electrical problem

[CRANKIE]

yamaha 90 trla stalls when you put in gear,unplug the computer from the crank sensor and it does not stall. does this mean the cdi,crank sensor or ??<br />thanks in advance

 

[Ray Neudecker]

Re: electrical problem

Normally, this would be a carb problem. Still trying to figure out how it ran at all with the crank sensor unplugged.

 

[CRANKIE]

Re: electrical problem

on the side of the "box" it says to unplug conector "a" if runs bad or stalls, so i did and it did not stall then it says to take to a yamaha dealer. conector "a" is the sensor at the flywheel.

 

[CRANKIE]

Re: electrical problem

Ok more on this yamaha,with a spark tester on #1 plug wire i start the engine after a few secs it stalls. when it stalls the spark stops first.<br />if i unplug the crank sensor and run it,it will not stall.<br />if i unplug the two yellow wires from the cdi box that are looped together and plug back in the crank sensor it will not stall.<br />what are the yellow wires from the cdi box for?<br />the manual does not say they just show them looped together. any info would help.

 

[rodbolt]

Re: electrical problem

the spark on one cyl is synthezized. its made by the computer and timing is also computer controlled. the yellow wire locks the timing and spark if disconnected. time to buy a service manual and start testing. start with a basic spark and compression and move on from there. you will need a few test harness's, a cd-77 meter or equivalent, an ohmmeter and patience. the really is no "good" test for the CDI. test all else then replace the cdi. but the CDI's just rarely fail.<br /> good luck and keep posting

 

[CRANKIE]

Re: electrical problem

Thanks for reply rodbolt, i have new cdi,manual,dva meter ect. all res tests are good on pluser coil,crank sensor and ign coil. output test on charge coil are funny. with yellow wire unpluged (bypass) i have no change from crank to running i think this is normal because of (bypass). if i plug back in the yellow wire i can not run it to test past 1500 rpm.if it runs in bypass charge coil/ign coil should be ok? two parts left crank sensor and pulser coil.<br />what do you think?

 

[CRANKIE]

Re: electrical problem

update! it was the stator even with good readings<br />and the right test equipment you can have a bad part