1997 Mercruiser 3.0LX dies when choke opens

[CPro]

I have a 97 Mercruiser 3.0 LX with an Alpha One. The boat starts great...fires right up. I pulled the flame arrestor off this evening so I could watch what happens. The boat runs fine with the choke closed, but once it opens up you have to run at high RPMs or it dies.

I made sure everything was tight...all hose fittings, all carburetor fasteners, etc.. I'm thinking fuel pump, but was interested in what you guys may think?

I replaced all the ignition components last year. I also did the head gasket last year. It ran great for awhile, but by the time I put it away for the winter it was exhibiting this behavior.

Thanks in advance for any thoughts.
Trev

 

[achris]

Sounds like a blockage in the carburetor idle circuit. Pull carb, strip, clean, reassemble and adjust....

Chris.....

 

[CPro]

I will try that. Thank you Chris!

 

[CPro]

I cleaned the carb up and I still have the same symptoms. Next step is replacing filters and also the anti-syphon valve. I've read that this can cause issues.

 

[Mad Props]

When its full choke, the motor is running rich, which means its getting more fuel.. Once the choke opens, it should be getting less fuel, so going on that basis, the fuel filters and anti-siphon valve should not be the issue. Plus its running okay when you rev it up.

Don't just start throwing parts at it without breaking down the basics..

Did you do a full carb rebuild or just spray carb cleaner on it?

 

[CPro]

Replace the inline filter before the carb as well as the water/fuel separator and problem solved!

 

[Bt Doctur]

cleaned the carb up and I still have the same symptoms

You COMPLETELY DISASSEMBLED the carb and put it in a ultrasonic tank?

 

[Mikey N.C.]

Carb. Sounds like. Does metering block still have cap plugs ?

 

[CPro]

I don't have an ultrasonic tank...but I did disassemble the carb, sprayed it with carb cleaner, wiped it down, and reassembled it.

After replacing the fuel/water separator and the inline filter at the carb, the problem was solved. It's running great now.

 

[Scott06]

I don't have an ultrasonic tank...but I did disassemble the carb, sprayed it with carb cleaner, wiped it down, and reassembled it.

After replacing the fuel/water separator and the inline filter at the carb, the problem was solved. It's running great now.

You may want to check your fuel water sep after a few hours running as there’s likely a reason it clogged, might have never been changed, might be junk in fuel tank.

 

[Bt Doctur]

I don't have an ultrasonic tank...but I did disassemble the carb, sprayed it with carb cleaner, wiped it down, and reassembled it.

Let me rephrase, You completely disassembled it removing the jets, venturi cluster, needle and seat, throttle shaft, cleaning passages with a welding cleaning tip selection?

 

[Bt Doctur]

https://www.youtube.com/watch?v=JHjjAz367Ng

 

[achris]

I don't have an ultrasonic tank...but I did disassemble the carb, sprayed it with carb cleaner, wiped it down, and reassembled it.....

Did you at least blow all the jets and passages out with dry compressed air? And let the carb soak in the cleaner overnight?

And by compressed air , I mean at least 60psi. Not some blow not-very-hard 'air duster' in a can.

Chris........