KE25 revs to full throttle after starting (newb needs help)

[Bce777]

I purchased my first nitro about a week ago, but 2 days ago every time I try to start it revs to full throttle. I tried setting my carb to factory settings of HSN 3.5 turns out from close, LSN flush and idle gap of 0.5mm to no avail. Throttle trim is set to 0. What else can I check?

 

[override]

Turn your transmitter and receiver on and check all your end and trims points, is your carb slide pulled out any when you aren't applying throttle? If so, adjust your trims or linkages and verify your idle gap is correct. If your carb slide is all the way in and proper idle gap set then it sounds like you may have an air leak causing a lean run away?

Anyway you can post up a video?

 

[Bce777]

Turn your transmitter and receiver on and check all your end and trims points, is your carb slide pulled out any when you aren't applying throttle? If so, adjust your trims or linkages and verify your idle gap is correct. If your carb slide is all the way in and proper idle gap set then it sounds like you may have an air leak causing a lean run away?

Anyway you can post up a video?

Trims and linkages look good, What’s the best way to check for air leaks and to fix them?

 

[override]

You will need to plug the exhaust and carb intake, hook a fuel line up and with the throttle open blow air into it to hold pressure onto the engine (shouldn't take much), take some soapy water and a brush and wipe all the areas of the engine around carb, back plate and head and look for bubbles. That's the gist of it anyways.

Being that this is a new car I don't think that would be your problem but if that motor isn't properly sealed it very well could be the culprit. Rather than going through the hassle of checking for air leaks you would do yourself a service to go ahead and just seal up that motor.

Here is a short guide from a quick google search. I don't think the guide mentions it but some oring sealing grease works wonders on the needle threads/orings as well.

 

[Bce777]

Found out the carburetor pinch bolt is leaking I’ve applied RTV to both sides, but could this little bolt leaking actually be the cause of my engine screaming high revs at startup?

 

[cbaker65]

Found out the carburetor pinch bolt is leaking I’ve applied RTV to both sides, but could this little bolt leaking actually be the cause of my engine screaming high revs at startup?

Any air leak would cause an engine to have high revs ,it causes the engine to lean out ,also ,anything in between like a leaky
tank or dirty tank filter ,bad fuel pressure to the tank from the muffler or even a combination of it all!

The best thing to do ,is go an seal the engine ,make sure the head bolts are tight an while it sits an cures ,go over
the fuel system ,make sure the tank is clean & its filter ,make sure the tank lid seals good ,make sure all tubing is
good an in its right place ,also make sure that the header & pipe coupler is sealed tight with zip ties!.....

 

[Bce777]

Any air leak would cause an engine to have high revs ,it causes the engine to lean out ,also ,anything in between like a leaky
tank or dirty tank filter ,bad fuel pressure to the tank from the muffler or even a combination of it all!

The best thing to do ,is go an seal the engine ,make sure the head bolts are tight an while it sits an cures ,go over
the fuel system ,make sure the tank is clean & its filter ,make sure the tank lid seals good ,make sure all tubing is
good an in its right place ,also make sure that the header & pipe coupler is sealed tight with zip ties!.....

I started it today after letting the RTV dry, It’s not screaming at full speed at startup anymore thanks for the help guys. ?

 

[override]

I started it today after letting the RTV dry, It’s not screaming at full speed at startup anymore thanks for the help guys. ?

Glad you had success! Those air leaks can be a devil!