Reason for sudden drop in mpg?

[snyper316]

Ok i found the gap specs which i will post the page and the box i got tonight has got 0 then 10 20 then a big space then it says 30 and 40 i set the gap at 15 in between 10 and 20 and got the spark to jump the gap on mine also one problem tho dont know what this would be but when i turned the key of and grabbed the clip to change wires i got a little bit of a shock..Spark gap test.pdf

[yamagrl]

I was looking for the actual spec for the 1st gen's but could not find it, I believe that spec may be for the 2nd gen. It does not matter, the point is you should get a spark at least twice the distance of the stock gap. Try at 0.100 and if it doesn't work try 0.080. The point being all the sparks should be around the same, if you have one wire that is much weaker than the others there is an issue with either the wire, the coil itself, or with the plug cap assembly.

 

Question on your new wires. Did you buy new assemblies, or did you buy separate wires and separate caps? Also, speaking of caps, on the coil side of the wire did you install the o rings on the plug wires under the screw on caps for the coil? These are important, they keep the plug wire from vibrating loose. Also, it is a good practice to snip 1/8" to 1/4" of the wire off each time you take the plug wire off. The reason for this is the metal prong spreads the center conductor apart, and when you reinstall without cutting the end off it may not make as good contact resulting in a weaker spark. Of course then the o ring has to be pushed further down the wire, the screw on cap will push the o ring back towards the end when you screw it on. Also, you should inspect the coil secondary connection as crud and corrosion can, and will get in there! There should be no green stuff in there!!

 

On the spark plug boot, there is an assembly in there that unscrews and has a spring, a disc, and a resistor element. They get dirty and cause problems as well. Somewhere on this site is a thread about how to service these...

 

The spec is on page on page 7-16 of the 83-85 manual. It gives the procedure for using the Yam Electro tester. The spec is .24 minimum gap. I'm guessing that he procedure would be the same using a spark gap tester from your favorite auto parts store

 

YG

 

 

[bongobobny]

OK must have missed it with a quick look! The 0.1 may be a 2nd gen spec, had a carb vent issue a few years shutting down 2 cylinders and part of my troubleshooting was testing for good spark thinking maybe I had a coil or TCI issue...

[Bounder]

I have read both 5k and 10k ohm for spark plug cap resistance. The new ones I have were said to be 5k. Which is right?

[videoarizona]

5k.