2000 XR6 ignition system. Timing issues

[4Bassin]

Hi, I have a 2000 XR6 that suddenly lost power. It has problems getting out of its own way. I suspect the spark advance module as I was able to improve the performance by adding 3 degrees to the max timing. This was a temporary adjustment to see if there was any improvement. The mechanical timing was set correctly at 20degrees at wot and the boat would barely get on plane with 2 people on board. It would not get on plane with water in the live wells. I have already done all the basic stuff including checking fuel filters, changing spark plugs, and verifying the carbs are functioning ok. All carbs are feeding fuel at the same rate as seen visually during wide open throttle with the front air box off.
I suspect the module but I can't find any good documentation that explains its operation. Does anyone know how much the spark advance module should advance timing? What is the total advance? This motor has the new style cdi modules and the spark advance module seems to be incorporated with the idle control module. Short of replacing the module is there any test I can do to confirm it's operation?
FWIW it idles fine and starts easily. I was tempted to advance the timing more than I did but was concerned about detonation.

 

[CharlieB]

Re: 2000 XR6 ignition system. Timing issues

Many owners have disconnected the Idle/Advance Module and dropped it over the side (accidentally, of course!).

Set max timing at 23 and adjust idle speed with idle timing as necessary.

Spark test all just to be sure that you haven't lost spark anywhere.

 

[j_martin]

Re: 2000 XR6 ignition system. Timing issues

If you suspect the advance module, disconnect it and try running without it and stock timing. The difference would be a few hundred RPM at WOT, maybe. You don't need the module either for advance, or for idle stabilization if the engine is in basically good condition. If you permanently remove it, you can change your WOT timing to 23 degrees.

The theory of operation is in the Genuine mercury maintenance manual. Basically it goes like this.

idle stabilization:
if idle speed falls below a set point, timing is advanced prox 3 degrees.

Advance:
at 5000 rpm, timing is advanced prox 4 degrees (23 total)
at 5500 rpm, timing is retarded 6 degrees (17 degrees total)

It gives you a slightly retarded timing (19 degees) at mid range, full advance, half throttle. A little timing kick at 5000 rpm, and a warranty protection wall at 5500 rpm. On a bass boat, none of these are needed.

Don't advance the timing for a test. If you over advance it, especially with today's crap gas, you could easily make a ventilated crown piston on the fly.

BTW, your symptoms point more toward a stator or switchbox problem. Factory manual and DVA will pinpoint it in about ten minutes in the driveway.

hope it helps
john

 

[4Bassin]

Re: 2000 XR6 ignition system. Timing issues

Thanks for the replies, I finally found a manual and will check the stator. I didn't think to disconnect the spark advance module and try it. Appreciate the help....

 

[jmj120]

Re: 2000 XR6 ignition system. Timing issues

I'd be willing to bet you've lost spark. I lost spark on 2-4-6 and had about the same symptoms.

 

[4Bassin]

Re: 2000 XR6 ignition system. Timing issues

Nope, all cylinders are firing. That was checked as part of the initial diagnostics.

 

[jmj120]

Re: 2000 XR6 ignition system. Timing issues

Nope, all cylinders are firing. That was checked as part of the initial diagnostics.

Did you check it with a spark gap tester? Just asking, I had the same problem. It would jump the plug gap a little, but when connected to a gap tester, nothing. Weak spark...

 

[4Bassin]

Re: 2000 XR6 ignition system. Timing issues

We pretty well confirmed the module to be bad. I bumped the timing to 24 degrees and we ran the boat with the livewell full and two people in it. It got up on plane and ran fairly decent. After that we disconnected the module and ran the same test again. There was no difference in the performance. It looks like the module is bad and we are confident enough now to spend the $300 for a new one. Thanks for the help guys, it was appreciated.

 

[j_martin]

Re: 2000 XR6 ignition system. Timing issues

We pretty well confirmed the module to be bad. I bumped the timing to 24 degrees and we ran the boat with the livewell full and two people in it. It got up on plane and ran fairly decent. After that we disconnected the module and ran the same test again. There was no difference in the performance. It looks like the module is bad and we are confident enough now to spend the $300 for a new one. Thanks for the help guys, it was appreciated.

Why?

 

[CharlieB]

Re: 2000 XR6 ignition system. Timing issues

I may be guessing, but I have found that some customers, even when told by much more experienced techs, some still believe that they must follow the OEM Service Manual to the letter.

Blind Faith, maybe?