No Fire on cylinders 2,4,6

[mil0058]

Hello, long time reader but first time poster here. I have a 1988 Sea Ray Laguna 23 with dual Mercury 135 V6's with the same year engines. The motors are the white Sea Ray editions. After spending $1000 dollars in the spring to get them running "right", the engines ran flawlessly for about 20 hours. The port motor then fell off plane and would not reach 2000 rpms. The port engine had 2 switchboxes installed during the repair. After limping back to dock on one engine I started my troubleshooting. Thinking that since the ignition system was just worked on, I suspected fuel delivery. I changed the water seperators, inline fuel filter, and primer bulbs. I then attached the muffs to see what was going on. The engine would start up and idle very rough, but it was at this time that I saw the bottom carb leaking fuel out of the carb throat. It was leaking out of the bottom "tubes, vents"? I then got 3 carb gasket kits and cleaned the carbs according to the manual.

Again I hooked up the muffs and tried starting it. Although it seemed that I solved my leaking carburetor, the engine does not want to run. On occasion it would start up and rev to 2000-2500 rpms. I would immediatly shut it down afraid to blow the engine but it sounded like not all cylinders were firing. From here I went on to check the compression. All cylinders were well within specs 115-120 PSI. After conducting a spark test using an adjustable spark tester, I found that cylinders 2.4.6 were not firing. I tried swapping the 2 switchboxes to see if the problem would move with the switchboxes but it still would not fire on cylinders 2,4,6. I am not sure if that was proper procedure but I figured that it could not hurt. From here I am not really sure where to go, I am a pretty mechanically inclined person, but the ignition section of the manual confused me and I do not have a DVA meter. I was wondering if someone could give me some pointers and if I in fact do need to purchase a DVA. Can I do proper ignition testing if the motor will not start up?

Thanks in advance for your help.

 

[Coloradolakeboy]

Re: No Fire on cylinders 2,4,6

You may have to redo the Lync and Sync procedure. Also, with the plastic silencer cover off, hit the choke. See if the shutter valves on the sound attenuator are closing. You may have to spray some lubricant on the solenoid linkage if it is sticking. If they now close, hopefully that will get it started. You will need a DVA to run some of these tests. Look at pages 83-84 here. tests.
http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true

 

[jimmbo]

Re: No Fire on cylinders 2,4,6

Sound like you have a trigger problem or the wires from the trigger are shorting or open

 

[mil0058]

Re: No Fire on cylinders 2,4,6

Thanks for the responses, I will try the link and sync after work tomorrow. I think I saw a section in the manual on how to complete the link and sync. I'll post my results, or ask some more questions when I read the manual. Thanks again.

 

[sschefer]

Re: No Fire on cylinders 2,4,6

A link and synch won't fix a spark problem but if you rebuilt the carbs then you should do it anyway. It acctually sounds to me like a failed switchbox. Its not uncommon. Triggers share three coils in the following sequence 1,4 - 2,5 - 3,6. Loss of 2, 4, & 6 would mean a loss of 1, 3 and 5 also. Check the ground on the switch box and then disconnect the white bias wire between the two switch boxes and see if it comes back. If the ground fixes it then you're good to go, it removing the bias wire fixes it then you've got a bad switch box usually. You would want to get a DVA and trouble shoot further before you start throwing parts at it.

 

[Faztbullet]

Re: No Fire on cylinders 2,4,6

I agree that yopu should check your grounds. If you do disconnect the white/blk bia's wire and spark comes back the rear switch is bad not the one that is not firing.

 

[mil0058]

Re: No Fire on cylinders 2,4,6

Now that I think of it (as i am tossing and turnin in bed thinking about this dang engine) when I was Swapping switchboxes, I noticed that the mechanic partially cut the ground wire isulation heading to the inner switchbox as he was bolting on the outer box. Would this cause that switchbox to fry? Or would it be possible to cut new wire and reground that box again? The 2 switchboxes that he used were made by CDI. Looks like I have alot to look at tomorrow and more diagnostic tools to buy.

 

[mil0058]

Re: No Fire on cylinders 2,4,6

Update on what I have done so far. On Wednesday I checked my grounds and disconnected the bias wire between the two switchboxes. After doing this spark on cylinders 2,4,and 6 were still dead. I also checked the ground that was cut and it was only the insulation, not a clear cut. The DVA and timing light that I ordered should be in the mail today so I will begin the link and sync/DVA testing.

Coloradolakeboy, I am not sure what the sound attenuator is on the engine. Could you please elaborate what this is. I did a quick search and did not see it on my engine. Also, should I link and sync first and then do diagnostics with the DVA?

 

[Faztbullet]

Re: No Fire on cylinders 2,4,6

Disconnect the blk/yel off the switchboxes and pull the plugs to prevent starting. If spark comes back the internal harness has a problem. If it still does not spark swap the red and blue stator wire from firing pack to non firing, if it sparks now low speed side of stator has failed...

 

[CharlieB]

Re: No Fire on cylinders 2,4,6

You swapped switchboxes but the 'no spark' did NOT change.

Swap the stator leads between the switchboxes, I bet it changes now! You may have lost output on the low speed windings to one box.

DVA testing the stator is THE best method of confirming this, as there is NO RETURN on electrical parts.

 

[mil0058]

Re: No Fire on cylinders 2,4,6

Good afternoon all,

I conducted all of the tests that were listed above with no change. I still have no spark on the same cylinder bank. I did however discover that I made a mistake and its cylinders 1,3,5 that have no spark. Regaurdless the "no spark" never moved to the other bank. I got in the mail a peak voltage meter(DVA) but have no idea how to use it. I followed the CDI electronics trouble shoot guide and recieved a reading of 0 ohms between the ground and the blue wire and did not get any readings for the DVA test either. I did this for the running engine on my boat and got the same readings. I must be doing something wrong. Does anyone have advice or a thorough step by step guide to DVA testing a stator and powerpack?

Thanks again for your help, I did get the engine idling well after some simple carb adjustments though.

 

[mil0058]

Re: No Fire on cylinders 2,4,6

Just wanted to give an update on the issue that I had and hoping to help someone else out. After what seemed to be a long and tedious process of troubleshooting I determined that the Stator was malfunctioning. After pulling the flywheel, I noticed that part of the Stator was melted and I could see some wires showing through. Figuring that it was the culprit I installed a new one. Unfortunately this was not the only problem, although I assume a melted stator is no good.

I sent the 2 powerpacks into CDI Electronics to have tested (they were under the 2 year warranty). After about a week, I just called to check the status and the lady said that one tested good and one was faulty. The good one and a new warrenty one should arrive at my house tommorow free of charge. It is so nice to have a company stand by their product (especially electrical), I cant speak highly enough of them. We will see what happens when I install them, hopefully I can get out for Fall Striper here on the bay. Thanks everyone for the help.