4.3L won't idle

[kingc]

I have an '86 Rinker with 4.3L V6 and Mercruiser outdrive. The carb is a two barrel mercarb (one idle screw). It ran well when I winterized last fall, and I fogged the engine before storing. I was able to start it with little difficulty last week and let it run for about 20 minutes at 1000 RPM. Suddenly and without warning, it died. I tried to start again without success. When I disconnected the fuel line, I found lots of sediment in the filter. I decided to rebuild carb and bought a kit. The carb was filthy but cleaned up OK. I re-installed it and cannot get the motor to idle. I can get it to run (1000 to 2000 RPM) with throttle partially open and choke nearly closed. I have completely dis-assembled the carb and checked it twice since then with the same results. I have checked for vacuum leaks using the starting fluid method and found none. It acts like it's getting no fuel through the idle circuit but I have checked this over and over. I don't know what kind of pressure I'm getting from the fuel pump but it is filling the float bowl. Could this still be the problem? I've adjusted the float per the instructions in the kit. Could improper float adjustment cause this kind of problem. I don't know where to go from here?

 

[searay3]

Re: 4.3L won't idle

"When I disconnected the fuel line, I found lots of sediment in the filter." <br />"The carb was filthy "<br /><br />Check the fuel tank for contamination. Not sure how yours is configured, but it should not be too hard to see if it's full of junk. Filters would be a concern as would the fuel pump since the 'junk' made it all the way to the carb. Choke closed and throttle partially open says your starving of fuel.

 

[kingc]

Re: 4.3L won't idle

I completely drained fuel tank and refilled with fresh fuel. I also opened fuel pump and cleaned pump filter. With fuel line disconnected from carb, I can quickly fill a bottle with fuel by engaging the starter, so it seems I'm getting fuel to the carb.

 

[Bondo]

Re: 4.3L won't idle

It Sounds to Me,.. That the Carb. is Still your Issue................<br /><br />Due to Degradation of the Castings,.........<br />Rebuilding a Carb. is a 50/50 Crap Shoot.........<br /><br />If the Carb. is rebuilt in a Shop with an agitated caustic carb/parts Cleaner,+ is Blown Dry with Massive amounts of Compressed Air,.. Along with hand brushing All the passages,.....<br />And, Assembled by a Qualified Tech,..........<br /><br />Then your Odds will be slightly Better than that,.....<br /><br />My Guess is,... Your Carb. has a Tiny passageway, Somewhere,.. That's Packed Full.....

 

[SeaSkwurrel]

Re: 4.3L won't idle

Maybe the choke needs adjustment. See if it'll idle with the choke open further. Also, did you reset the idle needle screw? Should be initially 1 1/2 to 2 turns out, I think.

 

[rodbolt]

Re: 4.3L won't idle

on that 2bbl, all the idle fuel first passes through the main jets. remove them and remove the venturi cluster. carfully clean the passage from the main jets and the custer bowl area. then lets clear the idle pick up tubes on the cluster, thety are the two tiny tubes. they have air bleed holes at the top and clog easily.<br /> but you are describing a lean condition.use a single strand of copper wire and rod out the idle tubes.