I have a moki 2.10.

I would like to run either a cline regulator or a perry pump so that I can have a reliable idle to full throttle without the fear of dead stick due to changes in rich/lean mixture during the fligt.

I am having a dificult time deciding which to use. I need the advise of some experienced modelers.

Thanks,

MR G

The perry does not work well for this. The pressure will vary and sooner or later be too great and cause irratic running.

You need to run crankcase pressure to your tank and a Cline regulator at your needle valve.

W8YE has it right.
Full muffler pressure, check valve and put the tank anywhere you want it.

I've run this set up for some time--------one thing you do need to consider if you use a three line tank set up.
The 'fill' line is under pressure too and unless you have a good plug (not merely a 4-40 screw) you will find that it will depart and the fuel too!
Since it is all under pressure it doesn't take long to empty the tank--------trust me I know of what I speak!!!

Yes I landed without incident---------startling to have a flame out when that hasn't happened in years.

I would like to ask you fellas a question out of simple ignorance (in that I've never used a Cline).

I have used many pumped & regulated YS four-strokes, which seem to operate on the same principle as the Cline, as I understand them. They work great, never failed me. But as you say, you have to keep an eye on your filler dot, or whatever you use, and be sure you relieve the tank pressure as soon as you get back in the pits after a flight. You also have to keep your check valve clean, make sure it doesn't get stuck with dried out fuel or whatever. I've heard rumors of ruptured tanks, but never had one myself, nor seen one at fields full of YS engines.

I've used Perry pumps to fix two-stroke installations with fuel pressure problems, and never had the deadstick problem or anything I could attribute to varying tank pressure. When I've run out a tank on the ground, I always get a steady rpm right up to the end, and then an instant shutdown, no running lean for the last few seconds. Maybe this is because I favor the so-called Bypass method of plumbing, where the pressure from the pump is in effect regulated at the fuel nipple by the alternate route for excess fuel back to the tank. It seems to me that with this plumbing, the engine is drawing fuel much like a hose sucking from a running stream, just the suction from the venturi drawing the fuel, no excess or variable pressure from the pump affecting what gets drawn (not forced by pressure) into the engine.

I have a couple Clines sitting in a drawer, but never used one because the Perry has always worked for me. So my question is, do you have any direct experience with a bypassed Perry causing a deadstick? And if so, how did you determine that the Perry was the root of the problem?

I don't want to appear to be against the Cline, because my YS's work so well, but the Perry also works for me (at about half the cost of the Cline).

Cline all the way for me.

I don't like using muffler pressure for the Cline, as onewasp suggested. I prefer to tap the backplate and run full crankcase pressure to the tank.

Best thing to do is run 3 or 4 tanks through the engine on a stand or in the model WITHOUT the Cline installed. Give it a little break-in time first. Then install your Cline and tune it for perfect running.

The Cline is unforgiving if you do not know how or do not like tuning engines. You have to tweak the low end for absolute perfection, or it will constantly flood the engine--as it should. It's not hard, you just have to know how to properly adjust the low end and put the time into doing it.

When using a Cline-- the high end needle does not need to be adjusted quite as rich as a normally plumbed tank. With a normal glow engine setup--we tune rich on the high end to compensate for the lean condition as the tank runs out of fuel. This isn't necessary with the Cline because it will deliver the same fuel pressure to the carb down to the last drop. Just find peak RPM and back it up 3 or 4 clicks until it just starts to slow down a few RPM and go fly it.

Once you try a Cline--you'll never want to be without one again.[8D]

I have several. One is mounted on a TH .75 thats inverted. The tank is on the CG--about 12" behind the firewall. It runs flawlessly. It's like having the consistancy of a gas (walbro) carb on a glow engine. Tune it and forget about it. Go fly it and enjoy yourself without fretting over a deadstick.

I won't make any comments about the Perry pump other than to say--most of you already know how I feel about it.

The Perry seems to work satisfactorily on some engines, Say like a OS 160 but the Moki seems to do better with a Cline.

The personal problem I have with a Perry is that they will pass fuel when they are not being cycled.

A Perry pumping and a Cline doing the regulating down stream would be great.

I like the bypass system the best with a Perry. (For others) this is where you pump fuel to the needle valve with the Perry but there is a return line back to the tank. What you are doing with the Perry is assuring that there is fuel at the needle valve.

The Chain saws have a pump very much the same as the perry on one side of the carb and the other side there is a regulator identical to the Cline. They have worked very well for many years.

But with the Cline, all you need is a fuel head at the regulator and crank case pressure through a check valve is all that is needed.

The internal parts of a Cline originally came from a Walbro WL/WT style carb.

To make a walbro with pump and regulator into a glow carb feed system, look at http://home.wanadoo.nl/pereivers/reg...el_supply.html

This system can be loaded with exhaust pressure regulation, and gives excellent results curing the negative items of both perry and cline.

I too have never had a problem with a Perry pump. I have even used it sucessfully when the tank is high enough to cause fuel siphoning. I simply clamp the fuel intake line with a hemistat before filling, then when filled open the carb, open the hemistate for a second to prime the carb, then start, then quicly remove the hemistat. This is not possible with many cowled engines.

I use the hemistat for installations where the fuel tank does not siphon as well. In that case I do not add the hemistat till I prop the engine a few times to pump fuel into the carb. That is how I found that it works with tank levels that are too high. I did not even know the plane siphoned fuel till I didn't start it for a while after filling the tank, then noticed raw fuel unde the plane. I had flown it several times before noticing this. It did not siphon the fuel quickly and did not have time to flood the carb if started right away.

One concern I have is operating an engine made to operate from a muffler pressured tank and venturi carb and using the pressurized Cline or Perry. I tried to use a Cline system on an OS91FX(new engine). It would run, but not as good as when using muffler pressure with the tank right behind the engine. My tank was 12 inches aft of the engine and hence my desire to use the Cline system. I have read on RCU of many who are happy with the Cline. However, on my setup with the OS91FX, it appeared that the venturi type carb just didn't work as well. I finally have gone to a YS61(pumped two stroke) and it seems to run just fine. Just my 2 cents worth and my experience.

If the carburetor is good the Perry VP-30 works just great.