2002 F40 CDI Unit Replacement, HELP!!!

[matskot]

Hey all, I am hoping you can help. I have a 2002 F40 4 Stroke that I have had issues with it dying out on acceleration. brought it to my guy and he cleaned the carbs and changed all my fluids and filters and I am still having trouble. After further testing he told me that the CDI unit is toast but wants to charge me an arm and a leg for the part and to put it in. It couldn't be easier to get at so I am planning to do it myself. I am just wondering if it should be just a plug in and go kind of thing or if there would be any adjustments that would have to be made to anything after it is changed. Any info would be greatly appreciated as I am oviously new to this stuff!

Thanks in Advance, Matt

[99yam40]

Not sure about the 4 strokes, but on my 2 stroke there is a timing adjustment.
It would be a good idea to pick up a Yamaha service manual for your motor, it will give you all the steps needed along with the specs

What did he say is wrong with the CDI? Is it not advancing the timing?

The manual will give ways to test things before replacing to make sure what the problem is.

[matskot]

I believe that must be what it is , not advancing the timing. I remember him telling me something about the temperature at idle was say 20? for example and at a certain rpm it should be higher and it isn't and thats when it dies? maybe the temp is the way you check if the timing is advancing, as I said I am new to this stuff.... The problem I have is that the motor runs fine in neutral and you can rev it up with the warm up lever and all is well but under load is when I have problems. He told me they tried another CDI that they had at the shop that worked but wouldn't shut off and it ran fine......

[99yam40]

A timing light is what is used to check the timing.
Not sure of what the temp thing is you are speaking of.
On my C40, as the motor warms up a temp switch tells the CDI it is warm and then the CDI drops the timing down to the idle spec.
Sounds like you definitely need to get a manual and read up on testing the different systems.

A bad CDI would cause a loss of spark or a timing issue in my opinion.
Yours kind of sounds like a fuel issue, but I am not familiar with the 4 strokes

[matskot]

Agreed I definitely have to read up on this, I know nothing about motors but am sick of spending money on repairs. from what i was told it is definitley not a fuel issue. My mechanic said he spent half a day, which he didn't charge me for, doing every other test to make sure it was nothing else, and that it was surely the cdi. This is where I am at..... Looking for a good service manual....

[99yam40]

Yamaha 2002 Outboard Service Repair manual download
here is a web site that some have said was good ,but I have never used it.
Some like the Yamaha manual and others the after market ones

In my opinion it is easier to test the compression/ leak down of the cylinders and the ignition system and if nothing is found wrong with that then chase the fuel issue which is not something you can say for sure what is wrong with testing except the fuel supply pressure and vacuum