mercruiser 3.0L 140hp won't idle below 1800

[Jeremy1974]

I got a 73 starcraft with a 140hp 3.0 merc and can not get it to idle below 1800 with out stalling. If i slap the choke it will prolong it from stalling but it is chugging bad , and then it will stall.the motor had been rebuilt and the carb was to. I sprayed it with soapy water to check for vacum leaks but did not make a diffrence.

 

[tommays]

Re: mercruiser 3.0L 140hp won't idle below 1800

i dont no if slaping the choke means you are closeing it or opening it<br /><br />if it is opening it needs to be repiared<br /><br />if closeing it helps the motor run it sounds like you idle circut is cloged in the carb<br /><br />need more info on what you mean<br /><br />tommays

 

[bomar76]

Re: mercruiser 3.0L 140hp won't idle below 1800

Originally posted by Jeremy1974:<br /> I sprayed it with soapy water to check for vacum leaks but did not make a diffrence.

Uhh...hate to break this to you, but the the intake system on a non super or turbo charged engine (like yours) operates on negative pressure. You could have a vacuum leak big enough to stick your head in and it's never gonna show up as bubbles with soapy water. <br /><br />You can CAREFULLY use aerosol carb cleaner to look for vacuum leaks (have fire extinguisher ready).<br /><br />My guesses?<br />One or all of these:<br /><br />Carb never adjusted after rebuild<br />Carb rebuild screwed up<br />Bad fuel