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Seidel 7-70 radial: Help me decide!

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Old 12-09-2012, 06:55 AM
  #751  
Spuetz
 
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Default RE: Seidel 7-70 radial: Help me decide!

Hello Don,

i have never started a Seidel with an electric starter! Doesn't matter with our without collector ring. And I have nev had it run backwards either! Hurts me to crank it over with external brute force...
As for your starting problems: Seidels do need a lot of priming. I have never had one flood before. But I have cranked quite a bit with no response and the reason always was too little priming. Might it be that you spray fuel into the carb but don't actually let it get to the cylinders?
Here's what I do: I open up the throttle then I fuel up and towards the end when the tank is almost full, I squeeze the breather line shut while turning the prop over rather rapidly and for about 10 turns or more. That way fuel is sprayed into the carb by over-pressurizing the tank and sucked into the cylinders by the cranking. Works every time. If done enough, engine starts on first, lazy throw of the prop.
I do this because in my Aero I cannot reach the carburetor without taking the cowling off. So I can't spray any fuel in it or hold is closed with a finger.
However, what pull up now says is good advice. If you can get to the carb, the easiest is to hold it closed with a finger while throttle is full open and crank the engine over a couple of times. More than you think...

cheers, Martin from cold cold Germany...
Old 12-09-2012, 07:05 AM
  #752  
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Default RE: Seidel 7-70 radial: Help me decide!

I'll give all those suggestions a try next time. I did attempt to prime by squirting a small amount of fuel into the carb with a plastic pipette...but really quite a small amount. And I tried the finger over the carb thing (and the finger came away wet). But maybe I need to get much more fuel in the crankcase and into the cylinders. I'll try pinching the breather and drawing fuel in by rotating the prop.

The first time I ever started my Seidel it also started very easy with just one or two casual flips of the prop. That's why it's so frustrating now. I certainly don't like the idea of using an electric starter.

Spuetz, what's the needle valve setting on your Seidel? To start off, I'm using the usual 3-turns-out. By the way, with the KELEO collector ring in place access to the needle valve is really limited.
Old 12-09-2012, 07:23 AM
  #753  
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Default RE: Seidel 7-70 radial: Help me decide!

Don, blow into the fuel tank breather tube like Spuetz suggested. That will get lots of prine full into the carb. I do the same thing with my Laser 300 because I can't access the carb with the cowl on. Also fyi, Laser suggests that the breather line be pointing into the air stream, aka foward. This in fact makes a difference as I found out. You get a consistant amount of fuel pressure. Perhaps the Seidel is the same way.

One of my buds has his Horizon USM 7-77 running in a Bryon Corsair. Weight 30#. His engine runs great and flys the plane very well. He's using the collector ring from Horizon Hobby. According to him he was told that the engine runs better with the muffler pressure provided by the collerctor ring, just an fyil
Maybe Spuetz could comment on that...
Old 12-09-2012, 07:32 AM
  #754  
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: BobH
Don, blow into the fuel tank breather tube like Spuetz suggested. That will get lots of prine full into the carb. I do the same thing with my Laser 300 because I can't access the carb with the cowl on.
Sounds like a good trick for priming in the final model. Speutz has also mentioned earlier that he has built in a small bent tube to one of his models to allow priming from outside.

Also fyi, Laser suggests that the breather line be pointing into the air stream, aka foward. This in fact makes a difference as I found out. You get a consistant amount of fuel pressure. Perhaps the Seidel is the same way.
The KELEO collector ring has a nipple for the "breather" line...just like regular mufflers.

I'll just keep trying. I know it's run before.
Old 12-09-2012, 09:21 AM
  #755  
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Default RE: Seidel 7-70 radial: Help me decide!

Don, the "breather line" from the muffler goes to the tank. It pressurizes the tank. I hope thats where you have it? The Vent line of the tank is the one that you point into the air stream. Just to claify any confusion here.
Old 12-09-2012, 09:38 AM
  #756  
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Default RE: Seidel 7-70 radial: Help me decide!

I have a friend with a Saito 5 cyl on a fleet biplane and he has a priming tube due to the carb being buried, it seems to work well as he hand starts it rasily and it has a collector ring on it. I start my ASP 400 with an electric starter for the first start of the day but its OK after that to hand start. Mostly!
Doc
Old 12-09-2012, 12:04 PM
  #757  
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: BobH
Don, the ''breather line'' from the muffler goes to the tank. It pressurizes the tank. I hope thats where you have it? The Vent line of the tank is the one that you point into the air stream. Just to claify any confusion here.
???

I've always used a 3-line system on all of my engines: 1) fuel-fill line (capped with a fuel dot), 2) a fuel line from the tank to the carb, and 3) a vent line from the "air pocket" inside the tank to the muffler nipple. Are you saying that there should also be a FOURTH connection to the tank? I've never heard of that.

Of course, all 4-stroke engines also have a "breather" nipple on the crankcase, which is open to the air...but you're not talking about that, are you. (And there isn't one of the Seidel anyway.)
Old 12-09-2012, 02:51 PM
  #758  
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Default RE: Seidel 7-70 radial: Help me decide!

I think y'all got your signals crossed and you're both talking about a three line systen just as you described Don.
Doc
Old 12-09-2012, 03:17 PM
  #759  
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Default RE: Seidel 7-70 radial: Help me decide!

Don you have the set up I was thinkink you have. Your fuel line set up seems to be fine.
Old 12-09-2012, 10:30 PM
  #760  
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Default RE: Seidel 7-70 radial: Help me decide!

Third day, no success, no progress. Nothing. At this point I have:

1. Reset the Microsens glow system 3 times confirming that glow power is going to three different plugs as it should. The system seems to be functioning as it should. But I may have to cut the glow system out of the loop for the time being until I can get the engine running. [:@] So it's back to the problem of how to light the candles.

2. Disconnected and emptied the fuel line, reconnected and checked that fuel is being pulled in. (yep)

3. Tried all different ways to "fully prime" the engine (finger over carb, pinching the vent line, injecting fuel directly with a pipette. The carb feels wet and there was even some fuel dripping out of the collector...but no hydrolock on cylinder movement.

4. Tried the throttle needle at 2, 3, and 4 turns out.

I try starting with an electric starter but even with a fresh 12V car battery my normal size starter can't turn the Seidel's prop.

So I really am back to square one and I don't see anyplace else to go. Guess, I need to start all over again. Maybe even remove the collector ring. Basically get it back to the point that it was in when it last ran (no collector ring + a simple 2V lead battery).

Old 12-09-2012, 11:26 PM
  #761  
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Default RE: Seidel 7-70 radial: Help me decide!

Squirt fuel in the top 3-4 cylinders, flip the engine 2-3 times and put the glow on. If it does not pop after 4-5 flips the glow driver is not getting the amps. No need to take the ring off.
Old 12-10-2012, 12:21 AM
  #762  
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: TFF
Squirt fuel in the top 3-4 cylinders...
How would I squirt fuel into the cylinders?

Logically, I guess it has to be one of two things: 1) the fuel isn't getting to where it needs to be or 2) the glow power isn't igniting the fuel. There aren't too many possible problems left in terms of #1 and if #2 is the problem then we're basically saying that what is supposed to be the best glow system available, doesn't work.

I feel like I need to cut the glow system out of the equation to find the problem. Could I connect the glow plug cables "directly" to my 3.7V 5000mAh LiPo? That is, the seven red glow cables connected (somehow) to the positive (female) banana-plug terminal on the battery and the black negative/ground cable to the minus terminal.

Another question: Would I get some sort of ignition even if just one or two of cylinders were firing?
Old 12-10-2012, 01:40 AM
  #763  
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Default RE: Seidel 7-70 radial: Help me decide!

Also...what does it mean to say "the glow driver is not getting the amps?" I mean, if the glow plug glows (a nice red hot) doesn't that mean it's got enough power to ignite the fuel?

(BTW, I hate to think about this, but I had a similar problem with my RCV91cd and the problem went away when I ordered a replacement carb.)
Old 12-10-2012, 04:02 AM
  #764  
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Default RE: Seidel 7-70 radial: Help me decide!

Hi Don,

I must say I am at a loss here. The glow action you describe is definitely sufficient what with the plugs glowing visibly pink.
So it must be the fuel.
My carb needleis opened exactly two full turns.
As for the fuel system - to clear-up the misunderstandings: The "breather line" is the same as the "vent" - just a different name, I guess. So I have the normal setup: one line for fueling, one vent and one to the carb. The one for fuelingI have attached to a self-closing fuel valve. The vent connects to a pressure nipple on my self-built collector ring. What I do is that I pinch the vent line shut WHILE I am fuelling with an electric fuel pump. That way the tanks gets over-pressured. No air can leave the tank because the vent line is shut. This way fuel is pressed into the carb. In any case I have found that putting fuel into the carb is not enough - however you do it - with a syringe or by blowing into the vent or with my method. You also MUST turn over the prop WHILEputting the fuel into the carb, so the fuel gets sucked into the cylinders.

Exchanging the carb? Well, I don't think that that would be necessary.

How much it the throttle open when you try to start the engine? I have had problems startin the engine because Ihad trimmed the throttle to a very low idle rpm (below 1000 rpm) during the last flight. Now when Itried to start again, it was just too much closed.... In that case either bring the trim forward or just advance the throttle a couple of clicks. It won't start if not open enough.

Cheers, Martin
Old 12-10-2012, 04:34 AM
  #765  
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Default RE: Seidel 7-70 radial: Help me decide!

I'm using a hand pump for fueling so the two procedures I tried were:

1) putting a finger over the carb opening (with it wide open) and rotating the prop (quickly) ten times or so. This seems to be drawing in fuel and I'm seeing some drip out of the collector ring and the bottom cylinder rockers are wet.

2) filling the tank, then pitching off the vent line while rotating the prop. I suspect that injecting the fuel with the pipette wasn't doing anything.

After priming in these ways, the next step was to connect the LiPo to the glow system, switch on the Tx then Rx, then quickly move the throttle from idle to full to idle to "arm" the glow system (showing a flashing red light for Start Mode). Then I advanced the throttle until I could visually see that the carb was about 1/4 open (to 1/3 open), confirmed that the SM status light was still flashing red (it automatically shuts off after 90sec. for safety reasons)...and if all of this is good to go, try flipping the prop.
Old 12-10-2012, 06:08 AM
  #766  
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Default RE: Seidel 7-70 radial: Help me decide!

Ready to try again.

I have checked every aspect of the fuel tank and lines. Everything checks out OK. I have checked that each of the seven glow plugs is working with a standard glow starter. All are OK. I've redone the throttle servo setup both mechanically on the test stand and on the Tx. It's now set to 1/4 open with the stick at idle, with the trim a couple of ticks above neutral. When I drop the trim all the way to the bottom, the carb is completely closed. So that's OK. I've reset the Automatic Programming Mode on the Microsens GLOW-LP7 and BALANCER glow system. A check with one glow plug unscrewed shows that it operates as per the instructions providing a good strong glow with the throttle stick in the Start Mode position (from idle up to about half). So that seems OK. And finally, I mixed a fresh batch of 92% methanol + 8% synthetic oil. The needle valve is set at an initial position of 2 turns out.
Old 12-10-2012, 06:11 AM
  #767  
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Default RE: Seidel 7-70 radial: Help me decide!

...
Old 12-10-2012, 07:32 AM
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Default RE: Seidel 7-70 radial: Help me decide!

...
Old 12-12-2012, 05:46 AM
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Default RE: Seidel 7-70 radial: Help me decide!

12-12-12

WAHOO!!!

I'm not sure exactly what made the difference today but it started! I primed it the first time by injecting about 30cc of fuel directly into the carb with a pipette while rotating the prop quickly. It still didn't start immediately but it was beginning to turn over a couple of revolutions. Then eventually, on maybe the 10th flip, it started up. I let it run for about 3-4 minutes at idle and then shut it off by adjusting the T-cut on the Tx. Subsequent to this first somewhat hesitant start, I started the engine perhaps a half dozen more times and each time the engine required no priming and started up on the very first casual flip. Just switch on the Tx and Rx, "arm" the Microsens system by quickly moving the throttle to full then back to idle, and then flip the prop. [8D] With the glow power on, it idles very easily and reliably at 1700rpm, and probably even lower.

There are still some adjustment issues to work out. For one, the glow system stays on too long, from idle at 1700rpm all the way up to 4500rpm (which is about 7/8th of the throttle movement). I need to reset this so that it cuts off at maybe around 2500-3000rpm. Second, once the glow system does cut off (as shown by the status light turning green) the engine sags from 4600rpm to 3400rpm and then dies. This is probably a simple needle valve adjustment. I didn't have to time to work on this because it was starting to rain.

Nevertheless, a satisfying outcome!
Old 12-12-2012, 07:27 AM
  #770  
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Default RE: Seidel 7-70 radial: Help me decide!

So what was that "pop" you described in your previous post? Was it a blown glow plug? Did you check all the glow plugs after that happened? Glad it's running now. Guess the basic problem was the initiation procedure on the microsense?
Old 12-12-2012, 07:39 AM
  #771  
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Default RE: Seidel 7-70 radial: Help me decide!

I think the "pop" and the puff of smoke was a bit of fuel left on the outside of the cylinder that happened to be close to the plug when I did the system check. To do the check the body of the plug has to be touching the engine to light the plug. And, yeah, after that happened I checked all the plugs one by one with a standard glow starter and all of them checked out.

My best guess is that the problem was with the priming and the fact that the engine hadn't been run in nearly a year.
Old 12-12-2012, 08:10 AM
  #772  
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Default RE: Seidel 7-70 radial: Help me decide!

I have found I have to really prime these engines to get them to start. I use a hand-crank to fill the plane. Then I clamp off the line going to the tank and do about 6 1/2 turn "Cranks" of the pump to prime the engine. This works out about perfect to where the engine will fire up on the first flip every-time (as long as the glow-system is working). It needs to run at a high idle (about 2000rpm) for a few minutes for all the cylinders to come on line though
Old 12-12-2012, 06:01 PM
  #773  
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Default RE: Seidel 7-70 radial: Help me decide!

The challenge is working out a priming procedure that's going to work on some particular finished scale model. In most cases the "breather/vent/pressure" line is going to be inaccessible. It certainly would be in the case of my Sopwith Strutter. The carb is also going to be inaccessible. So in most cases that leaves the fuel-in line. By the way, my normal fueling procedure on my other models is to crank in the fuel until it runs out the muffler. That's a bit wasteful of fuel but it always works. Then I hand wind the prop 4-5 times to make sure the cylnders aren't locked and to get the fuel pumping around (you can hear it).

But I hate to think of filling up the Seidel and its collector ring to that extent!
Old 12-12-2012, 06:19 PM
  #774  
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Default RE: Seidel 7-70 radial: Help me decide!

I dont run a pressure line off the collector ring, i just run a vent line to free air.

Doing it that way, you could fill the tank via the fill line,
Then hook up the fuel jug to the vent line. Crank in some fuel via vent line, turn the prop a few times, then repeat.

Putting fuel in the vent line will force fuel to the carb, essentially priming the engine.
Old 12-12-2012, 07:44 PM
  #775  
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Default RE: Seidel 7-70 radial: Help me decide!

I suppose it would be possible to put a T-connector in the vent line to accomplish this. Personally, I've always used a pressurized tank on all my models.


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