Spitfire electrical problems???

[liquitisplit80]

Finally got around to working on the spitty this weekend to check a problem and some strange things are happening. First, it will start right up and idle fine but it sounds like its missing on one cylinder. This was confirmed by me touching the exhaust, mag side hot clutch side cold. Absolutely no power when I squeeze the throttle, even wide open. Doesnt bog. Doesnt want to die. Just a smooth one cylinder idle. Getting good spark on both cyl. Good compression. Swapped plugs- same thing. All of the lights worked at first, high/low, tail and brake. So I shut it off getting frustrated and after lunch went back and started it up (one pull) and, you guessed it, it runs like a champ!! However, now my low beam headlight doesnt work! What gives!!! It did this a couple of years ago (missing on one cyl. Shut it off then went back to it 5 min. later and ran great the rest of the day.) Only then I didnt lose my headlight.
Anybody else have this problem????

[JDT]

Chances are the two issues are not related.

I would be checking your H/L switch and or bulb and also try a known good working CDI box swap to see if you fire on two.

Unless your problem is compression related on the cold cylinder. Maybe a ring that is sticking and frees itself.

A compression check cold and warm may shed some light on this.

[liquitisplit80]

So what your thinking is it could be a weak CDI causing the intermittent running on one cylinder? Who still makes a CDI for them??

[JDT]

Matt may have the aftermarket CDI's on New Breed Parts.

Otherwise they should be available from the usual suppliers.

The CDI's in Spits are about as reliable as the Prestolites.
And that is not good.

[liquitisplit80]

Guess I'll be hunting down a CDI. Would'nt be a bad idea to have a spare anyway. Thanks.

[kreechur]

I don't believe i remember seeing the CDI boxes in the new breed parts or not, but i bought one for my 79 spitty here: http://www.psep.biz/store/john_deere_sn ... _boxes.htm

It didn't look exactly like the original, but it mounts the same, and plugs are the same.

It runs great since i put it in although due the the overly crappy winter, it has not been tested out in the field. only on a jackstand in the garage... When mine went, the ohm tests were ok but you need the John Deere tester to properly test, as an ohm won't test it under load. Mine did have what appeared to be spark on both sides, and both sides were firing, but motor ran really weak. After new CDI it ran extremely good on the jack stand.

I agree with what's been said, i believe you have two different issues. Ohm out the switch and wiring to check for broken wire or high resistance. Also make sure it's a good bulb. check voltages at the plug for high and low, and make sure your not getting more than 12v AC. If your getting higher voltages beyond idle, could be a voltage regulator is bad or has a bad ground. Chasing electrical problems can be a pain in the back side, but can be very rewarding when found and fixed.

[liquitisplit80]

Thanks kreechur, I'll check 'em out!

[weandsta1d]

still reading about your problem but cannot come up with a big solution. i just searched but still no direct answer. still concentrating on fused and cleaning. best is to have a auto electrician.




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