Still having problems

sharpshooter

Recruit
Joined
Apr 9, 2006
Messages
4
I have a 2000 40hp 4 stroke Yamaha. I was not getting fire on the #2 cyl. I just replaced the ECM unit last Fri. and took it out to run. It ran rough at first then after about 10 min. of running it felt like you hit a NOS button and took off better than it ever run. I'm guessing it was some bad fuel in the line that cleared it's self out. Well Sunday morning I head out to fish at daylight and it starts and runs like a champ. On up in the day the wind got up and made the water rough. As I head out of a cove and get in the rough water the motor starts to act like it did before I replaced the ECM. Loses some power and runs rough. I took it to about 1/4 throttle and rode the waves out to some calm water. When it got calm I opened it up all the way and it ran good, but about half way across the calm water it started getting rough again. I get home and pull the plugs and #2 is not firing again. #1 and #3 have fire. I pull the coil wire off of #3 and put it on #2 and get fire, same thing with the #1 wire on #2, so I know the coil is good. I talked to a Yamaha mech. and told him everything and he said "Yamaha electronics very rarely cause problems" that he would start with the fuel. It's hard to start on the fuel knowing the the #2 cyl. has no fire. Where do I go from here? I'm thinking it is the pulser coil or stator. Anybody ever had a problem like this?<br /><br />One more thing, if it is a faulty stator or pulser coil could it do any damage to my ECM?
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Still having problems

the stator charge coil powers all 3 ign coils, if one dies due to a stator they all die, rules out a stator, check the pulser coil resistance and the spark plug cap resistance, pulser wire colors are R/W to B and the caps unscrew from the plug wire,resistance should be 5kohms or so, do you have access to a peak reading voltmeter ?
 

KennyBradley

Seaman Apprentice
Joined
Jul 28, 2005
Messages
32
Re: Still having problems

Sharpshooter,<br /><br />Did you ever get your problem solved? I am having exactly the same problem with my 2001 30hp Yamaha four stroke.<br /><br />Kenny
 
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