Just replaced several parts including shutters, cap, rotor, plugs, ignition pickup module in the distributor, coil wire etc.
The boat runs great, smooth, starts easy perfect temps, oil pressure etc. I noticed I am still about 2-3 mph slower than I was a year or so ago. I thought the tune might bring that back - but didnt. * It clearly needed the pickup, the old one was corroded and partially gone - and now my tach is nice and smooth, bounced all over prior.
Thought I would check the timing, and get back to basics - set everything exactly like the book says. When I lowered the idle down to the 700-800 range (it was at almost 1100), I noticed the engine would run stable for a bit, then surge up a couple hundred rpm, then eventually back down after a few seconds. I threw a timing light on it. At ~700 ish, it's right at 8 degrees, when it surges up, looks like it going toward about 14 (of course this is est since the metal thingy stops at 12.) Does the advance kick in that quickly with the thunderbolt, or do I have some other problem?)
Not sure what to think. Coil, ign module, vacuum leak ... other?
Any diagnosis help would be appreciated.
Also - Not familiar with these thunderbolt ignitions - someone suggested to me that I dump it and get a dui, but I've read an awful lot of comments about how the stock t-bolt 4 is a great ign. opinions? (Note engine is all stock except for a edelbrock performer intake.)
The boat runs great, smooth, starts easy perfect temps, oil pressure etc. I noticed I am still about 2-3 mph slower than I was a year or so ago. I thought the tune might bring that back - but didnt. * It clearly needed the pickup, the old one was corroded and partially gone - and now my tach is nice and smooth, bounced all over prior.
Thought I would check the timing, and get back to basics - set everything exactly like the book says. When I lowered the idle down to the 700-800 range (it was at almost 1100), I noticed the engine would run stable for a bit, then surge up a couple hundred rpm, then eventually back down after a few seconds. I threw a timing light on it. At ~700 ish, it's right at 8 degrees, when it surges up, looks like it going toward about 14 (of course this is est since the metal thingy stops at 12.) Does the advance kick in that quickly with the thunderbolt, or do I have some other problem?)
Not sure what to think. Coil, ign module, vacuum leak ... other?
Any diagnosis help would be appreciated.
Also - Not familiar with these thunderbolt ignitions - someone suggested to me that I dump it and get a dui, but I've read an awful lot of comments about how the stock t-bolt 4 is a great ign. opinions? (Note engine is all stock except for a edelbrock performer intake.)
