1994 5.7 mercarb question

[B Rad G]

1994 Monterey 206. 5.7 with 2bbl mercarb TB IV. I have this thing running really well, save one problem. Have replaced plugs, rebuilt carb, soaked carb and blown everything out. Set everything to spec. Set timing and idle. Dead on. Starts up with ease and idles at 750 like a clock. Will accelerate without hesitation when I throw it down. But if I accelerate slower, just easing up, it wants to die around 1100 rpm. If I pull back it keeps running. The accelerator pump linkage is in the middle hole on the arm. Should I try moving it, or is there something else that I could have missed. I'll try moving the arm to see if it changes anything, but was wanting some other ideas if possible. Thanks in advance.

 

[achris]

What happens if you goose it, then pull it back to try and sit on 1100rpm? If it still tried to die, then you have progression hole problems....

Chris...

 

[wellcraft-classic210]

As you move from Idle to higher RPM's the fuel is delivered through different sources ( Idle circuits vs Venturis )

Sound like your venturi's may not be delivering fuel at the lower end of their range. ( 1100 rpms )

 

[achris]

As you move from Idle to higher RPM's the fuel is delivered through different sources ( Idle circuits vs Venturis )

Sound like your venturi's may not be delivering fuel at the lower end of their range. ( 1100 rpms )

At 1100rpm in neutral, it won't be on the main circuit (venturies), it'll still be running up the progression holes...

One thing that would easily point you in the right direction. Fatten up the idle mixture (make it richer) and see if that helps... If it does, then you need to pull the carb again and clean the idle and progression circuits. High pressure air blown in both directions is usually all you need..

Chris....

 

[B Rad G]

Hey Chris. I took your advice and just removed it and blew out all of the passages again. Made a huge difference. Thinking maybe something made it thru the filters and clogged something up. Appreciate all of the advice. Owe you a beer or brown liquor or whatevers your poison.

 

[silverseal99]

I had a similar issue with a 5.7L Mercarb. Teflon tape from NPT fitting at the fuel filter degraded and clogged the low speed jets. Reputable local carb mechanic told me "No Teflon tape! Paste only!"