abufletcher

We just had a little break in the weather...and nothing. That's definitely disappointing, but is there a silver-lining? At least now I know with 100% certainty that it is NOT a glow problem...and probably not a problem with the Microsens system either. It has GOT to be a fuel problem of some kind. But what could it be??? I've tried a different tank, different tubing, different needle valve settings, and different priming procedures. What's left?

jjscott

Is there any practical way to directly inject a shot of fuel (preferably starter fluid) into the cylinders? Close the needle valve, take out the plugs and turn over enough to ensure the cylinders are clear of fuel. Then put a couple of drops of fuel into the top two or three cylinders, install those plugs, lite the plugs and turn slowly over by hand. See if you get any kick back at all. Ether starting fluid would be best if it available in Japan.

I haven't read this thread in detail, but I'm sure you've confirmed the valve timing is OK and you've got compression. With the plugs out you should be able to determine prop position for compression on the top cylinders you want to test. Didn't some of the old rotaries require a direct prime to get going? Assuming the engine is OK mechanically, it is either getting too much fuel or too little. Keep moving the direct prime amount up until you get the kick back or bump. Then you'll know how much the engine likes to run.

Jim

abufletcher

I tried a few drops of the regular fuel into the top cylinder earlier and didn't get anything. But it's worth trying again with the top three cylinders. What is 'starter fluid?"

I haven't done this because I would have no idea how to do it. I also wonder how the valve timing could have "changed" during the time the engine sat around. Also my engine has always had very little compression (which is apparently typical of all Seidel engines). There's no such thing as counter-rotating up to compression as you might do on a single cylinder 4S.

So would the position from which I start the flip have any possible effect? That seems crazy...but at this point, I'm willing to consider crazy.

Yes, indeed. Most of them required priming. The aircraft with full cowls, like the Sopwiths, had slots in the cowl to allow the priming.

Again, I ask myself, how could it NOT be?

That seems like the only conclusion. I'll experiment a bit more with priming procedures but I'm not optimistic. What to you mean by a kick back or bump? Do you mean some indication that it's firing?

abufletcher

How about this: What if I were to completely close the needle valve, remove all the plugs so that any fuel could drain out, reinstall all but the top three plugs, put in a few drops of fuel into each of those cylinders, put the plugs back in and try to start? What should happen? Should I at least get a pop or two from those cylinders? And If I didn't what would that tell me?

abufletcher

OK, here's something. I was just rereading the German-language version of the Seidel manual which is more detailed than the English version. It states that the initial needle setting should be 3 to 4 full turns out. I've been trying at about 2 to 2 1/2 turns (which Spuetz has said works for him). I'll try it at 4 turns out.

When all else fails: Lesen Sie das verfickte Handbuch.

RBACONS

My Feedback: (3)

Stupid question but how certain are you that your throttle servo is moving in the correct direction? With moving the engine around between planes and test stand, is there any chance the movement is reversed?

jjscott

I agree that the engine should not have mysteriously gotten out of time by just sitting. Since it's dead all possibilities should be considered, even the improbable ones.

Starting fluid is ether (or substitute) in a spray can and available in the US from auto parts suppliers. Pharmacies used to sell small bottles of medical grade ether but don't any longer. Japan??? Shot directly into a cylinder or carb intake ether's high volatility is usually enough to make the engine fire.

Can you remove a top valve cover to see the valve action on that cylinder? The intake valve opens as the piston goes down (look in the hole). The intake closes and then when the piston nears top dead center the mixture ignites. The prop position at that point is what you want. Back up the prop to where the piston is back fully down and intake closed. Shoot some ether in the hole, install the plug, add the battery and pull over. You should feel a little bump as the prop tries to kick back when the mixture ignites. If nothing happens use a little more ether and try again. If the engine won't turn there's too much fuel and the cylinder is flooded. Now, this works OK on a single cylinder engine but may be much harder to tell what's going on with the radial.

In the ideal situation getting a firing indication on several cylinders would be ideal. You'd need the firing order to try that. If your thumb will cover the plug hole try turning the prop until the compression pushes your thumb away. That's the point to shoot in the ether (before the piston hits the top).

To clear the engine the plugs need to be out and the throttle open. Then turn over about ten times or so. That should clear it out. With only one or two cylinders connected the engine won't run. The idea is to see if those cylinders fire using the starting fluid as fuel. That can be determined by pulling the prop through by hand through the firing point and feeling the "bump". Just pull through slowly and feel for the reaction. If the single cylinder fires, fuel and spark to the remainder should mean they will all fire. Getting the right amount of fuel through the carb is another matter, but at least you've confirmed the thing should run.

The D cells eliminate any ignition issues. The starting fluid eliminates (almost) any mechanical or timing issues. Then the task is to alter the amount of fuel so it runs. There are no air leaks in the carb mounting like a dried out or cracked O ring?

abufletcher

On the stand, I can visually inspect the carb opening. So no problem there.

abufletcher

Tried starting with the needle 4 and 3 turns out. Nope. I tried a light prime and a heavy prime. Nope.

RBACONS

My Feedback: (3)

At the moment, I'm at a loss as to what to suggest. Almost anything else might keep the engine from running well but I'm not sure it should keep it from popping after priming or trying to start. Do you have a starter that you can use instead of hand flipping the prop? It will at least give the engine a better chance of starting and you can see if its pulling fuel well because it will start dripping out. Things like the valves being out of shim, or a stuck valve would likely not affect all cylinders. Possibly a horrendous air leak but again, I think you should at least get a pop from the priming.

abufletcher

My regular starter on my usual 12V car battery doesn't have enough umph to crank the UMS 770. It'll just barely push it around.

I'm also at a complete loss.

abufletcher

Here (mostly for my own information) are the translated instructions for starting the motor (p.11):

STARTING YOUR RADIAL ENGINE

Attention:

Before every new start the engine must be rotated about 3-4 times clockwise, that is, against the run direction.
In the event of binding, please don't use any force, rather the two lower plugs should be removed to allow the oil to drip out.

The Starting Procedure

1. Ignition OFF (detach the power cable).

2. Fill the tank with fuel.

3. Fully open the carburetor's throttle valve.

4. Squirt a little fuel in the carburetor or close off the carburetor with a finger.

5. Turn the propeller through 3-4 times in the run direction (counter-clockwise). In doing so, unburnt mixture should (must) come out of the exhaust tubes.

6. Put the throttle valve back to the idle position.

7. Ignition ON (attach the power cable).

8. Flip the propeller by hand or with an electric starter.

The engine must now start.

After starting the engine leave the power to the plugs on for 10-15 seconds, then disconnect the power.

abufletcher

Warning regarding use of an exhaust ring (p.17):

Starting an engine which is equipped with an exhaust ring should only be done with an electric starter.

WHY?

If during a hand start, the engine sucks fuel and that fuel mixture collects in the ring, the danger exists that the engine with start and run backwards. The engine will then immediately run at the highest RPM and can't be throttled down. This uncontrollable situation can lead to dangerous injury.

geezeraviation

My Feedback: (3)

This is what you need, it's a Sullivan Dyna Tron, operates on 12 or 24 volts, may turn your engine over with out the Miller belt reduction unit, but certainly will with it. Cranks my DA 100 with ease. I think the reduction ratio is 4 to 1. Not cheap, but when you need the job done......priceless.

Fits nicely in this little tote which contains 2 ea 7 amp gel cell hobby batteries. Pity you're not in Houston, I'd tell you to come over and we'd start your engine.
Doc

RBACONS

My Feedback: (3)

Well, since you've tried everything else, might as well trying starting it without the collector ring on it. I use a home-made ring cobbled together from brass tubing so I don't really know why yours should be a problem but you never know. Be forewarned that without the ring, the Seidel will spit oil everywhere.

abufletcher

Doc, I'd sure hate to spend $100 bucks (plus shipping) for a starter I would ONLY use with this engine and which might not even solve the problem.

I considered that but even the thought of removing the exhaust ring sends chills down my spine. It was a real struggle to get it on (involving loosening all the cylinders from the crankcase) and battling to get all the pipes to seat (which they do eventually). Anyway, most of the run-time I have on the engine is with the collector ring.

The first couple of times I ran it was without the ring and it was actually surprisingly clean. But I just couldn't stand the bubble-blowing sound it made. At this point, there's only 5% oil in the fuel anyway.

abufletcher

There's an older guy (mid 80s) at the club, who owns a small RC shop near the field. And he has one of the Evolution 7-35 engines in the shop. He has started it but never flow it in anything. He mentioned once that he could procure any fuel I needed. He seems like just a sweet old guy but then you remember that we all go through stages of our RC life. Previously he owned and flew in competitions six 1/6 scale turbine scale jets. Anyway, he might be able to help.

geezeraviation

My Feedback: (3)

5% seems low but I'm sure you're running what Seidel recommends.
Doc

sjhanc

My Feedback: (3)

A club member in my old club bought a radial engine and a military bi-plane trainer ARF from Horizon Hobbies last year and got a very nice flying scale model that is a real crowd pleaser.

abufletcher

Seidel recommends 8% max during the break-in phrase, then reducing the oil to a max of 5-6%.

abufletcher

I'm curious. What was it?

geezeraviation

My Feedback: (3)

My guess it was a Sterarman

abufletcher

Since I can't think of anything new to try on the engine, I've been spending the last couple of days repairing my Sunday flyer ARF. After the frustration of not being able to start the Seidel, I figured some fun-in-the-sky was called for. So I drove the hour through the mountains to the field, set it up, and started the engine. A club mate wanted to help by carrying the model out to flight line. Well, he tripped and while he did a good job of avoiding falling into the spinning propeller he did come down on the stab and rudder. So that was it for the day. Even though he is an experienced flyer, I really prefer than no one touches my model, for example, to "hold it down" during a start. i know exactly where to hold each of my models. Others don't.

Fairly simple repairs (remove the old coverings, replace the LE and TE on the rudder and stab, sand, slot for new hinges, recover, add bracing wires, remount the hardware, etc.) but it all takes time. Anyway it was due for an overhaul. I don't think I've worked with balsa for over a year!

RBACONS

My Feedback: (3)

Abu,

Earlier you posted:

I haven't used this fuel with any other 4-stroke because it's pure methonol. To use it with a regular 4S I'd need to add 15% oil and nitro (which I don't have and can't get). But it does burn in a dish. The small squealing sound is only when I have a plug out (and pressed against the metal of the engine) for a glow test.

It sounds like you are running 0% nitro. My buddy and I have our Seidel fuel custom-blended by Power Master (now VP Racing). It is 12% Nitro and 7% synthetic oil. 0% nitro is usually for high compression engines which the Seidel is certainly not. Can you get a tankful of some normal 4 stroke fuel and try it? Doesn't have to be exact. Any 10% or 15% nitro fuel should work for a test.

RBACONS

My Feedback: (3)

Also, I assume you are using OS-F plugs. Those are good 4-stroke plugs but not good plugs for low-to-no nitro. I think you may have a fuel/plug compatibility issue. Plug is not "hot" enough to fire the 0% nitro fuel.