Just cant figure this out...

[Cup420]

Per a few mechanic, friends of mine, I put two cans of marine seafoam in my tank and ran the absolute stew out of my boat the other day. I think I drove a total of twenty three miles straight. Ran the motor as hot as I possibly could and kept running on full throttle. She idols beautifully, but when i'm trying to get on plane, she starts bogging down around 4000-4500 rpm. She WAS staying there for about two minutes before heading up to 5000. That actually improved. But I still have the bog and the ever so slight push push...push push. Fuel filter is clean, spark plugs are new, getting spark on all four cylinders, compression is good, carbs we're rebuilt last february, fuel plump was replaced last february, coils were replaced last february, maintenance has been kept up 100%. Vacuum lines have been checked and are strong, fuel lines are all brand new, as well. I really don't want to go through the job of tearing those carburaders down again.But I guess if I have to I will. Also I have ran nothing but ethanol free in this boat, since i've had it. Yamaha 50hp 2003 4stroke

 

[Captain of the Double G's]

Correct spark plugs ?

 

[Chris1956]

When she bogs, hit the choke button for 1/8 sec and see if she picks up. If so, it is some sort of fuel delivery issue. If not, maybe an ign issue?

 

[boscoe99]

No choke in a 2003 Yamaha F50.

 

[Cup420]

Correct spark plugs ?

Yes

 

[Scott Danforth]

no such thing as a mechanic in a can.

 

[Chris1956]

So no choke on that carb? Interesting.

 

[Cup420]

So no choke on that carb? Interesting.

Nope

 

[jlh3rd]

When she bogs, hit the choke button for 1/8 sec and see if she picks up. If so, it is some sort of fuel delivery issue. If not, maybe an ign issue?

It does point to an intake leak/ temporary lean condition or some kinda restriction in the idle to main fuel flow.

I'm unfamiliar with outboard ignition advance, but needs to be checked.