ORIGINAL: DarZeelon
ORIGINAL: le fou
...I have a manual. Did you run the engine at half throttle per manufacturer's instruction? I thought that DarZeelon recommended not to do that.
Le Fou,
Running the engine at half-throttle achieves nothing in a tapered-bore engine, because the engine will be very slow to reach its normal operating temperature.
It will probably do no damage, though...
But at the same time, I do not see what the manufacturer thinks can be achieved, in recommending that the customer does that...
Can you scan and post that page in the manual, or the whole thing?
It's all right here...
http://www.rcuniverse.com/forum/m_1890371/tm.htm
There is some good and bad information out there about break in proceedures for ABC type engines...... some info is a mixture of both. In general, a proceedure outline by an engine manufacturer should be followed as written.
Other engine manufacturers have their noted proceedures. The proceedures depend a lot on materials. Jett uses special alloy aluminum for all pistons, and all sleeves are TRUE chrome plated. For a Jett, that first minute of being rich does no damage to the piston or sleeve. It is no different than starting a Jett or any other ABC engine when cold and at idle. The proceedure outlined in the instructions and on the web site is very tried and true. Always follow it with a Jett engine, and the engine will run flawlessly.
Something of note. 'Taper bore' engines and AAC/ABC engines can be different. Some have a 'fixed' taper that does not change or changes unevenly. A well designed AAC/ABC engine has a taper and piston/sleeve fit that DOES change. Both the piston and sleeve change with temperature. When the engine is cold (at start) there is an interference that you can feel and hear turning over the engine... with a Jett, the audible 'squeek' is a good thing to hear! As soon as the engine starts (for sport engines, at idle) the engine begins to warm up, creating the appropriate fit between piston and sleeve. As you take the engine to full power and it reaches operating temperature, the fit becomes optimal, and you will hear the engine rpm increase to its full potential. If anything, you want it on the 'tight' side.
Isn't this where it all started? "The new and improved upgraded break-in thread"... ?