[Flypaper]

Make sure the plane is tied down well. Squirt some gas right in the carb throat. This bypasses the carb altogether. Set the carb at about 1/4 throttle. Now give it a go. It should start, rev up and then quit as it burns out the fuel.
This lets you know it's a fuel problem and not ign.
If you do get it going this way, once it starts you should be able to keep it running with the choke partway on. If it does so, open the jets a bit at a time and lessen the choke. There should be a point where you can get the choke all the way off.. Now open the throttle till it starts to stumble and open the high speed jet to see if it smooths out. Keep doing this till you get to full throttle
Now slow it down add go through the same procedure with the low mixture till you get a good idle.
I have run into new carbs with machining particles in the jets and have to be blown from the inside out. and the ones that have the little welsh plug, have to have it taken out to clean out the three jet holes , inside.
Hope this helps.

[grosbeak]

Originally Posted by Flypaper

Make sure the plane is tied down well. Squirt some gas right in the carb throat. This bypasses the carb altogether.

Gas is getting through the updraft carb - I can tell because it drips out. And gas squirted up the carb would also drip out.

Set the carb at about 1/4 throttle. Now give it a go. It should start, rev up and then quit as it burns out the fuel.
This lets you know it's a fuel problem and not ign.

With diagnostics I've already done and what I've learned during the process I'm pretty sure the ignition is fine. It seems to be a problem of fuel not getting to the plugs with the choke open. Note that I've opened the low needle to 1-3/4 turns and will open it more if necessary to start the plane.

If you do get it going this way, once it starts you should be able to keep it running with the choke partway on. If it does so, open the jets a bit at a time and lessen the choke. There should be a point where you can get the choke all the way off.. Now open the throttle till it starts to stumble and open the high speed jet to see if it smooths out. Keep doing this till you get to full throttle
Now slow it down add go through the same procedure with the low mixture till you get a good idle.
I have run into new carbs with machining particles in the jets and have to be blown from the inside out. and the ones that have the little welsh plug, have to have it taken out to clean out the three jet holes , inside.
Hope this helps.

Thanks Flypaper. This would have to be done a bit at a time as neither the choke nor the needles are easily or safely accessed with the engine running.

My plan for tonight is to try again with the starter. Choke closed, three clicks of throttle, starter, engine burp, choke open, 1/4 throttle, starter... If it doesn't start with the low needle at 1-3/4 turns open I will open it a little further and repeat the process until it starts or it becomes clear that it will not.

[grosbeak]

Got it started this morning. The cause of my troubles? Reversed throttle servo. :0

[Trumpetman]

Don't you hate when that happens! Well at least you know the carb is in good shape!

[grosbeak]

Originally Posted by Trumpetman

Don't you hate when that happens! Well at least you know the carb is in good shape!

You know it!

This past weekend I took this version of the airplane to the field for the first time. A fellow club member was a big help in getting it tuned.



When I cut full throttle to idle it runs fast for ten or fifteen seconds. I understand one possible cause is the fact that the engine is new and not broken in; in any case it's not a big problem because most of my landing approaches use a more gradual throttle reduction. :P

There was a fair bit of wind but mostly it was straight down the runway so I decided to try a flight. The engine ran well... some midrange four-stroking but I'm not concerned about this for the time being. Most of the flight was at 1/4 to 1/3 throttle. The high wind made it interesting... I shot a couple of practice approaches to get used to the conditions and how the engine behaved, then came in for a decent landing. I got the plane down in one piece so it lives to fly another day.