1982 Mercury BlackMax - will not accelerate

[ironmachineus]

150hp 1982 v-6 Mercury. Engine idles fine, and boat moves fine at slow speed. However, if you accelerate beyond 1/4 throttle, it bogs and coughs and won't accelerate. It doesn't die, but it just sits there bogging down. Occasionally, it will accelerate correctly, but this only seems to happen right after launching the boat. I took it in to the marina, and the said both power packs were bad (they tested voltage or something), and replaced them to the tune of $500. They said compression was fine, and consistent at 110 in all cylinders. I launched again today, and the first run was fine, but after fishing for a while it's now doing the same thing again (bog and won't accelerate). Any help would greatly be appreciated. Thanks!

[The Whale]

Fuel delivery ? Examine from the tanl to the cylinders. Partial plug restricting extra flow on demand maybe ? Odd though you get an occasional "good run". :confused:

[ESOX]

Change the plugs, regardless of how they look. Heat increases electrical resistance, one bad plug will make her bog like a dog after it's warmed up, while the others will keep her from stalling.
Also run a strong dose of Seafoam through it.

[roger23]

Check your fuel lines .fuel pump ,and fuel tank vent and vent hose for obstructions

[ironmachineus]

Mechanic says must be the stator. Gets heat soaked and the high speed coils don't conduct properly. Says the bad powerpacks may have ruined the stator, so they needed replacement anyway. Any thoughts?

[Sportfishermans SVC]

Possible, seen it happen. Sucks when it does if you are the mechanic because no matter what you do the customer feels like something is fishy. That said, make sure something isnt, check your fuel like everyone is saying because you could have a little debris floating in your bowls that is sucking into the jets as you run, and then floating free after it sits a bit, seen stranger things happen. Otherwise Welcome to the World of Mercury :)

[svw99ta]

I have had the same problem with my 150 black max. Someone suggested those triggers to me too, so I bought a set off Ebay, plus all the coils and the wires. I now have spark on all 6 cylinders, but it still does it. With 2 people in the boat, it will barely get on plane, and its only got a 24 pitch prop, so it shouldn't be that hard. I am about ready to sink this damn champion!:help:

[ironmachineus]

Svw99ta,
What exact problem are you having? It doesn't sound the same as mine. I can't go faster than idle, so I'm nowhere near planing out.