Yamaha 9.9 4-stroke high speed misfire

[seasport 22]

My 92' Yamaha 4-stroke cuts out whenever pushed to a fast troll (smooth to about 2 knots only-pushes my boat 4.5-5 knots when running properly).<br />Problem definitly appears electrical. New plugs and carb kit had no effect. Resistance checks per service manual o.k. except the "lighting coil" which reads ~.05 ohms and should be .34 to .52. Also the oil pressure light is dim and pulses, getting worse at higher rpm's. I changed the oil and cleaned the filter. Oil pressure switch appears to be o.k. Could a problem in this oil pressure lighting circuit be restricting power in an attempt to protect engine? Do I replace the entire stator assembly to fix the "lighting coil" ?

 

[marinegrh]

Re: Yamaha 9.9 4-stroke high speed misfire

by looking at a 92 f9.9, your specs arent in the yamaha tune up spec pulser coil resistance for a 92-93should be around 210ohms + - 20% charge coil 350 ohms, cdi output loaded 85 volts<br />195 at 1500, ign coil secondary resistance 4.1kohms + - 15%, but this info is if from the yama tune up book, good luck

 

[seasport 22]

Re: Yamaha 9.9 4-stroke high speed misfire

thanks for the input, marinegrh. reading 205 on pulser, 350 on charge and 4.25k on ignition secondary. just discovered no continuity on one plug cap and 5k on the other. i think 5k is correct so i have one of these on order.