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Old 09-10-2019, 07:21 AM
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DA100L ISSUES

Hi Guys,

I have a DA 100L and he has been having problems at the time of the first startup of the day.

He doesn't give the initial "pop", but the carburator is full of gasoline.

It looks like gasoline doesn't go to the cylinder.

I replaced the reed valve and de carburator and it didn't solve.

After removing the spark plug on cilinder, it starts and works normally. what may be happening? I remember it's just the first startup of the day.

Thanks.

Fernando
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Old 09-10-2019, 03:19 PM
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I would check to see that your choke plate is closing all the way, and that your LSN is not way too lean.

beyond that could be a diaphram issue, or small air leak in fuel system not allowing pulse port pressure to push fuel into carb and hold it there

Or on the complete other side of the spectrum it could be to rich and just flooding right off the bat. If you say you pull the spark plus, then it starts, are they wet?
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Last edited by Show871; 09-10-2019 at 03:30 PM.
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Old 09-10-2019, 03:29 PM
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Quote:
Originally Posted by NANDOJ View Post
Hi Guys,

I have a DA 100L and he has been having problems at the time of the first startup of the day.

He doesn't give the initial "pop", but the carburator is full of gasoline.

It looks like gasoline doesn't go to the cylinder.

I replaced the reed valve and de carburator and it didn't solve.

After removing the spark plug on cilinder, it starts and works normally. what may be happening? I remember it's just the first startup of the day.

Thanks.

Fernando
You may want to open the throttle a little bit when you have the choke closed.
sometimes if the throttle is too closed up it wont allow it to suck the fuel in.
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Old 09-10-2019, 03:32 PM
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Is the carb pointed down? If not, you describe a flooded engine.

If the carb is pointed down as always it still sounds flooded as that's about the only difference pulling and installing the same plug will do - help air out (clear) a flooded engine. Otherwise, it's back to carb basics like above and a possible air leak. Loose carb, leaking gaskets or seals. These improve sometimes with heat.
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Old 09-11-2019, 06:43 AM
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Yes, the carb pointed down.

When I pull the spark plugs they looks like dry...
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Old 09-11-2019, 07:02 AM
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So it starts only after pulling the plugs? The only change being made here is from moving the plug wires around. I have one engine that will run like garbage, die, and is hard to start until the plug wire is moved as it has a bad plug cap. I doubt this is the issue with a twin but don't overlook the possibility.

The dry plug makes me think the carb is still at fault. Is the fuel tank close and somewhat level with the carb? It is likely draining gas back to the tank when sitting overnight. A simple test of this is to prop the tail of the plane up after the next flying trip so the tail is even with the engine or a bit higher. If this solves the problem you have a carb allowing gas to drain back to the tank and it has to be primed after sitting overnight. If so it's not really a defect, it's just not convenient. Some carbs just do this and raising the tank may help.
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Old 09-11-2019, 07:29 AM
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This problem has started now and without having a specific cause. The engine always worked well about 8 years, I never moved anything ...

The carb is brand new original Walbro WJ71... The reed block is brand new from DA...

I'm thinking of replacing all engine gaskets and fuel lines and seeing what happens.
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Old 09-11-2019, 09:18 AM
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8 year old engine. Have you checked for a stuck piston ring? This will cause hard starting and is often overlooked. Maybe time for a DA checkup.
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Old 09-11-2019, 10:13 AM
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Have you checked for a stuck piston ring? This will cause hard starting and is often overlooked. .
No, I haven't

But I've decarbonized it twice in this 8 year period and haven't noticed anything unusual.

I will look again more closely
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Old 09-12-2019, 06:50 AM
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So it starts only after pulling the plugs? The only change being made here is from moving the plug wires around. I have one engine that will run like garbage, die, and is hard to start until the plug wire is moved as it has a bad plug cap. I doubt this is the issue with a twin but don't overlook the possibility.

.
f it was plug problem I understand that the engine would not work well, but it works.

It's only about the first trigger of the day.
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Old 09-12-2019, 08:40 PM
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Man I feel for you. I have a DA100L on a hangar 9 Beast and what a gem of a motor. Easy to start and will pull the 30.0lb beast out of the hole in a hover like an indoor foamy with a falcon 28x9.5 carbon flagon prop. Let us know when you get it running and the cause..

D.
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Old 09-13-2019, 07:25 AM
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Originally Posted by NANDOJ View Post
f it was plug problem I understand that the engine would not work well, but it works.

It's only about the first trigger of the day.
If your plugs are dry, and only the first start of the day I would say your not drawing the fuel you used to to get it to pop. I would make sure your choke plate is sealing, and triple confirm you dont have plumbing leaking air slightly and not allowing the fuel to get the first push into your carb. Take your hatch/cowl off and watch your fuel line when someone flips your engine with the ign off. You should be able to see fuel moving toward the carb when you flip
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Old 09-13-2019, 07:39 AM
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Originally Posted by Truckracer View Post
8 year old engine. Have you checked for a stuck piston ring? This will cause hard starting and is often overlooked. Maybe time for a DA checkup.
Not necessarilly, but good thought. I had a 3W 157 TS/CS, and I was having a hard time keeping temps down on 1 cylinder. It was 100F hotter than the other. Pulled plugs, matched the other cylinder in color. Fired up without the cowl on, and sprayed brake cleaner all over the engine. The brake cleaner would not cause any erratic running, when sprayed over the gaskets. Ended up pulling the heads off, and found stuck rings on 1 cylinder.

I think he needs to choke and start on an idle up function. Peoe who start with 1/4 throttle advanced scare the doodoo out of me. I personally always trim up my throttle for choking and starting. I love my analog trims on throttle, but progressing to digital trim on throttle.
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