So my 454's should be maxing between 4400-4600 rpm I just got this boat less than a year ago and I checked the timing and the valve covers say 8°btdc? But I hear that that is more of a starting point? I believe idling around 8-900rpm it was 16° and I heard it should never go over 34°ish? And the motor stops advancing the timing on its own at 3500rpm so is this wrong? MY PRO LET is one motor is hitting 4400-4450 the other is hitting about 4000 rpm . The cap and wires look old...I have no idea about the fuel filter when it was last changed is that the best place to start general tune up things? I've tried adjusting the throttle on that motor and it seems to he opening all the way soooo what now guys and girls??

is total advance coming in at 30 to 32 degrees? replace cap and wires. stock thunderbolt 4 ign? check both ign boxes for what they are supposed to be. they say v6-14 or v8-22, something like that. that is engine and total advance that box adds. 88 pachanga. alpha or bravos? with both, but more likely with alphas, drives break and get replaced with ebay or craigslist drives. you could have 2 diff gear ratios. check props for same pitch. if alphas same rotation switch props. everything stays same, switch carbs. you may hafta pull drives and count turns between input-propshaft to verify gear ratio. you may also get more answers in the DIY or general engine questions forums above. this section is more for GPS and stereos and stuff.

I would do simple compression check first and go from there.

Gotcha yeah one of the drives has been replaced the other is original they appear to be 1.3? Both props are 21 pitch cleavers.

I'll try switching the props I guess sense I'm right next to the lake it will be easy to check. Yeah I think that total advance timing at the higher rpm is coming in at 30-32°

If there alpha's that is the problem 1.3 is no longer made.

Yeah they're alphas no the newer drive has 1.3 stamped in it. The older drive I can't seem to make out anymore