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| Large Engines Discuss Engines Used on Giant Scale Aircraft. Gas/Glow, as long as they're big! |
Topic Review (Newest First)
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| 09-21-2016 02:00 PM | ||||
| grosbeak |
Re: RCGF 30 twin won't start Quote:
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. |
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| 07-19-2016 07:55 PM | ||||
| Trumpetman |
Re: RCGF 30 twin won't start Don't you hate when that happens! Well at least you know the carb is in good shape! 
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| 07-17-2016 06:36 PM | ||||
| grosbeak |
Re: RCGF 30 twin won't start Got it started this morning. The cause of my troubles? Reversed throttle servo. :0 |
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| 07-15-2016 12:26 PM | ||||
| grosbeak |
Re: RCGF 30 twin won't start Quote:
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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. |
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| 07-15-2016 10:47 AM | ||||
| Flypaper |
Re: RCGF 30 twin won't start 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. |
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| 07-15-2016 10:05 AM | ||||
| grosbeak |
Re: RCGF 30 twin won't start Quote:
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| 07-15-2016 12:45 AM | ||||
| Jimmy P |
Re: RCGF 30 twin won't start Just looking this over here, originally you said the cylinders were dry and no go. After looking at the picture it appears that both needles look very close to the same, any chance they at the factory put the two needles in the wrong holes? It could be a new person put it together and they are backwards. I would go there myself they make an excellent engine. |
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| 07-14-2016 09:59 PM | ||||
| grosbeak |
Re: RCGF 30 twin won't start This evening I took the carb off the engine for a look. I removed the fuel pump cover to make sure the rubber plate wasn't sticking. No problems there! I removed the needles for a look. The low was reinstalled at 1-3/4 turns open. The high was opened 2-1/2 turns. Time to lap the carb and reed block mating surfaces. The carb was especially rough. Before... Lapping After One reed wasn't seating properly either. All the mating surfaces were lapped except for the crankcase. The gasket appeared to be adhered so I left it alone. Next - the timing. This is the position of the sensor relative to the magnet at 28º BTDC. I don't know enough about these things to tell whether the sensor is correctly positioned for 28º but it looks pretty close. It was dark by the time I finished so no test start tonight. Tomorrow... |
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| 07-14-2016 02:08 PM | ||||
| grosbeak |
Re: RCGF 30 twin won't start Quote:
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| 07-14-2016 10:36 AM | ||||
| mogman |
Re: RCGF 30 twin won't start It shouldn't matter where the plug leads go. Both cyls fire at the same time. Try opening the low to 1-1/2 turns out. As mentioned, make sure there are no air leaks around the carb base and reed valve block. Also, make sure that the carb pump "flapper" valves are not stuck to the carb. If the engine has never run before or if it has sat for a long time, these little flappers can stick to the carb body. Just lift the edges a little a put a little gas on them. They are under the cover with the single central screw. |
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