In addition to the new Forza 1/10 Buggy with the vx18 engine I also have the HyperSpeed single speed with the vx16 motor.

On the vx16 motor, it starts fine with the electric starter and runs fine until it is warmed up. Once it is warmed up, it runs ok as long as the revs are kept up. If you come to a stop and try to let it idle, it will idle for a little bit and then stall. Important details are:

1) Was broken in using the slower speeds method (going from 0 to 1/4 throttle, back down, 0 to 1/2 throttle, back down) for 5 tanks of fuel
2) Doesn't seem to matter if idle adjustment is set higher or lower, still does the same thing
3) low speed adjustment is set flush with the surrounding ring, but I have tried leaner and richer with same result
4) high speed is set 2.75 turns from the closed position
5) using Traxxas Nitro 20% fuel - have gone through about 1/2 to 3/4 gallons now on this engine
6) seems to happen once engine warms up, does not seem to do it when cold
7) engine runs about 250 degrees with outside temp in the 40's
8) once it stalls it is not very easy to fire it up again - have to crank several times and play with gas to fire up

Any thoughts?

sounds like a blown engine, when it stalls and you cant start it, check the compression by turning the flywheel, if the compression is low, its blown.

Oh, oh.... You might be right. I just tried turning the flywheel with the engine cold and although there is some resistance, it is light and then goes to TDC where it has the two "clicks" before coming back down to BDC. I just compared it to my new vx18 engine that has never been run yet and that has a lot more resistance than the vx16 has now. Should this broken in vx16 motor have just about the same resistance on the flywheel that the new vx18 has that has never been run yet?

not as much as a new engine but there should be a decent amount of compression, its best to check when the engine is giving you a hard time starting, i guarantee that you will have little to no compression when engine is warm. its good though because if i understand, exceed will replace your engine free of charge, the customer just has to pay for shipping, check out this post by the exceed guy: http://www.rcuniverse.com/forum/m_7035131/tm.htm

post #16

Thanks for the help. I will swap out the engine tonight (I carry an extra just for cases like this) and see what happens after break in period. If the engine is blown, I PM the Exceed rep and see what assistance they can provide since the engine has less than one gallon of nitro through it.

BTW, congrats on the 10,000 post mark.

thanks bro, take it easy during the break in, make sure your running rich

I had the same problem with my VX16 engine. Had almost 1 gallon of fuel put in it before it locked up. And yes, it was broken in correctly and not run too lean. Just shipped it back to NitroRCX yesterday for replacement.