Engine died down at high RPM.

[tsubaki]

What boat do you have?
Better yet where are the fuel tank(s) located?
Almost sounds like a split at the top of the pickup tube in the tank.

[tsubaki]

Air in the line could be a number of things.
Usually it will straighten out by pumping the bubble till it's hard.
If no fuel leaks or smells are evident and the air persists, you may have to check the pickup tube coming out of the tank for a split.

[mushman]

It's a 1986 steplift, the tank is in between pedestal and back to back seats in the front of the boat right before you step into the cuddy.
I was using a clear hose to get the old gas out and I kept getting so many bubbles in there it would kill my syphon flow.
I had it attached to the fuel line before it went into the fuel filter under the cowling.
I didn't clamp it, but it was a real tight fit, and I didn't see bubbles comming in from around the seal.
How would I check the pickup tube for a split?.

[tsubaki]

If you're sure there aren't any loose connections between the tank and the point where you're getting the bubbles, remove the hose at the tank and try the same thing at the fitting at the tank.
Useing the clear hose helps a lot.
I'm sure this is going to involve removing a floor hatch and a lot of other crap.
Try everything else first, replacing filters, checking for loose connections (there should be a gas leak)
If you have to access the tank, might as well inspect the fitting and tube by removing it. Last resort.

[tsubaki]

The pickup tube rests down below the place where the fittings tighten into the tank and have a filter.

The fittings have a ball valve in them to reduce siphoning.

Try everything else first.

[steplift20]

i would check each wire see if your getting spark
the prblem is you can be getting spark but one side can be wee=ak
also check the vent
while your driving and the engine cuts down take the fuel cap off and see if it returns to normal if it doesnt its not the vent

[THEFERMANATOR]

First things first, get you a helper and go for a ride. Have somebody pump the primer while it is acting up and ses if that clears it up. If it doesn't change anything, swap the powerpacks from side to side. Then see if the wet plugs clean up and the good ones look wet. The simplest ignition diagnostic tool is a spark tester with an adjustable gap in it, you can get them from any auto parts store. Open the gap up to at least 7/16" and check each wire idividually. If you have GOOD bright spark at each cylinder then most likely it isn't an ignition problem. The proper tool is a peak reading volt meter. MAKE CERTAIN THAT IT IS A PRV STYLE METER! Just because your meter says it will measure peak voltage, doesn't mean it will read correctly. My DVOM would read barely good on some systems and great on others, but with the CDI PRV adapter it reads consistent voltage. If you don't have access to one, then try swapping the packs from side to side. This will help you to narrow it down if it's a pack or not. The PRV eliminates alot of the guesswork though.