Evolution 33cc help
08-31-2018 | 01:17 PM
#1
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Evolution 33cc help
I have a H9 Spitire with a 33cc Evolution engine. I have had two flights with two dead stick landings. Both times the engine quit when I tried to throttle back to 1/2. Both times i managed to land the aircraft without damage.
The engine was initially run on the ground using a 17 x 8 APC prop for approxately 1 hour using a 20 to 1 Redline gas oil mixture at a low throttle setting within issues in starting or getting a good transition from idle to full power. The engine would run through a full tank of fuel without any issues through all throttle settings. Other than a vibration issue the engine seemed to perform very well and I was impressed with it. The vibration issue was solved by changing the spinner nut (the original supplied nut was off centre) and balancing the spinner. All runs and flying was done without the cowling.
To fly the fuel mix was changed to a 30 to 1 mix and the engine retuned before flight and everything seemed to be good.
My question is has anyone had a similar issue with this engine and what was done to solve it? I seem to remember that there was a thread that talked about an air flow issue with front mounted carbs that would cause these engines to be unreliable. I have done searches and have not been able to find anything.
The engine was initially run on the ground using a 17 x 8 APC prop for approxately 1 hour using a 20 to 1 Redline gas oil mixture at a low throttle setting within issues in starting or getting a good transition from idle to full power. The engine would run through a full tank of fuel without any issues through all throttle settings. Other than a vibration issue the engine seemed to perform very well and I was impressed with it. The vibration issue was solved by changing the spinner nut (the original supplied nut was off centre) and balancing the spinner. All runs and flying was done without the cowling.
To fly the fuel mix was changed to a 30 to 1 mix and the engine retuned before flight and everything seemed to be good.
My question is has anyone had a similar issue with this engine and what was done to solve it? I seem to remember that there was a thread that talked about an air flow issue with front mounted carbs that would cause these engines to be unreliable. I have done searches and have not been able to find anything.
Last edited by youngguy; 08-31-2018 at 01:22 PM.
08-31-2018 | 01:23 PM
#2
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Yep.
The front mounted carb choke plate is your culprit, in the Spitfire it comes right in that intake, hits the choke plate and goes straight down, leaning out the engine and making it quit but it will run on the ground forever just fine.
The easy solution is to create an air dam, higher than the choke plate, mine is nothing more than aluminum foil thats held in place with a zip tie, its not pretty but it works like a champ.
The front mounted carb choke plate is your culprit, in the Spitfire it comes right in that intake, hits the choke plate and goes straight down, leaning out the engine and making it quit but it will run on the ground forever just fine.
The easy solution is to create an air dam, higher than the choke plate, mine is nothing more than aluminum foil thats held in place with a zip tie, its not pretty but it works like a champ.
09-01-2018 | 07:02 AM
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From: Edmonton,
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Yep.
The front mounted carb choke plate is your culprit, in the Spitfire it comes right in that intake, hits the choke plate and goes straight down, leaning out the engine and making it quit but it will run on the ground forever just fine.
The easy solution is to create an air dam, higher than the choke plate, mine is nothing more than aluminum foil thats held in place with a zip tie, its not pretty but it works like a champ.
The front mounted carb choke plate is your culprit, in the Spitfire it comes right in that intake, hits the choke plate and goes straight down, leaning out the engine and making it quit but it will run on the ground forever just fine.
The easy solution is to create an air dam, higher than the choke plate, mine is nothing more than aluminum foil thats held in place with a zip tie, its not pretty but it works like a champ.
