Engine adjustments (high temp)

[RevoMan76]

I just finished breaking in my new OS .21TM on Traxxas 20% fuel. I stepped up and purchased a gallon of 30% Blue Thunder Sport fuel. I made some adjustments on my hsn settings (more rich) The motor was running at high temps during idle after switching to the higher % fuel. I richened the settings even more until it sputtered out (too rich) The temps were still high at idle. The only nitro engine I have ever messed with before was the TRX 3.3. Is it normal for this motor to run so hot at idle, or should I mess with another setting!:whhooo:

 

[HeartBreak]

You may have to add a head shim to run the 30%. I'm not entirely sure though. If you have the manual still, it will state whether or not you have to add it.

 

[brad55102]

what temps are you hitting, at idle,,, and at high speeds?

 

[Rolex]

If you overheat while just idling, you need to richen your LSN.

 

[RevoMan76]

If you overheat while just idling, you need to richen your LSN.

I will mess with that more tomorrow, the lsn. Thank you

You may have to add a head shim to run the 30%. I'm not entirely sure though. If you have the manual still, it will state whether or not you have to add it.

The manual does not say anything about different fuel % or adding head shims. Thanks for the info though!

 

[Rolex]

You will also need to reset the HSN for top speed since it's probably too rich right now.

 

[RevoMan76]

You will also need to reset the HSN for top speed since it's probably too rich right now.

I dont really know what u mean by that, still learning the whole high performance motor thing:\

 

[Scrogg]

I did a ton of research on the 21 TM when I bought mine. First off both those fuels are not good for the engine. Too much oil. Try something with 10-12% oil. Byron's Race or O'Donnell's, Sidewinder race blend, Trinity MHP. The nitro percentage does not matter, 20 or 30% will be fine. i ran 25% in mine.
I searched thru several forums and 99% of people who own this engine all said the same...they like to run hot. O.S. does not specify a temp in there manual, they say to run it where it performs and smokes.
Mine runs best between 250F-280F. 3 gallons and counting, not one fouled plug, no detonation marks, piston is clean, the compression is still great. Just keep it under 280 F in warm weather and under 250F in cooler weather. It will be fine. Do not add shims or remove shims. Be gentle with it for the first gallon and it will last a long time.

 

[RevoMan76]

I did a ton of research on the 21 TM when I bought mine. First off both those fuels are not good for the engine. Too much oil. Try something with 10-12% oil. Byron's Race or O'Donnell's, Sidewinder race blend, Trinity MHP. The nitro percentage does not matter, 20 or 30% will be fine. i ran 25% in mine.
I searched thru several forums and 99% of people who own this engine all said the same...they like to run hot. O.S. does not specify a temp in there manual, they say to run it where it performs and smokes.
Mine runs best between 250F-280F. 3 gallons and counting, not one fouled plug, no detonation marks, piston is clean, the compression is still great. Just keep it under 280 F in warm weather and under 250F in cooler weather. It will be fine. Do not add shims or remove shims. Be gentle with it for the first gallon and it will last a long time.

Thanx for the info. I have no choice with the fuels right now. Hobbytown and Hobby people in Las Vegas do not carry Byron's or O'Donnell's racing fuels. I just spent $40 on the Blue Thunder and still have 3/4 of a gal of the Traxxas 20% left. No money to spend on shipping more fuel to my house. Hobbytown won't even order either one of those fuels for me

 

[Scrogg]

Tell you hobbyshop to order you some real fuel.
If they carry the lower oil blends of the Blue Thunder that should work better for you.
I think Blue Thunder has a race blend and another called HP8. Just be careful with the 8% oil fuels. Very little room for error.

 

[RevoMan76]

Tell you hobbyshop to order you some real fuel.
If they carry the lower oil blends of the Blue Thunder that should work better for you.
I think Blue Thunder has a race blend and another called HP8. Just be careful with the 8% oil fuels. Very little room for error.

Am I going to hurt my engine by running the 30% Blue Thunder??:whhooo:

 

[Scrogg]

Not one bit. Just richen it up before you run the 30%.