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problem engine MZ202
(10-05-2020, 06:05 PM)mauri Wrote:
(10-04-2020, 03:44 PM)jimwitkowski Wrote: Mauri, per what Leo said, here is a video of my engine with a case leak found. It caused it to run hot due to the added air causing it to run lean.
what product are you using to check for the leak? also it seems that you used a compressed air system to turn the engine, do you have any photos?
Mauri, I no longer own my Mosquito helicopter. I'm sorry I don't have any pictures of how I did the test. I will try to explain how I did it to you, its been about 5 years so I will do the best I can. I removed the exhaust from the engine block and made aluminum flat plates that went between the block and exhaust manifold. The reason is to seal closed so when the air pressure is applied it doesn't leak out. I did the same thing with the carbs. I made plates that mounted between the carbs and block. The plates can be made from flat plastic or aluminum, they just need to be flat to seal the block. If I remember correctly I think I hooked the compressor air hose to a fitting on the engine block that is a vacunm for the fuel pump to operate. The compressor I used was just a small one that is used to fill bicycle tires, I think I had the pressure set at about 20 pounds. I then mixed some dish washing soap with water in a spray bottle and sprayed it along the seam on the block.If there is a leak you should see it just like in my video I posted.
No more than 6lbs or you can will blow the crank shafts seals, ( a design limit)-- air leaks will manifest the entire rpm range more so at higher rpm and won't be intermittent. It leaks or doesnt. They will show in the temperatures differences as air leak will lean the affected cylinder and run hot They will also show on a carb balance attempt as pressures won't match at full throttle.
When it drops power does the motor still run smoothly or does it get rough?
When it drops power does the EGT go up or down?
Have you looked at the spark plug colour?
You need to isolate whether this is fuel or ignition. Plug colour and temps will help with this.
Have a look through the exhaust ports to see the condition of the piston and the bores, if it's getting hot and nipping up it will loose power before it seizes. So, how long have you run it once you loose power? anything over a minute means it's not an imminent seizure.
As already mentioned replace the fuel filters and also inspect the pickups in the tank for possible debris. Also check that your fuel tank vent is not blocked!
Lastly you may have failing CDI units and/or a voltage regulator fault. It's best to have a voltmeter in the dash to show charge voltage, the CDIs will shut down on both under AND over voltage!
Once you have collected all the info get back to either myself or Mike and we can assist you further.
Best regards
-Mosquito sales and services Down Under-
Mauri, did you discover what was causing your engine problem? If you did please explain what the cause was. I'm sure many owners would be interested in knowing. Thanks
Compression test: 135 PSI on both cylinders. it's acceptable?

Crankcase Leak Test: Pressurized up to 6 PSI. there is a 1 PSI drop in pressure every 5 minutes. it's acceptable?
Mauri, see Jim's suggestion when doing crankcase leak test is to spray soapy water along all seams and look for air bubbling out.
(10-24-2020, 06:41 PM)grevis Wrote: Mauri, see Jim's suggestion when doing crankcase leak test is to spray soapy water along all seams and look for air bubbling out.
I agree with you  ....
yes that's acceptable,

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