Logo
FULL SITE MENU

2002 Yamaha 115 TXRA Misfire/hardstart

K

kmaddox

New member
I have a 2002 Yamaha 115 TXRA 2 stroke that was sitting for several years and it appears to be randomly misfiring. The outboard will not start unless using starting fluid, and even then it is almost impossible to get started. It does not fire off like an engine that is having fuel problems would on starting fluid. Before anyone freaks out, the oiling system is working 100%, I have verified there is plenty of oil in the discharge ports, both tanks, and the engine smokes a lot when running (due to not all of the cylinders firing). There is plenty of oil to lubricate the engine and starting fluid was only used as a last resort and even then it only started once, but once it did it would stay running with random misfires on 1,2,3, and 4 checked with an inductive pickup on a timing light.

This is what I have done so far, and YES i thought it was a fuel problem at first, but I am 99.999% sure fuel is fine.

  1. Compression Test - All cylinders above 125 cold , some 130, no more than 5PSI difference.
  2. removed and cleaned carbs and all needles/seats. Everything looked amazing.
  3. Drained fuel tank completely, checked all fuel lines from the tank to the carbs.
  4. Cleaned fuel filter.
  5. Plugs are wet with fuel and oil when trying to start.
  6. Tested CDI output based on manual, it was NOT within spec on DC volts, but was in spec for AC volts. The manual says to test for DC volts but says to look for a "Peak" voltage which doesn't really make sense on DC volts.
  7. Tested charge coil, based on the manual's information this showed to be bad on the CDI's inputs, but the voltmeter does work and when it does run it does charge.
  8. Tested Pulser coil, based on what the manual is telling me this is bad.
  9. ALl test equipment was double checked for continuity and operations
  10. Cleaned all coil ground wires and various grounds on the engine, continuity between battery and engine grounds confirmed good.
  11. Coils all tested good.
Please help, I do not want to fire the parts canon and throw a charge coil and pulser coil at this unless those parts are known to cause this problem. The factory service manual is somewhat vague regarding the inputs to the CDI unit and what will happen if certain inputs do not work. Besides the problem appears to be intermittent or a component that has not completely failed but is on its way out.
 
Back
Top