how do the plugs look?  hows your fuel pressure at WOT?  i have a gauge on my fuel rail and i just sit back there while my gf floors the gogo pedal. 

ok if i were you i would look at what ive done, and then ask was it running right before i started? if the answer is no . well ... look the first thing as a mechanic your taught is to see if someone has been in there before if not then move on. it could be a lot of things. well good luck.

oh and who has the fastest reaction time to tell me what's wrong with this picture hahahah oh man

ok it looks a little lean, so lets start with the carb, well the throttle linkage make sure that when you press the gas pedal all the way down that the carb opens all the way. start with the easy stuff first!!!!! oh what size carb do you have and do you know what jets you have???

Is it just me or is that 45 a little short?

ding ding we have a winner haha, Hmm I'm not that big of a motor guy yet but aren't all the spark plugs supposed to be the same?

I don't think gap is the problem. Definately lean, lean, lean, although 1 plug looks kinda ok, and probably some timing issues. Yeah, get some decent MATCHING plugs......

I didn't quite get your first post. It's spinning to 3800 rpm max, and for how long before it seems to "lose power" and rpms drop? What impeller is in there, and what pump, for that matter. Could be important.

Personally, I wouldn't run anything under an 850 in any BB jet boat if I could help it. But at 3800 RPM on a 454, you certainly aren't running out of carb. And that is where I'd be looking. As said, secondaries not opening, severe jetting issues, as lean as you are, and the very low rpm, I'd be swapping carbs. But I have a few extra around here to do that with. At the very least, run it, then look down it's throat, not running, and open the thing up manually and see if the squirters are working on all four corners at least, but you're look at a carb overhaul at minimum. 

Ray   

I don't think gap is the problem. Definately lean, lean, lean, although 1 plug looks kinda ok, and probably some timing issues. Yeah, get some decent MATCHING plugs......

I didn't quite get your first post. It's spinning to 3800 rpm max, and for how long before it seems to "lose power" and rpms drop? What impeller is in there, and what pump, for that matter. Could be important.

Personally, I wouldn't run anything under an 850 in any BB jet boat if I could help it. But at 3800 RPM on a 454, you certainly aren't running out of carb. And that is where I'd be looking. As said, secondaries not opening, severe jetting issues, as lean as you are, and the very low rpm, I'd be swapping carbs. But I have a few extra around here to do that with. At the very least, run it, then look down it's throat, not running, and open the thing up manually and see if the squirters are working on all four corners at least, but you're look at a carb overhaul at minimum. 

Ray

Thanks Ray, so do you thing I should start with timing?

Your list of things to check is a short one.....


1- look for some ski ropes, duct tape, baseball cap, plus size woman's bra etc in the pump or on the pump shaft.

2- Check the timing at above 2500 RPM, I disagree with the lean statements at this time, did you hear a "popping" at WOT?

3- How fast do you feel the boat was going? GPS? are you sure the tach is running right? (be surprised how many times this is the issue).

4- Does the throttle linkage go WFO? Not with your hand at the carburetor, but with the foot on the long skinny pedal.... I have seen some carburetor installs have a linkage clearance issue with some cable mount brackets.



To add, you did not mention what ignition you are running, this has a gigantic influence on what the plug gap should be.....

GT

Also sorta slipped my mind, be careful with plug selection, it depends what heads you have, if you run a long reach plug where a short reach is needed, it can get expensive in a hurry....

GT

good luck tomorrow, try to keep a running tab on how it runs not just at wot but at all speeds you know how it starts cold and hot how it idels, 1/4 throttle 1/2 throttle 3/4 and full. hell bring a note pad.these are all things that will help you. have fun.

interested in what the problem could be.  i had like a 63/71 set of jets in my 650 carb and it ran awesome at WOT still... but it sputtered in between and my plugs looked lean.  i changed to 75/80 and now it runs awesome and the plugs have a nice little brown around around the insulators like they should.... is it a vac secondary carb?? do you even feel the secondaries kick in at all?  mine makes a very audible "weeeee" sound...

Your "weeeeeeeee" sound is likely a vacuum leak in the secondary diaphragm brother............shouldn't hear anything other than a little more "whoosh" sounds than normal if the scoop is facing forward. Otherwise, probably wouldn't even hear that.

Ray

Try the float levels, or maybe even a dirty fuel filter.


The beav