ORIGINAL: Destruktiveone
Just as the title says i recently bought a K5.9 motor from a LHS and i did my best at breaking it in right. My problem is that the motor STAYS around 250 degrees.. no matter how much richer i run it, I cant get it to drop down more than around 5 degrees. I thought since the motor only cost $200 i figured it would be ok to just let it run that hot and try not to run it for long periods of time. Needless to say, Today during a normal run (Jumps, a few straight stretches, and some grass dougnuts) the glow plug literally shot out of the top like it was a gun. It only went about 2 feet above the motor but it still blew out! When it landed i tried to pick it up and it was suuuper hot so i took my thermometer and stuck it against the plug and it read over 280 before i took the thermo off. That must have meant that inside the motor was about the same temp. I have no idea what im doing wrong but i cant tune the motor because of how hot it is. I HAVE to keep it running waaay rich just to keep the temp at 250. If anybody knows of anything im doing wrong then please let me know. lol Cuz i cant figure it out for anything and im about to contact HPI and get a new motor thinkin this one is faulty. Thanks for any help!
I know alot of people like to tune their motors based on temperature, but I have personally never used a temperature gun and have always been able to get a very good tune on my cars. I'm not saying that using a temperature gun is wrong, I just don't see a reason to use one with such significant operating temperature differences from one engine to the next. If you graphedthe ideal operating temperature of all the engines out there, the distribution would be huge. Again, not dissing anybody who likes temperature guns,I just don't see the need for them. Tune it so it runs smooth and cleans out on the high end leaving a light stream of smoke, like a small smoke trail as you drive it by.
As for your other issues, keep your glow plug tight and check it every now and then. The fact it popped out doesn't mean much of anything, just that it wasn't tight enough to begin with. Someone mentioned sealing the engine and that is good advice. I would seal at the carbuerator and engine backplate, the plate behind the pullstart if you have one.Tuning an engine with air leaks is a nightmare. Not saying yours has any, but better safe than sorry.