Help Diagnosing engine issue

[cubaniche]

Basically what dabomb said. My speeds were gps proven too so I just gave up on diagnosing, what I now believe to have been, a tach issue. Granted, I did find a bunch if other things to fix while I was diagnosing this issue.
I replaced stator, the pulsers, etc. No change. I have a brand new CDI (just the computer, not the whole box) that I never installed. It was $$$.

But, if you don't want to remove the whole box and all wires, you can just remove the actual CDI from the box and disconnect all the wires to it, and swap. One thing to make sure of is that you connect the coils to the correct wires from the CDI so it sparks in the order its supposed to. The wires are labeled 1, 2, 3 and color coded.

 

[jjtherocketman]

No spark can be caused by several things. You've checked the easier stuff...kill switch, ignition switch, cleanout switches...Now to get into the stator electronics.

The stator has several functions. Charging the battery, providing the juice to the CDI for spark, and providing the signal (pulse) to the CDI to know WHEN to spark. So you need to find a manual online and grab a multimeter to start testing the lighting coil, charging coil, and pulser coils. If those all pass then I would start looking at testing out via swapping CDI between engines. They are a pain to remove but basically disconnect all wires, grounds, ect that are associated with the CDI and it pulls out. Sometimes a extra ground strap needs removed to get clearance.

Well, you weren't kidding about it being a pain. Still haven't started disconnecting all the wiring. Was hoping I could at least slide it out and get it where I could see it first, but no such luck there. It's wedged in pretty good behind a slew of wiring penetrations through the side walls. At least it appears that way. My original plan was just swap the boxes between engines and see if that solved it. Now I have a used CDI box that I believe is good that I'll try inserting first once I disconnect the current box and see if it starts. Before that, I'll check the coils. I already have the manual on my laptop downloaded, so have the table with peak voltages and resistance measurements to take. Just waiting for some time to dig into it. Why couldn't it just be one of them really easily changed out kill switches? LOL

 

[jjtherocketman]

Basically what dabomb said. My speeds were gps proven too so I just gave up on diagnosing, what I now believe to have been, a tach issue. Granted, I did find a bunch if other things to fix while I was diagnosing this issue.
I replaced stator, the pulsers, etc. No change. I have a brand new CDI (just the computer, not the whole box) that I never installed. It was $$$.

But, if you don't want to remove the whole box and all wires, you can just remove the actual CDI from the box and disconnect all the wires to it, and swap. One thing to make sure of is that you connect the coils to the correct wires from the CDI so it sparks in the order its supposed to. The wires are labeled 1, 2, 3 and color coded.

Yep, I saw the numbering on the wires. But it's not quite as easy as you make it sound to just "remove the CDI and disconnect it...." From what I can see (which you can't really see squat with it installed on the back bulkhead), it appears that you have to disconnect everything first just to get access to the CDI and then it seems like it's wedged in behind some ignition box penetrations. As if it won't come out unless you slide it in one direction....haven't figure out what that direction is just yet! But I'm learning more with each foray into this area and did buy a used CDI box on ebay (yes, risky and I HOPE it's good....looks good and clean). Going to check all the coils before taking that box out. This has definitely turned into more than I bargained for in trying to figure out why that engine is dead. A second pair of eyes and hands would help! And perhaps someone with real experience guiding me haha. Thanks for the help.

 

[dabomb6608]

Well, you weren't kidding about it being a pain. Still haven't started disconnecting all the wiring. Was hoping I could at least slide it out and get it where I could see it first, but no such luck there. It's wedged in pretty good behind a slew of wiring penetrations through the side walls. At least it appears that way. My original plan was just swap the boxes between engines and see if that solved it. Now I have a used CDI box that I believe is good that I'll try inserting first once I disconnect the current box and see if it starts. Before that, I'll check the coils. I already have the manual on my laptop downloaded, so have the table with peak voltages and resistance measurements to take. Just waiting for some time to dig into it. Why couldn't it just be one of them really easily changed out kill switches? LOL

Those wires coming into the side of the box are just held in by rubber grommets. They pull away from the box with a little wiggling. That will help with getting wires moved around, but you WILL need to unplug stuff to remove. No way around that unfortunately lol. Also very important. Disconnect the battery positive or negative cables. Very easy to short something and blow the CDI or other electronics.