moki on crank pressure?
08-02-2005, 09:39 AM
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moki on crank pressure?
I have a moki 2.1 that I'm running with a cline regulator. The tank is up next to the motor so I don't have a fuel draw problem but I do have starting issues with the cline to the point that in competitions I go past my alloted time to get in the air. I'm going to remove the regulator but was curious if any one had run the crank pressure into the tank instead of muffler pressure. This would be much easier to convert and I wouldn't have to remove the motor to cork the backplate hole left from the pressure nipple. I'm guessing it's too much pressure into the tank but I thought I'd ask. Jim p.s., motor is inverted by the way and it's a scale airplane that I don't really want to risk flipping it over to start it.
08-02-2005, 10:06 AM
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RE: moki on crank pressure?
ORIGINAL: JIMMYTHEEAGLE
I have a moki 2.1 that I'm running with a cline regulator. The tank is up next to the motor so I don't have a fuel draw problem but I do have starting issues with the cline to the point that in competitions I go past my alloted time to get in the air. I'm going to remove the regulator but was curious if any one had run the crank pressure into the tank instead of muffler pressure. This would be much easier to convert and I wouldn't have to remove the motor to cork the backplate hole left from the pressure nipple. I'm guessing it's too much pressure into the tank but I thought I'd ask. Jim p.s., motor is inverted by the way and it's a scale airplane that I don't really want to risk flipping it over to start it.
I have a moki 2.1 that I'm running with a cline regulator. The tank is up next to the motor so I don't have a fuel draw problem but I do have starting issues with the cline to the point that in competitions I go past my alloted time to get in the air. I'm going to remove the regulator but was curious if any one had run the crank pressure into the tank instead of muffler pressure. This would be much easier to convert and I wouldn't have to remove the motor to cork the backplate hole left from the pressure nipple. I'm guessing it's too much pressure into the tank but I thought I'd ask. Jim p.s., motor is inverted by the way and it's a scale airplane that I don't really want to risk flipping it over to start it.
I really don't understand this question. Your description appears to ask whether pressurizing the tank with crankcase is better than muffler, but then you alude to the fact that you have to cork the backplate. This indicates you are using the crankcase pressure. If what you really are asking is if the muffler will provide sufficient tank pressure for the Cline system then the answer is NO.
If you read the Cline instructions properly, the crankcase tap is the normal source for tank pressure with a 2-stroke glow motor. You use muffler pressure from a 4-stroke. ****WARNING**** The crankcase pressure from a Moki (mine is the 180) is significant and will put a very solid positive pressure into the tank. When you are ready to defuel release the pressure first or you will see a stream of high-pressure fuel. The first time I did that the fuel came out of the tube in a stream that was almost 10' long.
From Cline: Fuel System
How it Works
The fuel tank is pressurized from 2 to 12 P.S.I. by a unique one-way check valve with the pressure from the crankcase of a two-cycle engine or from the exhaust of a four-cycle engine. This forces the fuel to the controller under that P.S.I.
The controller is mounted either beside or directly behind the engine. The carburetor’s fuel line suction acts on the diaphragm in the controller causing it to open the fuel valve in the controller. It is a demand controller; thus as the carburetor’s fuel line suction increases, the amount of fuel the controller passes increases. When the engine is stopped, no fuel can enter the carburetor.
How it Works
The fuel tank is pressurized from 2 to 12 P.S.I. by a unique one-way check valve with the pressure from the crankcase of a two-cycle engine or from the exhaust of a four-cycle engine. This forces the fuel to the controller under that P.S.I.
The controller is mounted either beside or directly behind the engine. The carburetor’s fuel line suction acts on the diaphragm in the controller causing it to open the fuel valve in the controller. It is a demand controller; thus as the carburetor’s fuel line suction increases, the amount of fuel the controller passes increases. When the engine is stopped, no fuel can enter the carburetor.
08-02-2005, 11:02 AM
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RE: moki on crank pressure?
I guess I didn't explain that very well did I. I'm trying to make life simple so I wanted to know if I could run the moki on crank pressure instead of muffler pressure not using the cline regulator. I have several moki's in sports plane flying with muffler pressure and no regulator and they perform just fine and in hindsight wished that I had set my scale plane up without a regulator. I thought in my scale plane though a regulator would be more reliable but I'm finding out that it's a pain to get started compared to how easy my non regulated moki's start in my other planes. To remove the regulator on my scale plane I have to pull the motor and mount and the batteries and all the nose weight I added so that I can get to the back of the motor backplate and remove the nipple and put in a bolt to plug the hole in the backplate. I'm sure that this is the safest and best for the reliability of the motor to plug the hole and go with muffler pressure as the motor was set up out of the box for but I'm just curious if the crank pressure is that much stronger than muffler pressure and would it make it impossible to lean the motor out enough or would it possibly even overinflate my tank. Thanks, Jim
08-02-2005, 05:02 PM
#5
RE: moki on crank pressure?
Are you sure it's not your starting technique that is the problem? They reason I say this is because I had to re-learn how to start my Moki's with the Cline. You first have to rotate the prop about a dozen times. This creates the pressure you need in the tank to get fuel to the carb for priming and starting. Otherwise the regulator won't supply proper fuel to the carb without pressure from the tank. So after you pressurize the tank just prime it as usual and mine starts the first flip every time.
There are many benefits to using the Cline even if your tank is right behind the engine.
-better fuel draw.
-more even mixture for consistant running
-uses less fuel, yes believe it.
-high G manuevers and verticals won't flame out
-the Moki loves it
There are many benefits to using the Cline even if your tank is right behind the engine.
-better fuel draw.
-more even mixture for consistant running
-uses less fuel, yes believe it.
-high G manuevers and verticals won't flame out
-the Moki loves it
08-02-2005, 05:17 PM
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RE: moki on crank pressure?
I had a cline regulator on a saito 150 where I mounted the tank on the cg with long fuel lines. The motor was mounted on it's side and I could close the throttle and put a starter on it for 20 or so revolutions. When I put the glow plug on and hit the starter, it would start every time. With the moki and the cline I'm holding my fingers over the exhaust outlets to try and draw fuel into the carb. I remove the glow plug and squirt a little fuel up into the head and flip it a few times and then reinstall the plug. It usually starts and runs for 3-4 seconds and then quits. I have to do this 3-4 times before I get the motor to draw fuel from the tank. I like the way it runs once it's running but it's taking far too long to start. Maybe I should expertiment a little more before I pull it. Putting a starter on it isn't doable since I have a painted spinner. Thanks for your help. Jim
08-02-2005, 07:43 PM
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RE: moki on crank pressure?
mokis like about 10 cc'c of fuel in the case to start easy so you should not have much of a problem starting it.i run an iron bay on mine and love it.like was said before turn it over till the tank builds pressure and open the throttle full for 3 or 4 more turns,hook up the glow wires and flip it backwards easy and it will fire first flick.when diong this be very careful when you hook up the glow plug as i have mine start all on ot's own with no flipping from me.i put an on off switch on my panel to help with this as it is very easy to get hurt
08-02-2005, 09:32 PM
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RE: moki on crank pressure?
Jim,
You don't need a starter. Just leave the glow driver off and spin the prop by hand about a dozen revolutions. You get the the hang of holding onto the tip of the prop and turning over the engine. You can also use two hands, one on each prop tip while you rotate it. After 12 rev's the tank is pressurized. Then prime it. Put the engine a click or two above idle and flick it backwards against compression. It starts every time, try it. You will see. I have the same exact setup.
The reason why it quits the first few times is because the tank is not up to maximum pressure yet.
Regards,
Joe
You don't need a starter. Just leave the glow driver off and spin the prop by hand about a dozen revolutions. You get the the hang of holding onto the tip of the prop and turning over the engine. You can also use two hands, one on each prop tip while you rotate it. After 12 rev's the tank is pressurized. Then prime it. Put the engine a click or two above idle and flick it backwards against compression. It starts every time, try it. You will see. I have the same exact setup.
The reason why it quits the first few times is because the tank is not up to maximum pressure yet.
Regards,
Joe
ORIGINAL: JIMMYTHEEAGLE
I had a cline regulator on a saito 150 where I mounted the tank on the cg with long fuel lines. The motor was mounted on it's side and I could close the throttle and put a starter on it for 20 or so revolutions. When I put the glow plug on and hit the starter, it would start every time. With the moki and the cline I'm holding my fingers over the exhaust outlets to try and draw fuel into the carb. I remove the glow plug and squirt a little fuel up into the head and flip it a few times and then reinstall the plug. It usually starts and runs for 3-4 seconds and then quits. I have to do this 3-4 times before I get the motor to draw fuel from the tank. I like the way it runs once it's running but it's taking far too long to start. Maybe I should expertiment a little more before I pull it. Putting a starter on it isn't doable since I have a painted spinner. Thanks for your help. Jim
I had a cline regulator on a saito 150 where I mounted the tank on the cg with long fuel lines. The motor was mounted on it's side and I could close the throttle and put a starter on it for 20 or so revolutions. When I put the glow plug on and hit the starter, it would start every time. With the moki and the cline I'm holding my fingers over the exhaust outlets to try and draw fuel into the carb. I remove the glow plug and squirt a little fuel up into the head and flip it a few times and then reinstall the plug. It usually starts and runs for 3-4 seconds and then quits. I have to do this 3-4 times before I get the motor to draw fuel from the tank. I like the way it runs once it's running but it's taking far too long to start. Maybe I should expertiment a little more before I pull it. Putting a starter on it isn't doable since I have a painted spinner. Thanks for your help. Jim
08-03-2005, 09:40 AM
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RE: moki on crank pressure?
I wrestled with taking it off or leaving it on all of last night. I decided to leave it on and I think I'll modify my holder to hold the plane in an inverted position if I need to as a last resort to start it that way. I did notice that with the cline I can see the fuel does get to the carb after I turn it over a dozen or more times. I think my issue is that I'm not getting it primed or I get it too primed and flood out the plug. I've tried to prime it two ways. One way is to remove the plug and try to squirt some fuel up in the cylinder which usually results in not a good enough prime. The other way is I work the fuel probe up into the intake by slowly turning the prop and I get too much fuel in the motor. I have to remove the glow plug several times and let the fuel run out during the starting procedure and blow out the plug before it fires. Then it usually runs after that if the fuel pressure in the take is sufficient. I'm just going to need to practice with an inverted motor until I get the right combination down. This is actually my fourth moki. My other three are mounted at 90 degrees in aerobatic planes and generally start on the 1st or 2nd flip back if you have the right amount of fuel in them. I'm able to shoot a little fuel in the carb and that usually does it. I believe it's more an issue of the motor being inverted than it is an issue of the cline regulator. Jim
08-03-2005, 10:39 AM
#10
RE: moki on crank pressure?
Oh ok. I did not know it was inverted. That's a whole different animal. Many people struggle with starting them inverted. I'm sure once the technique is mastered it's a piece of cake. Are you using the OS type F plug? They work better inverted. Also the low end should be adjusted right, not too rich or it loads up during idle.
ORIGINAL: JIMMYTHEEAGLE
I wrestled with taking it off or leaving it on all of last night. I decided to leave it on and I think I'll modify my holder to hold the plane in an inverted position if I need to as a last resort to start it that way. I did notice that with the cline I can see the fuel does get to the carb after I turn it over a dozen or more times. I think my issue is that I'm not getting it primed or I get it too primed and flood out the plug. I've tried to prime it two ways. One way is to remove the plug and try to squirt some fuel up in the cylinder which usually results in not a good enough prime. The other way is I work the fuel probe up into the intake by slowly turning the prop and I get too much fuel in the motor. I have to remove the glow plug several times and let the fuel run out during the starting procedure and blow out the plug before it fires. Then it usually runs after that if the fuel pressure in the take is sufficient. I'm just going to need to practice with an inverted motor until I get the right combination down. This is actually my fourth moki. My other three are mounted at 90 degrees in aerobatic planes and generally start on the 1st or 2nd flip back if you have the right amount of fuel in them. I'm able to shoot a little fuel in the carb and that usually does it. I believe it's more an issue of the motor being inverted than it is an issue of the cline regulator. Jim
I wrestled with taking it off or leaving it on all of last night. I decided to leave it on and I think I'll modify my holder to hold the plane in an inverted position if I need to as a last resort to start it that way. I did notice that with the cline I can see the fuel does get to the carb after I turn it over a dozen or more times. I think my issue is that I'm not getting it primed or I get it too primed and flood out the plug. I've tried to prime it two ways. One way is to remove the plug and try to squirt some fuel up in the cylinder which usually results in not a good enough prime. The other way is I work the fuel probe up into the intake by slowly turning the prop and I get too much fuel in the motor. I have to remove the glow plug several times and let the fuel run out during the starting procedure and blow out the plug before it fires. Then it usually runs after that if the fuel pressure in the take is sufficient. I'm just going to need to practice with an inverted motor until I get the right combination down. This is actually my fourth moki. My other three are mounted at 90 degrees in aerobatic planes and generally start on the 1st or 2nd flip back if you have the right amount of fuel in them. I'm able to shoot a little fuel in the carb and that usually does it. I believe it's more an issue of the motor being inverted than it is an issue of the cline regulator. Jim
08-03-2005, 11:26 AM
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RE: moki on crank pressure?
Yes, I've always used the f plug and replace them fairly frequently as they don't seem to last as long in a moki as they do in a 4 stroke. I always use large fuel tubing and I always drill out the clunk. The cline doesn't rely as much on the needle setting as the motor in the stock set-up. The other day when I put a tach on it I could turn the needle a full 3 1/2 turns with only a 700 rpm change. At the needle valves leanest setting before it loses rpm I'm at 7400 with a 3W prop that is 20x8 on 5% magnum fuel. The motor has 6, 8 minute flights and two tanks on the ground run through. I should be getting closer to 7800 but the motor is still new. With the regulator, throttle transition is excellent and I haven't changed the low idle setting. I do have an on board glow that kicks off at 2/3 throttle. Jim
08-05-2005, 01:01 AM
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RE: moki on crank pressure?
Here are a couple of tips to make your life a little easier. I have been running a cline quite awhile on an OS 1.60FX. I had the same starting issues at first but I modified my starting technique to take in account the pressure system. This setup is similar in setup to a YS engine. First off, there is not need to put your hand over the exhaust when starting. In this setup it will not prime the motor. This only works when using muffler pressure. Try this starting technique:
When you fuel the tank after it fills up plug the vent hose and let it run about 5 more seconds to build pressure in the tank for priming. You will have to pinch the fuel line when removing the fuel pump line and installing the fuel dot. You can also install a one way check valve between the tank and the fuel dot the hold in the pressure so you do not have to pinch the line. This takes care of the tank pressure for starting. Now open the carb fully and flip the prop through compression 10 times. Now try to start it. If it does not start then either use your fingers or get something and plug the carb opening while flipping the prop to prime the engine. This should get the engine running along as the engine is sound. When the engine starts slow work the throttle up till the engine develops enough pressure in the tank to supply the engine fully.
When you fuel the tank after it fills up plug the vent hose and let it run about 5 more seconds to build pressure in the tank for priming. You will have to pinch the fuel line when removing the fuel pump line and installing the fuel dot. You can also install a one way check valve between the tank and the fuel dot the hold in the pressure so you do not have to pinch the line. This takes care of the tank pressure for starting. Now open the carb fully and flip the prop through compression 10 times. Now try to start it. If it does not start then either use your fingers or get something and plug the carb opening while flipping the prop to prime the engine. This should get the engine running along as the engine is sound. When the engine starts slow work the throttle up till the engine develops enough pressure in the tank to supply the engine fully.
