Help Please! No spark on two cylinders.

[gibdog205]

First of all thank you for any help or input you may provide. I have a 1990 nitro with a evinrude 150xp. When i bought it, it had a new cdi on it and i was having a dead short problem hooking up the battery and traced that to a bad rectifier. Replaced the rectifier and that fixed the dead short. First time i took it out on the water it ran really rough at low speeds, loading up and had no power out of the hole. I started checking things and found it is only running on four cylinders. The middle left and the upper right cylinders are not firing. The coils were all cracked and original so i put six new coils and wires on it . Still do not have spark to these two cylinders. The cdi has been replaced im afraid that its the stator. I tested the timer base and it has 1.5-1.8 ohms on all leads from white to blue,green, and purple. The stator has 895 ohms from brown/brown&yellow and 95.6 ohms from orange/orange&black. Im not sure how to check dva voltages does it need to be running or what? Are these readings low enough to be the problem? Please Help im @ my wits end trying to get this thing right for my trip next week. Thanks to all!

 

[emdsapmgr]

Re: Help Please! No spark on two cylinders.

Your ohm readings for the timer base seem unusual. The factory service manual lists 360 ohms on a Stevens meter, or 970 ohms on a Merc-o-tronic meter. The factory service manual also provides voltage test procedures for each component. Personally, I prefer these measurments instead of the ohm tests. When you turn the engine over, you should have minimum 200 volts output from the stator as registered on a "peak-reading" voltmeter. That same meter should read voltage output of .2 volts or higher on the timer base. To check the power pack, you connect that same peak reading voltmeter to each of the 6 primary coil leads from the pack. When cranking, the meter should register 175 volts or higher on each lead. Are you working from a factory service manual?

 

[gibdog205]

Re: Help Please! No spark on two cylinders.

emdsamgr,
Thank you for your input. I am not working from a factory service manual. I was working from a link i found on here from boatparts.com that gave me those measurments. Is there a downloadable service manual so i can get it asap or do i have to order a hard copy. Anyways im using a fluke multimeter for my readings and it sounds like i need a different meter and service manual. The other source told me 1000 ohms from brown-brown/yellow on the stator and i had 895. Also 100 ohms from orange-orange/black and i have 95.6. i understand you dont care for ohm readings but what do think of these results? Timerbase readings were exactly what the other source said it should be 1-2 ohms from white to blue,green, or purple. I will search for a manual and different meter while i wait to hear form you. Thanks again greatly.

 

[emdsapmgr]

Re: Help Please! No spark on two cylinders.

You should be able to buy a simple peak reading attachement which will plug into any normal voltmeter and provide the readings you need. Get an original hard copy service manual from the original publisher: Ken Cook Co., in Milwaukee. They are also on the web.
The 1990 factory manual says: the 35 amp stator should ohm 850 volts plus or minus 85 between the a and b and the c and d plug terminals. (you may have to make a jumper...) To test the timer base, the voltmeter red lead should be attached to terminal d in the port connector and the black should be tested between the a, then b, then c. You will get 360 ohms plus or minus 30 on a Stevens AT-101 meter and 970 ohms plus or minus 100 on a MercOTrionic M700 meter. Repeat this procedure on the starboard connector. Attach the red lead to the port timer base terminal D and the black lead to the starboard terminal d: should be 230 ohms plus or minus 30. As you can see, the manual shows different readings depending on which meter is used. That's why I personally prefer the volt readings.