Yamaha 220 Excel (Microcomputer)??

[WetNKnotty]

Does anybody have any experience with these computers? My motor runs perfect when I bypass the microcomputer per the manual, however, when I plug it in it does not get any spark. I got another used computer and still nothing?! I know with electronics it is possible to have a couple bad units, but is there anything else that could cause this other than a HUGE expense of replacing computers? Thanks so much guys, Im new to the forum. I have a 1993 220 Angler and I am ready to get out on the water!!

[Kalhgar02]

Does anybody have any experience with these computers? My motor runs perfect when I bypass the microcomputer per the manual, however, when I plug it in it does not get any spark. I got another used computer and still nothing?! I know with electronics it is possible to have a couple bad car parts units, but is there anything else that could cause this other than a HUGE expense of replacing computers? Thanks so much guys, Im new to the forum. I have a 1993 220 Angler and I am ready to get out on the water!!

Not sure about these computers as I have never used them..

[boats.net]

Need to test ignition components first.

[WetNKnotty]

How do I test the components? Could that cause the cpu not to fire spark or extremely weak spark?

*Again, when I bypass the computer, it starts right up and runs.

*Update - I tested the yellow wire going to the computer and its getting around 10 volts while cranking

[WetNKnotty]

Update:

Last night I decided to trace down the sensors and started with the crank sensor. I followed the wires coming down off of the sensor and what do you know, I bend the wire at a crease and they break in two with the typical green corrosion embedded throughout. I cut out all the corrosion and connected new wire... started right up. Unbelievable. I was moments away from spending a decent amount of money on purchasing a new microcomputer. Whew. Dodged that bullet for now. Now the top carb is dumping fuel. Must be a stuck float. I just had them rebuit too, will make a call to them tomorrow. Thanks guys!

[99yam40]

trash getting into the needle and seat and not allowing them to seat properly has nothing to do with just having them gone through.
It can hide in the lines or pumps and then hit the carbs soon after putting everything back together if they are not cleaned/ flushed

[WetNKnotty]

@ 99YAM40-
I hear ya. I do think that has a lot to do with it also. Having two filters should help out with that though. The computer is not working again. It wont start or fire spark. At this point im thinking maybe wiring or another sensor?

Ps) it starts and runs perfectly when I bypass the computer

[99yam40]

pick up a Yamaha service manual for you motor and read up on testing the ignition system.
Worth every penny to have a guide with steps, equipment needed, and the specs for the motor you are working on.

Some motors will drop spark if voltage gets too low at ECU while cranking over. Something to read up about.

But you need to be testing everything you can instead of guessing

[WetNKnotty]

Yeah, that's probably the best bet. I tested the yellow wire at the computer again and now its only getting 5-6 volts w/ the ign on. I jumped the wire and still couldnt get it to fire. While the ign was on, I smelled something burning a bit and noticed the oil tank was bubbling and trickling out the bottom onto the harness on the side of the motor?? I have a mechanic coming to check it out tomorrow. I wish I could figure it out myself, and im especially stumped being that I had it running perfect two days ago... Oh well. Typical electronics I guess...