QuestionQUESTION: Howard, Jon here with the 76 Midget (1275 in it). I have been, for 2 weeks banging my head over a no-start. I have changed cap,wires,points--re gaps plugs, points. Tested compression-ok; used test lamp off pos and neg coil lead with ignition on to test primary ignition-ok; tested same and cranked motor by hand, test light blinks properly as the points open/close. I tested coil with tapping - lead to ground unit to check for spark off coil lead-ok; tested ohm off coil-ok. Spark-ok. I then turned to fuel--re-set carbs down 12 flats. When I crank; i have no combustion. It just cranks over and over till I kill the battery. If I full choke and try--within a few I wet the plugs. I pulled the carbs down, nothing sticking. I then dropped the fuel and re-filled--no luck. What's next?
JGP
ANSWER: Hi Jon,
You have been testing a lot but I didn't see where you tested the end result on each.
Pull #1 plug and lay it on a metal part of the engine and put your thumb over the plug hole and have someone spin the engine. Each time the the piston comes up on compression it will blow your thumb off of the plug hole with a "Pop" and watch the spark at the plug to see that they both happen at the same time. If it is "Pop"-"Click" or "Click-"Pop" the timing may be too far out to run.
As far as it being a fuel problem all you need to do is spray a little starter fluid into the intake when trying to start to see if tries to start and then you will know if it is a fuel problem.
One more test, run a manifold pressure test to see how much cranking vacuum you have. (throttles closed)
Let me know,
Howard
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QUESTION: I did what you asked--minus the started fluid (i'll try that tommorrow), but
here is what I found. VAC I measured off the vacuum advance hose--the
needle bounced at each crank to 15 on the scale.(It is measure on gauge as,
in HG). I did the spark test--the pop is exact at the time of the spark. Here
though is what we noticed--the spark was faint, faint, faint, bright.
Sometimes almost not there. I started looking at the coil--took all the leads
off it and measured just below 1 ohm. I have a resistor that the negative
leads go into that says 6 ohms on it. Not sure if this helps, but I am
courious if the coil is weak given the poor spark.
Feel like a expense paid trip to Canada?
Frustrately yours,
Jon-G
ANSWER: Jon, the spark must be thick and colored blue (not in bright sun light) so if you see a thread size yellow or orange color, the spark is weak and can be the cause so run the spray test and if still no start you need to look to the ignition as a fault.
What ignition system do you have?
Howard
---------- FOLLOW-UP ----------
QUESTION: Howard, John with the 76 midget (1275 put in it) I may have really buggered
this up. I am looking at coil. I have one lead coming from bottom of
distributer (25D) to neg side of coil. I have two other wires (replaced at
some point so can't determine source, both are now white) both coming
from wire loom--one goes to positive side of coil, other to negative. I have a
Lucas Sport Coil, model DLB105 (non-ballast).
I had at one point, lead coming from the loom to a white brick, then to the
coil--I was told to remove that with this new coil.
There is a good chance the wires are wired to wrong sides of coil.
JGP
AnswerJon, If you have a pointed distributor now, you should have just one wire from the dist to the negative side of the coil (white w/black tracer). The power resistor can be discarded along with two plain white wires. You need the two white w/light green tracer wires connected to the positive side of the coil. There is a second white w/black tracer wire that goes to the tach and that should be connected with the other white w/black tracer wire from the points to the negative side of the coil.
The white w/blue tracer wire that originally went to the dist from the power resistor can be discarded.
Howard
