Soft and Supple
 

Now that I have your attention, get your minds out of the gutter. I am still having fuel issues so I replaced the primer bulb and line, hence the soft and supple part. I am trying to eliminate as many things as possible. I am running from a portable tank connected directly to the fuel pump. I replaced the spark plugs again. She started up and ran like a champ from the dock, then... bogged down and would not go faster than a troll. I ordered a fuel pump last night thinking that may be the issue at this point, any other thoughts.

1988 Evinrude 120 V4 looper (VRO disabled by Skools, of course)

What I have done so far
Run concentrated mixture of SeaFoam, 1 can with 4 gal fresh gas. Cleaned out alot of crap but not the issue.
Replaced plugs ( Champion L77jc4), .030 gap
Replaced fuel line and primer bulb

what kind of primer bulb did you install? Only use one supplied by an engine manufacture (I use Bomb stuff). I've thrown a bunch of new sierra/moeller/etc... in the garbage. Yamaha makes the best one($$), the mercury and bomb are identical, with the bomb being a little cheaper in price. Beyond that, check the fuel pump diaphram

The bulb / Line I put on was a valmar brand.
I have no issues opening the fuel pump to check the diaphragm, what am I looking for?

easiest way to see if your fuel pump is bad is to start squeezing the primer bulb as if you were priming the engine while the boat is underway. By do that your hand will be acting as the fuel pump. In other words, if the boat can runs while you are squeezing the primer bulb then it stops when you stop. It should be the fuel pump.

make sure the vent on the portable tank is open, like ct says, is ball collapsed or still firm?

Vent is open on portable tank. Bulb is softer but not collapsed, I know it isn't supposed to stay firm. Here is the pump removed and then opened. I don't see any trash and the rubber looks good to me. Other than what you see, I have no clue where to go from here.

I may have missed it in previous post, but are you SURE problem is fuel or fuel delivery issue?

cterrebonne's description of squeezing the bulb got me 15 miles back up the lake one day when pump failed...

No, I am not SURE of anything except it will idle, not run under throttle.

Has this engine sat for any length of time? It only takes 2 weeks of sitting with gas in the carbs for fuel to varnish and plug your jets. And just because it idles doesn't mean your carbs aren't plugged and varnished. There are 3 different fuel circuits in your carbs, and 2 of the 3 can be plugged and it will still idle but fall flat on it's face when you hit the throttle.

yes it sat for about 18 mos. I tried to purge as much fuel as I could by running it til it died.