timing problems

[delgao]

I have a 2000 5.0 merc that I rebuilded myself. I test the boat and everything was working fine but the timing of the ignition went off.s I did recheck the position of the piston (compr ) , the ignition pointing to the #1 plug wire and the the damper on the mark of timing chain cover. I turn the engine on and I turn the timing ligth and is off no matter how far you move the ignition .Also the engine is backfiring by the carb . PLEASE CAN ANYBODY GIVE ME A WORD.

 

[Don S]

Re: timing problems

I am going to do some assuming here, and assume you have a carbed engine with the Thunderbolt V ignition system. Since you didn't mention it, I would also bet you didn't put it in base timing mode to set the timing.
Here is the procedure from the service manual.

 

[delgao]

Re: timing problems

THANKS FOR THE ADVICE ! you just arised one issue here. When I did repaired the engine I used the ignition of the previous engine that was a 1995 thunderbolt IV with the thunderbolt IV module (IT is rigth to use or I must use a thunderbolt V ). And yes it is carburated . Like Isaid when I first run the boat IT WAS IN THE PROPER TIMING and runnig fine . I did not did that procedure the manual of the thunderbolt IV does not said so. So MY CONCERN NOW IS IF I MUST USE THUNDERBOLT V IGNITION . AND THANKS AGAIN .

 

[Don S]

Re: timing problems

There is nothing wrong with using the Thunderbolt IV ignition, and it doesn't require being put into base timing mode.
Have you checked the distributor cap for cracks, moisture, or carbon tracking inside? What shape are the plug wires in?

 

[GLENN M]

Re: timing problems

I have a 2000 5.0 merc that I rebuilded myself. I test the boat and everything was working fine but the timing of the ignition went off.s I did recheck the position of the piston (compr ) , the ignition pointing to the #1 plug wire and the the damper on the mark of timing chain cover. I turn the engine on and I turn the timing ligth and is off no matter how far you move the ignition .Also the engine is backfiring by the carb . PLEASE CAN ANYBODY GIVE ME A WORD.

Well what I can say almost for sure.once engine is running and distributor tightened they don't usually move. Being a 2000 it must be electronic so unfortunately my best advice would be for you to get a manuel and start at the top go through till you solve .reply only way unless you want a bunch of people guessing,those symptomscould describe 20 I'll ness's read info top of page someone spent some tme for just moments like these