Can a bad rectifier cause F115 to idle terribe?

[rocket350]

My rectifier went bad so I found a cheap aftermarket replacement for just $30 so I thought I's try it. I plugged it in and it started and idled normal for about 5 seconds. Then it started misfiring and revving up and down. I unplugged it and everything was fine (not charging of course) so I called the company and they sent a new one out to me. I installed it and seemed to fix the issue - ran great on muffs with a solid charge.

I dropped the boat into the water for the 1st time since fall, started her up and started doing the same thing. Erratic idle and misfiring. If I touched the throttle it would stall.

I removed the cowl and unplugged the rectifier. She started right up and ran great. We did some fishing and maybe put 5 miles on the boat before heading back.

I am going to order the way-more expensive Yamaha brand rectifier. I am assuming the previous two Chinese aftermarket rectifiers are junk.

So my question(s) - can a rectifier effect the idle and performance? It obviously does because when I unplug it everything is fine. Could there be something else causing this erratic idol with the rectifier plugged in?

BTW- there are no diagnostic coded being produced.

[rodbolt17]

its over heating the ECU.
but it may or may not be the charging system.

[rocket350]

Whhaaaaaat! This is driving me crazy. With both cheap Chinese rectifiers it produces charging voltage but does the weird idle. With the old bad rectifier it runs fine but doesn't charge. It was replaced last year supposedly from the shop but it looks like they put a used one in but I could be wrong. With it unplugged it runs fine, just no charge.

What can I check? The only thing behind the rectifier that I'm aware of is the pulser coil.

Okay so here is the story... the boat would stall when you trimmed the motor. I know - weak batteries usually and bought the boat like that. It never went away but was worse when you 1st started it. Then later into the season rpms were lacking under WOT so I took it in. The shop said they cleaned the injectors for the rpm issue and replaced the rectifier for the trim issue. The 1st time I took it out it ran great, beached the boat, then after swimming, took off. While getting it on plane, the boat chugged once or twice then stalled and would not start. After about 15 min, it started and ran great since but seemed to have charging issues since. So I'm thinking that is when the rectifier went out. And possibly the ecu overheated causing my starting issue that day?

Sorry for the long post. I'm trying paint a clear picture.

[99yam40]

pulser coils do not go to the rectifier, lighting coil feed it.

Have you tried monitoring the peak voltages like the service manual calls out to test charging system?

[rodbolt17]

you do realize it takes about 9 amps at 12V just to run the pumps,ECU, sensors and injectors???

[bajakeith]

grounds

I've seen this issue before and many times was a bad ground.....

[rocket350]

I took it to the shop. They said 3-4 days. Its day 10 now. I called 2 days ago and the mechanic said I might have a bad ISC valve, but its not related to my charging issue and that he needs to call Yamaha.

I called this afternoon and after being on hold she said the mechanic was with a customer and he'd call me back. They never called me back. I'm so frustrated.... seas are 1-2' on Saturday here in NC. Bonito and Spanish should be running. Ugh. If I ever get a diagnosis then I'll update in case anyone experiences this.

By the way I checked and cleaned grounds and also voltage stayed at a solid 13.something volts even while increasing rpms.

[bajakeith]

Hi Rocket

BTW I was talking about a bad ground on the main wireing to the motor about using the trim and the motor dieing,, not your idle issue!!