Can I add a shim to reduce compression?

[kevinmach1]

My fustration is that my new Nirto sport runs hot and the kills. It wont restart very easily until it cools down. It seems to make very little difference if the body is on or off and I have cut up my brand new body as much as I going to. I am not running to lean, and I have upgraded to a pro trx blue head. I also run 10% nitro.
It seems to have gobs of power and compression so I wonder if adding an additioanal shim under the head (I have 3 now) would hurt anything physically. I cant see anything wrong with trying it.
This is my first nitro car, and it wont be my last.....
Thanks, Kevin

[TMAXX MASHER]

shouldn't be a problem, i would have thought going a bit richer on the high and low speed needles would have worked better. i can run 40% in my trx pro 15 with the right needle settings, but i actually seem to make the best hp with 20% top fuel. oh, a funny thing is i dont have any shims on my head at all. there should have been some but there wheren't.

later

[kevinmach1]

You would think I need to go richer, but I have tryed running on the rich side so that fuel is dripping out the exhaust and It smokes like a freight train. still gets hot.

[Super D]

Is the body drilled out for air flow?

[kevinmach1]

yes, lots of holes for airflow. does not mke any difference even running with the top off

[Super D]

Is the body drilled out for air flow?

[TMAXX MASHER]

i found the most likely problem, you have a single needle carb right? most likely the factory setting for the low speed needle is to lean but you cannot adjust it since its a single needle carb.

if you swapped to a dual needle carb like the trx pro uses then you can adjust low & high speed needles. speaking from experience if the low speed needle is set incorrectly my motor will not even start, if to lean it will run hot right from the start until it dies just like you said.

later

[Subaru]

Kevin: your truck maybe overgeared, try using a smaller clutch bell or a larger spur gear.

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My Nitro Sport gets squirly at wot

[Rodbr]

What do you call hot? My engine runs at about 270. I thought this was hot but I found out the engine can run as high as 300. Look at Traxxas website

http://www.traxxas.com/support/howto/trx_trouble_carburatorpro.htm

If you read this page you will see that Traxxas says the engine is tuned for 300 to 325

[Yude_Lose_2_my_Sport]

Wow! I checked that web site about the 300+ degree thingy...does anyone else run thiers that hot? I try to keep my pro 15 at about 220 degrees (with the help of an on board mip digital temp gage).

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Send it.

[Nitrochoid]

Another obscure item to check could be the fuel lines. After much of the same problems, I replaced both of the fuel lines and the problem magically went away. I talked with Traxxas about it and they figured there must have been a pinhole leak in the line to the carb, even though I couldn't detect it after removing the line. It is a long shot, but a cheap maintenance item. Good luck.

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trochoid-adj. Rotation around an axis

[Contra MAXX]

Mine actually runs very well right in the 290 range, and I'm just finishing its first gallon with no noticeable problems.