78 6hp: Dies When Throttled Down, Specific Symptoms Inside

[gnarleygnu]

As stated in title, I have a '78 6hp. I've searched the forums extensively, I have the manual but am still super stuck!

Problem: runs rough and lacks power, dies if throttled down to idle, choke taken off or transmission engaged.

This is the specific starting procedure I have to use to get it running which works every time:

1) Idle adjust at lean (all the way counterclockwise)
2) Choke 100% out. 2nd pull motor stutters.
3) Choke 50% out. 2nd pull motor fires up.

As I'm going through the starting ritual I can see a bit of fuel collect and drip out of the carb intake. Don't know if this is normal.

Seems like a fuel problem to me. I changed the old-ish fuel out today and swapped it for fresh non-ethanol fuel.

Fuel filter clean

plugs replaced, gapped.

Carb rebuilt to try to solve issue, no change. One caveat: it was my first carb rebuild, while I blew out all the jets with compressed air and I made sure all the parts were as clean as possible I didn't soak the parts in solvent which I now know I should have. Carb parts looked super clean when I pulled everything apart, other than the float which was really torn up and the float valve which was a bit worn both of which I replaced.

fuel line bulb is firm throughout operation

I feel at a loss here, I don't have the diagnostic skills that I'd like (yet) and thought some of you experts could give me a hand tracking down this problem.

Thanks in advance!

 

[gnarleygnu]

Re: 78 6hp: Dies When Throttled Down, Specific Symptoms Inside

Even after all my site searches I didn't find this fellow's post: http://forums.iboats.com/showthread.php?t=393967 which is sounds extremely similar to my issue...

 

[AlTn]

Re: 78 6hp: Dies When Throttled Down, Specific Symptoms Inside

did you remove the core plug on top of the carb and clean the 3 small holes found in the well there?...you'll also see the tip of the idle mixture needle there....these provide your idle circuit...once your mixture needle is correctly set, you won't have to mess with it to start, and rarely have to mess with to idle properly

 

[gnarleygnu]

Re: 78 6hp: Dies When Throttled Down, Specific Symptoms Inside

No, I didn't pull the core plug. i think I might give it a shot. However, wouldn't that just cause an idle issue, and a lean one at that? The motor seems to be getting too much fuel at all times, although if I take the choke off it dies.