richardtf

just finished installing my new 3.3 carb, i didn't put sealant coz the guy from traxxas support told me its not needed the o ring would be fine, but Ive noticed that the idle is erratic,what are the sign of an air leak?


thanks

silverman1

That is one of the possible signs of an air leak. I read in my rc car action nitro engine tuning and repair guide that if you spray water with a spray bottle around the areas you could have leaks.

The manifold where the carb bolts down to the intake

The crankcase where it bolts up which is behind your starter

The fuel tube inlet where it bolts to the carb via the high speed mixture screw.

Sray water around each seperate area one at time, If your engine shuts of instantly that is where your air leak is the water spray would teporarily seal the leak causing a rich condition.

Do them in steps because if spray all suspect areas at the same time it will be hard to pin point your culprit.

Sealing an engine is no big deal and it really does help performance, and while you have your engine torn down you can check your sleeve and piston fit. There are articles on the subject in this forum.

Don't forget to check your fuel tank and fuel lines as well. Make sure your tank is empty, and rub soapy water around the seams & lid blow into the fuel line with your mouth, if you have leaks you see bubbles forming.

for the the fuel lines hold your finger over one end and blow in, you should hear no air leaks from the lines.

Air leaks can wreak havoc on engine performance.

Good luck.

dgz69er

excellent reply

SLAYERDUDE

^+1^

You can also do the soapy water thing on the engine.
Block off carb and header (w/o muffler) open the HSN a few turns, open carb gap so LSN isn't closed and blow in fuel line.
Look for bubbles.


SLAYER