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Trouble Starting MZ202 - shakirhussain - 06-21-2018

Hello all, I am trying to start a MZ202 (new engine with less than 1 hour). I got this after buying a used Mosquito on April. With the help of mechanic, after spending for about 1 hour, he started the engine and I was able to go till 5500 rpm. Then after that, I am not able to start it again.  I called the mechanic again, and he was not able to start again (he works on 2 stroke engines, but not a helicopter mechanic). After he left, I am trying to start MZ202 for a month now. All i can see is, the engine fires for a second and then stalls. There are some pop or misfires happening during the startup. When I try few times. 

Thanks to Mike Messex for answering my texts and  was very helpful in steering me through debugging steps and I learned a lot from him. Now i am picking up about the engines. I am also reading lot of documentation and videos. I have a electrical Engineering degree and brushing up knowledge I learned few years back in college.

Here is where I am now with the engine. 

1. I tested the compression and it is right around 125 PSI on both cylinders
2. I opened the exhaust and did a visual verification. Nothing suspicious there. Since its a new engine
3. I installed a Primer kit (Top carb) and I prime 3 times before I do a cold start
4. All 4 spark plugs are working fine. I used spark plug tester and I also tested each spark manually (for sparks)
5. There are 2 coils and I am not sure If the order of electrodes matter. In each coil, I connected + on the top and - to the bottom electrode on each coil (I am still not sure about this).
6. I am going to install a choke in both the carbs (just got the parts)
7. I cleaned all the jets and I have idler 45, needle 2.78 and main jet 180. The clip position is in the middle
8. The Airscrew is 1 1/2 turns out
9. I am using Ethanol free fuel.

This is my sequence of starting. (Seattle gets cold in the nights)

1. Turn on master switch
2. Apply primer 3 times (3 strokes, first stroke usually gets little or no gas) to the top carb
3. Throttle fully closed (Also tried with slightly open as well)
4. Click starter button. After couple of tries there is a fire happening in the engine and the smoke comes out. The EGT rises from 50F - 110F . then cools down to 80F or so.
5. Clicking starter button after 10 seconds pause again. (I accidentally burned the starter once by over heating it)


I cannot get the engine started. Not sure where or what I am doing wrong.  Is my starting steps correct? What am I missing? Appreciate any tips from previous owners.


I have attached the audio of the engine during the startup. You can hear the engine fires for a second. (Unzip the file to get the audio)


RE: Trouble Starting MZ202 - Eblezien - 06-21-2018

I'm not familiar with the mz202 but had a 2 stroke that acted similar and after chasing possible issues found that my reed valves needed to be replaced (they weren't sealing).  Maybe take a look at that.


RE: Trouble Starting MZ202 - shakirhussain - 06-21-2018

(06-21-2018, 04:23 AM)Eblezien Wrote: I'm not familiar with the mz202 but had a 2 stroke that acted similar and after chasing possible issues found that my reed valves needed to be replaced (they weren't sealing).  Maybe take a look at that.


Thanks. will check that.


RE: Trouble Starting MZ202 - mosquito - 06-21-2018

Sounds like a fuel delivery issue. It starts and runs initially on the prime and then dies because the carbs are not delivering any fuel. Are the floats adjusted correctly? Is there fuel in the float bowl?
Did it run well when you went up to 5500 initially or is the highest you could get the rpm to? If its the latter then maybe the flywheel key has sheared and your timing is off.


RE: Trouble Starting MZ202 - shakirhussain - 06-21-2018

(06-21-2018, 03:16 PM)mosquito Wrote: Sounds like a fuel delivery issue.  It starts and runs initially on the prime and then dies because the carbs are not delivering any fuel.  Are the floats adjusted correctly?  Is there fuel in the float bowl?
Did it run well when you went up to 5500 initially or is the highest you could get the rpm to?  If its the latter then maybe the flywheel key has sheared and your timing is off.


Fuel fills the bowl. There was one defective float (Mechanic found it) and I replaced all 4 floats. . When I got to 5500 first time, the needles in the RPM were off (see picture). So didn't go beyond that. The engine was hot and I was able to start multiple times that day. Without issues. Then from next day, I couldn't. Mike also suggested fuel delivery as the first thing to look. Now I am convinced the fuel delivery is happening correctly (there is no blockage). 

I am suspecting the timing as well.


RE: Trouble Starting MZ202 - FlyGuy - 06-21-2018

I think you need to get Mike Messex up there!




RE: Trouble Starting MZ202 - Frederic Moreau - 06-24-2018

Hello,

I had the same issue at the begining... The only think i did to be able to start it with 100% success was to open more throttle but remember, as soon as it starts you have to get it back under a certain number of rpm for you to stay just out of main rotor engagement during the heating process. You have to stay under engagement or go directly after engagement, don't stay inbetween as you will quickly "kill" your cluntch ;-)

So yes, it is a fuel delivery issue happening only in cold engin conditions.


RE: Trouble Starting MZ202 - FlyGuy - 06-24-2018

It still points to fuel flow issues. Check vent tubing if not correct system will pull a vaccum and cut off fuel. Check fuel lines, fuel does not like to flow up hill. 

This is only my opinion but to someone that has worked on may of these 202 configurations the problem might be simple to fix and a lot quicker. Second and this is not to pick at you but you have no experience with a Mosquito. What is the history of the ship, how much were you told about its past history? When I finished building mine it was great to have someone that knew the craft inside-out perform the initial startup and hoover. I did not know what sound was normal and what was not. How much vibration is too much, not based on you opinion but based on running up and flying many of these craft.

I have had Mike at my place looking over my 285 and another set of eyes on my machine and knowing that things that I my not have looked at were looked at by someone who knows the machine. It let me concentrate on flying and not on wondering if the heli is OK.

Just my 2 cents.


RE: Trouble Starting MZ202 - shakirhussain - 06-25-2018

(06-24-2018, 10:30 AM)Frederic Moreau Wrote: Hello,

I had the same issue at the begining... The only think i did to be able to start it with 100% success was to open more throttle but remember, as soon as it starts you have to get it back under a certain number of rpm for you to stay just out of main rotor engagement during the heating process. You have to stay under engagement or go directly after engagement, don't stay inbetween as you will quickly "kill" your cluntch ;-)

So yes, it is a fuel delivery issue happening only in cold engin conditions.

Did you apply plunger or choke and went more on throttle?

(06-21-2018, 06:11 AM)shakirhussain Wrote:
(06-21-2018, 04:23 AM)Eblezien Wrote: I'm not familiar with the mz202 but had a 2 stroke that acted similar and after chasing possible issues found that my reed valves needed to be replaced (they weren't sealing).  Maybe take a look at that.


Thanks. will check that.

Read valves seems good undamaged. Its also new engine. So didn't expected it to be bad.


RE: Trouble Starting MZ202 - Frederic Moreau - 06-25-2018

(06-25-2018, 06:50 AM)shakirhussain Wrote:
(06-24-2018, 10:30 AM)Frederic Moreau Wrote: Hello,

I had the same issue at the begining... The only think i did to be able to start it with 100% success was to open more throttle but remember, as soon as it starts you have to get it back under a certain number of rpm for you to stay just out of main rotor engagement during the heating process. You have to stay under engagement or go directly after engagement, don't stay inbetween as you will quickly "kill" your cluntch ;-)

So yes, it is a fuel delivery issue happening only in cold engin conditions.

Did you apply plunger or choke and went more on throttle?
---> Yes, i applied no more than 3 push of priming pear, the choke and more gaz... when really needed



(06-21-2018, 06:11 AM)shakirhussain Wrote:
(06-21-2018, 04:23 AM)Eblezien Wrote: I'm not familiar with the mz202 but had a 2 stroke that acted similar and after chasing possible issues found that my reed valves needed to be replaced (they weren't sealing).  Maybe take a look at that.


Thanks. will check that.

Read valves seems good undamaged. Its also new engine. So didn't expected it to be bad.