Mercruiser won't idle.

[Rogerg]

23 ft.1996 Maxum I/O w/Mercruiser 7.5 l, 350 CI's engine. 2 barrel carb. (Rochester, I think).Will only run at 1900 plus rpms, less than that, dies. Has changed fuel filter and sprayed everywhere possible with "gum-out". Disconnected fuel line into carb. and sprayed there also. When changed fuel filter, filler it up with "gum-out", let it sit overnight and started it next morning. Nothing helps. Have heard some comments about vacumm leaks (how do one test for vacumm leaks???)and low speed fuel injector being plugged.
Any suggestions out there?? Thank You

 

[Bondo]

Re: Mercruiser won't idle.

ItSounds like it's time to Remove theCarb.,+ Rebuild it............

Squirting Gum-Out around a Carb. never really does much Good,........
Carb. Problems are Usually on the Inside,........
Get a Rebuilt Kit,+ Rebuild it........

 

[Don S]

Re: Mercruiser won't idle.

Did this problem just happen suddenly? or over a long period of time. If it did happen suddenly, did you find water in your fuel filter when you changed it? Did you dump it out and check?
How about a tuneup. When was it done last?

 

[KRS]

Re: Mercruiser won't idle.

and... when did it run good last? Last season or six years ago and it's been sitting since?

 

[KRS]

Re: Mercruiser won't idle.

oops... DonS already went there ^

 

[ziggy]

Re: Mercruiser won't idle.

have ya got yer oem service manual out yet. don't know about yer year manual, but my oem book has a trouble shootin guide givein ya symptoms and possible causes to check out.....they're pretty dandy books.......for your symptom, my book for a 75 has the carb as a possible problem for sure, float level, dirty carb, clean flame arester, or fuel pump pressure or as ya stated a vacum leak, as stated by dons, water in fuel. aslo primary and secondy ign. issues. connections, timein and dwell, cap and rotor, spark plug wires, low or uneven compression to name a few. what have ya checked out and confirmed to be o-key-doe-key..... keep in mind the info i'm providein is for my 75 engine. yers is much newer but may still have some of the same issues..........good luck........it seems the word to me is find out whats good and proper, then go find something else and keep lookin till ya find something ya don't like......startin with the basics......