Timing problems

I have a 1991 Campion with an

I have a 1991 Campion with an odd problem. It has a 4.3L mercruiser. I have just put a new engine in this boat and it runs good under no load. Under load it acts as if it needs more timing so I advanced it farther and runs awesome. Then I got it home and checked the timing and it was at 22 BTDC. So this is along way from the spec of 8. But when I put to 8 it seems to lack power at the top-end and RPM. So I thought maybe the ignition module wasn't advancing it far enough if at all. But in fact at 8 degrees it advances to 21 degrees at 2500RPM. Is that enough? I found it odd that at 22 BTDC timing that it started so well without your typical kick back that you would get with to much timing. This is a Thunderbolt IV system somebody please help it is driving me insane trying to figure this out. It ran fine before the engine swap what could have possibly changed?

"The way it works is the way y

"The way it works is the way you think it should.

Initial (8 ') plus the advance from the timing control module (22) and when fully advanced should give you 30'

I am not sure what the V6 module should be but I think you should be looking at 32-34 degrees total. Does the module say 22' advance on it?

I could be wrong, I will check one of my books when I go home from work.

With that said, If you are getting only a total of 21 with 8 initial that says the module is giving you 13 degrees of electronic advance.....NG
Does this engine have a knock sensor? ANYONE? I dont believe they were used in '91 but dont remember.

Are you sure the plug wires are in order?


Look at the ing sensor under the cap. Is it all caroded? If not and all looks good replace the timing control module.


Just so you know Almost every boat runs perfect under no load!!! LOL"