Mercruiser runs great at cruiser but dies at 1500 rpm or less

[Mlkman]

I have a 1994-95 Mercruiser 5.7L MIE 350CID 260HP. Do to bad gas and water the engine would not run correctly so I replaced the carb with a factory rebuilt weber(exact same model). Ran the boat on a long trip and it ran great until entering the harbor where it stalled out below 1500 RPM. Engine will start eventually when warm but will continue to stall at low RPMs. I think it was flooding since after it would stall the 1 venturi would continue to drip and there would be a puddle of gas on the secondaries. Any suggestions are appreciated.<br /><br />Thanks.

 

[Bondo]

Re: Mercruiser runs great at cruiser but dies at 1500 rpm or less

Do to bad gas and water the engine would not run correctly

Yep,<br />And now your New Carb has a Plugged Low Speed Circuit..........<br /><br />I'm Guessing that your Original Problem is Still a Problem....................

 

[Mlkman]

Re: Mercruiser runs great at cruiser but dies at 1500 rpm or less

Thanks Bondo. I rebuilt and cleaned the original carb and think I solved the idle problem but it still seems to run a little rough. Another issue now is that at idle, I put it in gear and the RPM's drop from 800 to 500-550. Pretty drastic since before the idle problem it would only drop about 75-100 rpms maybe. The tranny (Hurth 630A starboard side) also chatters now like it is slipping (Checked the shafts and they are not fouled). Did I lose a cylinder?

 

[Bondo]

Re: Mercruiser runs great at cruiser but dies at 1500 rpm or less

For the Idle Drop,<br />I'd look for a Vacuum Leak...??<br />Or further Carb Adjustments........<br /><br />I Can't Help at all with the Tranny.......<br />Never been there........

 

[Mlkman]

Re: Mercruiser runs great at cruiser but dies at 1500 rpm or less

Thanks Bondo.<br /><br />I did a little checking on the vacuum hose but I will inspect further. I read that the tranny will chatter if you lose a cylinder. Any truth to that? I am hoping it is a bad valve or distributor cap.<br /><br />Thanks