[Taluzer45]

Hi, I have a problem with my 2003 legend 550f. It seems to be running on 1 cylinder. It sounds like a bravo and has a top speed of about 60-70. I have had the sled looks at previously (before this problem came about) and the motor looks quite good, the pistons and cylinders are in MINT condition and the compression is decent (110) which is somewhat on the low side but it ran mint also. Its running SPX (?) race pistons and the carbs were checked, synced, and set up... and was a complete rebuild by a certified mechanic 2 years ago. i was just wondering what could be the cause of this issue...


Thanks,
Scott

 

[mmgg]

start simple change the plugs.

 

[Taluzer45]

The plugs are brand new and so are the back up plugs, both sets are gapped to spec.

Thanks for the input,
Scott

 

[Taluzer45]

My uncle suggested that the oil injection is too high and it's fouling the plugs and preventing a spark, I lost the oil injection last year and needed a new cable, so we replaced it and adjusted it... ( p.s. the sled smokes even when warm ) ,can this be the cause of my problems?, considering the dealer around here said it's $ 500 for the coil, im wishing it's not that!

 

[mmgg]

It could be alot of things,,

plug boots/wires
If the smoke is blue it could be the oil injection adjustment.
if black than over rich fuel.
Try a hotter plug if you are fouling plugs
most fan engines smoke a bit and run rich when the temp. is above -10 c
one of your chokes may be stuck on.
also if you use cheap oil it will smoke alot more than a premuim oil.
check the fan belt to make sure it isn't wornout.
if it still runs rich when it is -10c than you may have to rejet or adj. the carbs

60-70 mph for a fan is not terrible,it could be clutching, jammed or broken clutch spring, a worn belt , worn suspension part or the track too tight

First confirm it is running one one cyd. touch the plug to see if it is cold, or use a spark detector to see when it misfires.

 

[Taluzer45]

When I said 60-70 I ment kph and im thinking it may of been the choke because my friend said it used to do it to him ocassionally so im going to try the sled tomorrow and see what happens... and usually I can get 130 ish (kph) out of the sled..

 

[hoxdesigns]

I have a 340 and each cylinder's plug is gold colored. The problem is both cylinders won't run the same time because the CDI/ ignition coil is firing both plugs the same time at ONCE per revolution. If both plugs are hooked up, the default is the forward one will fire and the rear one won't. Top RPM is the same, 4,700 RPM, if the rear plug is hooked up or not. If I run the rear cylinder, max RPM is 3,900. My engine should go to 6,500+ RPM. Why is the ignition coil only firing ONCE per revolution? I took video of the plugs external to the engine, slowed the video to count sparks per revolution. The plug that's not firing, of course, is covered with fuel/oil. So I'm only burning half the fuel and have about one third power, as only one plug is firing, the crank is having to take the other piston for a ride. I have even taken the longer plug wire (PTO cylinder) and hooked it to the opposite cylinder...no change. If I remove the either spark plug physically, max RPM is 2,500.