170 cdi Help
#1
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170 cdi Help
Ok, I need some help to setup a 170cdi. No its not my motor, but a friends honest!
It has an 18x10 mezjlik on it, running CP 30% heli fuel. Top end is nice and smooth about 8300 rpm (probably can prop up a bit), idle is good will sit nicely all day at 1700 ish (maybe lower didn't check). At about 50% through it hesitates, if you work the throttle a bit it will move past that point and continue fine on up to full throttle. Its not so much a burble, but more a misfire? We fiddled a little with the pump, and high speed to no real avail. Seems when the motor is cold it doesn't happen, but after it warms up a bit then it starts. HS needle is around 1.25 out, its very responsive, easy to hear peak and easy to set.
Since its running so nice at full and idle I didn't want to play with it too much, as it seems to me to be more ignition related? Ignition is being ran directly from Rx power. Last glow I ran was a 160dz, and that was a few years ago, so I am getting out of my element! lol
Thanks!
It has an 18x10 mezjlik on it, running CP 30% heli fuel. Top end is nice and smooth about 8300 rpm (probably can prop up a bit), idle is good will sit nicely all day at 1700 ish (maybe lower didn't check). At about 50% through it hesitates, if you work the throttle a bit it will move past that point and continue fine on up to full throttle. Its not so much a burble, but more a misfire? We fiddled a little with the pump, and high speed to no real avail. Seems when the motor is cold it doesn't happen, but after it warms up a bit then it starts. HS needle is around 1.25 out, its very responsive, easy to hear peak and easy to set.
Since its running so nice at full and idle I didn't want to play with it too much, as it seems to me to be more ignition related? Ignition is being ran directly from Rx power. Last glow I ran was a 160dz, and that was a few years ago, so I am getting out of my element! lol
Thanks!
#2
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RE: 170 cdi Help
Cann 773
Not near enough Prop. try 19x11. High Speed Needle is probably to rich depending on how much time is on engine. My needle settings near sea level are 7/8 to 1 out on high speed needle and flush on low speed. There are two other threads I started this month on the 170 DZ CDI that have got a lot of great information in them from many others.
Good Luck.
Dick
Not near enough Prop. try 19x11. High Speed Needle is probably to rich depending on how much time is on engine. My needle settings near sea level are 7/8 to 1 out on high speed needle and flush on low speed. There are two other threads I started this month on the 170 DZ CDI that have got a lot of great information in them from many others.
Good Luck.
Dick
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RE: 170 cdi Help
chad
check ur plug gap .35mm-.45mm also run a 19x 11 apc. I would set the plug gap at the .35 in some cases the gap does open up a bit and cause the motor to run rough in transition
in more extreme cases they act like its running lean and even spit the prop misfiring very badly . A carboned up plug will also act like this.
gary
check ur plug gap .35mm-.45mm also run a 19x 11 apc. I would set the plug gap at the .35 in some cases the gap does open up a bit and cause the motor to run rough in transition
in more extreme cases they act like its running lean and even spit the prop misfiring very badly . A carboned up plug will also act like this.
gary
#6
RE: 170 cdi Help
Chad,
Is the engine new? The new ones might do that misfire once in a while, try also with a separate battery, at least to test it, if the battery can not keep a stable voltage it will do that, I tried a TP 480mAh and it did that on the third flight.
Adjust to peak and back of 200-300RPM, that's where I set my engines all the time and works great.
Is it smoking to much on the transitions? if so you can close 1/8 (manual says 1/4) counter clockwise to lean the transition.
Also the previous advise are good to check, remember to check the valves clearance.
Regards
Is the engine new? The new ones might do that misfire once in a while, try also with a separate battery, at least to test it, if the battery can not keep a stable voltage it will do that, I tried a TP 480mAh and it did that on the third flight.
Adjust to peak and back of 200-300RPM, that's where I set my engines all the time and works great.
Is it smoking to much on the transitions? if so you can close 1/8 (manual says 1/4) counter clockwise to lean the transition.
Also the previous advise are good to check, remember to check the valves clearance.
Regards
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RE: 170 cdi Help
It's a prop thing, definitely. I had that with my CDi running 18,1x11 APC.
I managed to lean out most of it by turning the regulator clockwise about half a turn but it sometimes sounds like it's misfiring going up past midrange. I'm not able to use 19x11 on grass due to low prop clearance.
I managed to lean out most of it by turning the regulator clockwise about half a turn but it sometimes sounds like it's misfiring going up past midrange. I'm not able to use 19x11 on grass due to low prop clearance.
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RE: 170 cdi Help
I'm trying to get a new 170 that I added CDI run in.
First run, 30%CP, 17-12, 2 turns out and 3K...normal rich run.
Second run pretty similar but started surging half way through the tank so I stopped it and richened the punp 1/2 turn. Re-started and it ran very well.
Third tank started very well, consistent run until 1/3 through the tank and then it quit without warning (no bang or surging just stopped) and would not re-start. I noticed that there was no fuel in the line up to the injector although there was fuel up to the pump. Even if I open the throttle to full and turn the prop over by hand no fuel seemed to be getting to injector.
Now...this was the first 170 I added CDI to, could I have screwed something up? What should I check first?
Colin.
First run, 30%CP, 17-12, 2 turns out and 3K...normal rich run.
Second run pretty similar but started surging half way through the tank so I stopped it and richened the punp 1/2 turn. Re-started and it ran very well.
Third tank started very well, consistent run until 1/3 through the tank and then it quit without warning (no bang or surging just stopped) and would not re-start. I noticed that there was no fuel in the line up to the injector although there was fuel up to the pump. Even if I open the throttle to full and turn the prop over by hand no fuel seemed to be getting to injector.
Now...this was the first 170 I added CDI to, could I have screwed something up? What should I check first?
Colin.
#9
RE: 170 cdi Help
Seems like you have an air bubble in the pump, just try to force some fuel by squeezing the tank or by using a syringe from the injector hose, check you don't have any damaged hose(pin holes), it's typical in new engines, once you prime the pump well it should not happen again, unless you run out of fuel.
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RE: 170 cdi Help
Take the rocker cover off and check the intake pushrod is going up and down as this is what drives the pump.
Disconnect the pump from the "carb" and see if it pumps then if it does, then the blockage is in the carb, if it still doesn't then something isn't right with the pump. Bypass spring may be broken or pump valves may have crud in them
Very carefully pull the pump apart and check the valves don't have any bits of stuff in them. Take your time, don't break any gaskets or diaphrams and enjoy learning the mechanics of the engine.
My 170 has a funny characteristic where it feels like either an intake or exhaust valve (or both) doesn't completely close when turning it over by hand sometimes as you can't find the compression stroke. Valve clearances are correct, has one hour (8 flights) on the clock and runs like a swiss watch with 15%nitro 20%coolpower and 16x14 APC (in a sport airframe for running in) pulls 8k +- 50rpm on the ground and 2k tickover.
Disconnect the pump from the "carb" and see if it pumps then if it does, then the blockage is in the carb, if it still doesn't then something isn't right with the pump. Bypass spring may be broken or pump valves may have crud in them
Very carefully pull the pump apart and check the valves don't have any bits of stuff in them. Take your time, don't break any gaskets or diaphrams and enjoy learning the mechanics of the engine.
My 170 has a funny characteristic where it feels like either an intake or exhaust valve (or both) doesn't completely close when turning it over by hand sometimes as you can't find the compression stroke. Valve clearances are correct, has one hour (8 flights) on the clock and runs like a swiss watch with 15%nitro 20%coolpower and 16x14 APC (in a sport airframe for running in) pulls 8k +- 50rpm on the ground and 2k tickover.
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RE: 170 cdi Help
I found a bit of swarf under the pump diaphram...did'nt appear to peirce it so I just cleaned it up and reassembled the pump.
I put two more tanks through it yesterday with no issues.
Thanks for the advice.
Colin.
I put two more tanks through it yesterday with no issues.
Thanks for the advice.
Colin.