I bet we would be surprised how hot the carbs get in some installations. I know of (3) examples of engines that I helped with that had problems and adding just a bit of cool air to the carb area resolved the issues completely.

I think we could learn a bit from full scale engines that use carburetors. They are tightly cowled / baffled for cooling but the carbs are out the bottom and receive only fresh air, just like our model twins. Some fuel injected engines run the fuel plumbing on top of the engine where it can get very hot ..... at is does sometimes cause idle and starting problems when hot.

Originally Posted by mshabandar

i like your answer , it have a logic which never thought about it .

if this is the case do you think a canister or tuned pipe will solve the issue as they will take the heat far away from the carb?


but one more thing , the issue appear even when i start the engine for the first time on the field , i mean the first start each time i go to the flying field when the engine still cold

I wonder if you tuned the engines when the carbs were hot, chasing the settings a bit and they are still a bit lean on the low end. Just a thought .... nothing is ever 100% sure on our engines.

Originally Posted by Truckracer

I wonder if you tuned the engines when the carbs were hot, chasing the settings a bit and they are still a bit lean on the low end. Just a thought .... nothing is ever 100% sure on our engines.

i tuned it many many times , hot , cold


but you know what ?, your post remined me about something, on the Aeroworks - Extra i added some fins to make better air flow and till now the issue didnt came back after the third replaced carborator, while on the Aerotech Velox , the cowl is completely closed except for the area near the cylinder and Muffler and that maight cased the issue after the seconed replaced carb.

as of now i am on Casablanca for business and will go back to dubai tomorrow and will first do cleaning for the carb then do some openings in the cowl and update you about the result

Tune it with the cowl off and see if you still have the problem when you fly with the cowl off. Then you will know if its a cooling problem.

Originally Posted by jaync

Tune it with the cowl off and see if you still have the problem when you fly with the cowl off. Then you will know if its a cooling problem.

thats good idea also

Originally Posted by jaync

Tune it with the cowl off and see if you still have the problem when you fly with the cowl off. Then you will know if its a cooling problem.

+1

Originally Posted by Truckracer

+1

+ 1

Originally Posted by mshabandar

i have an issue with my DLE 55RA , i have three dle 55ra engines all of them have the same issue , they use to run very good with 22x8 prop, they produce 7200RPM on full throttle

after 10 flights the issue will start appear, on high speed there is no issue but on idle the engine will be 1500 rpm which is normal , then after almost 10 second on idle , the rpm will increase to 3000 then engin die , this mean fuel is not reaching to the engine. for the first time i notice this issue , i replaced the full carb including reads . the engine will return normal then after 10 flights the issue will start again ,

i tried to remove the inline filter between the enging and the tank , then i removed the T between the engine and the tank and make direct fuel line to the engine but all my tries not solved the issue , it is only solved when i replace the carb completely.

now i have 3 engines and 6 extra carbs cleaned them and kept as standby , but i got fed up, and need permanent solution for this issue

finally , it worth to mention that i am using Redline sentetic oil for two stroke engines , my mix is the standard mix 1cc oil for every 30 cc fuel ( 33 cc oil per 1 liter of fuel) , the fuel i am using is 88 octane


please advise if you faced this issue and have proper solution for it .

thanks 

3 engines 6 carbs, and when you replace a carb or clean it the engine will run fine for about 10 flights. You have a fuel contamination problem

Originally Posted by stingray528i

3 engines 6 carbs, and when you replace a carb or clean it the engine will run fine for about 10 flights. You have a fuel contamination problem

I would agree with that but it seems the problem is only on the bottom end though. You would think that a fuel problem would affect the carb across the whole RPM range. It would certainly be worth while to try a different fuel source.

I have a DLE 55 RA.
It is important to cool the rear of the cylinder and isolate the carburetor.

Wow, that's one solution! Looks bullet proof!

Yes, now i have a canister

What thoughts, comments, or input does anyone have on running only the flex header on the DLE 55RA to help address overheating in a warbird like the Top Flite 86" Spitfire?

http://www.dlenginesaustralia.com/dl...ex-header.html

Originally Posted by Truckracer

I would agree with that but it seems the problem is only on the bottom end though. You would think that a fuel problem would affect the carb across the whole RPM range. It would certainly be worth while to try a different fuel source.

hi again ,

well i remove the cowl and run the engine and the same problem remain , so the heat is not the issue of my problem .

one of experts in our flying field notice the problem and he tried his best to fix it and he was so angry because he didnt solve the issue

then he asked me what is the mix ratio , i answered 1 to 30 , he said this is the recommended mis for mineral oil not for synthetic oil . he run the engine with petrol only ( no oil ) to clean the carb then we made a mix of 1 to 45 ( redline synthetic oil ) then the problem get solved .

What spark plug are you using? Is it the factory plug?