Can you test a CDI?

Posts: 8

Buggy was running great at the buggy bash, then near the end I was having trouble restarting it. It acted like the battery was dying. I was running with the lights on most of the last day and thought I had just drained the battery.

Came home, put the battery on the charger with same result. Engine tries to turn over but no go. It really sounds like it is struggling to start.

So I got a new battery, all charged up (triple checked charge) - same response.

Tried to start the buggy by crossing over the ignition coil - same response.

I've read several threads and it seems a faulty CDI is a common cause with symptoms like this. Can you test a CDI?

Posts: 1684

I've seen bad petcocks cause this problem.
1st thing to do is check the oil.
If there is a bunch of gas in the oil, then
there may be too much gas in the cylinder
causing high compression and making it too
hard for the starter to turn the engine over.
Next remove the spark plug and try to turn
the engine over a few times with the starter.
WATCH OUT though.....I've had some shoot
gas everywhere (like 4-5 ft) out the plug
hole. Could be a fire hazard too.
If it turns over real good without the plug in,
then it may be possible that you have a weak
starter.

Posts: 8

Took spark plug out (saw and smelled gas on plug) - put new one it - tried to start - same response. Best way to describe it, the buggy sounds tired. Its like its trying to start but just cant crank over. I can post a video of the buggy trying to start if that would help.

Double-checked voltage on battery, solid 12.55 V.

Tried without the spark plug in, saw good spark on the plug and engine sounded a little better in terms of trying to start but not much.

Posts: 1221

have you checked the ground wire from battery to engine and hot wire from battery to solenoid to make sure they are good and tight with no corrosion on the ends or glazed.
i have seen vehicles that have done this to make you think it is a lazy starter.then all it be was the a little corrosion on wire ends not letting it get its full power to turn motor over.
might not be your problem, just thought i would mention that though
pud

Posts: 8

ricduncan & Pud - thanks for the suggestions - checked battery connections at engine and at solenoid - all good.

Check voltage on solenoid terminals when starting 12 v. Would checking the voltage coming out of the solenoid when starting do any good?

Also checked voltage on starter when trying to crank, only 8 volts, is that normal?

Any place else I can check voltage to narrow this down?

Keep the suggestions coming, much appreciated!

Posts: 195

Ok, so I took the starter off and disassembled it. It looked ok, not that I'm an expert on starters. Still may order a new one.

Anyone have any tips for putting a starter back together again? The springs in the bottom portion are a bit of a challenge to get back in.