How do you test the CDI box?

[Selby Brown]

I am having an intermittent problem with my C85 Yamaha outboard ignition system and I think it could be in the CDI box or one of the wires going to it. It will suddenly drop to 2000 rpm's and will stay there even with throttle wide open. I can switch it off and start it back up and it will run great until it does it again. Sometimes it will be hours or days before it does it again. It is driving me crazy. Ignition coils are new and carbs are super clean. Warning buzzer is not going off and sensor is good.

 

[rodbolt]

Re: How do you test the CDI box?

you can put a box on it for 350 dollars or so.<br /> or you can use the test wheel and check out the fuel system and CDI inputs and outputs when its failed.<br /> could be a pulser,could be the CDI or it could still be a fuel issue or a wire connection.<br /> does your C85 have the CDI with a movable timer in it or does it have a movable trigger assy under the flywheel ?

 

[Selby Brown]

Re: How do you test the CDI box?

The reason I think it is electical is when it dropped to 2000 rpm's the other day i just bumped the tilt switch and it took off like a bat out of hell and ran fine the rest of the day. It is hard to troubleshoot because it doesn't do it long enough to really test it. When you switch it off and remove the cover to test it the blasted thing runs fine when you start it back up. I can't make it do it unless it is in the water and under a load.

 

[rodbolt]

Re: How do you test the CDI box?

but ya still did not answer my question.<br /> ya gotta do that or no one can help ya.<br />as we cant see it and sometimes the manuals get fuzzy we ask questions to aid us in identifying exactly which of the 40 or so ign types yours has.

 

[Selby Brown]

Re: How do you test the CDI box?

Sorry about that Rodbolt. The model is a C85TLRS. Does that help?

 

[Dragonddice]

Re: How do you test the CDI box?

If you bumped the trim and it started working it sounds to me like you may have a wire grounding out, check the harness for rubbed spots and pinched points Im not an expert but check for the little simple stuff first I always say.

 

[rodbolt]

Re: How do you test the CDI box?

not really, i dont keep many manuals here at home, thats why i was asking about the physical layout of the cdi.<br />that and the manuals are noted for misprints.

 

[Selby Brown]

Re: How do you test the CDI box?

I will look at it when I get off work and get back with you