rough idle

[Tommer]

I have a Volvo 3 liter stern drive. Last year the idle was very rough when the engine hits about 1000 rpms everything ran fine. Other than changing the oil and plugs etc. this engine has been perfect for me. The last couple of years we have not used the boat much and I am thinking the carb may have some varnish buildup. What is the best way to clean out the carb as I am planning to put the boat in the water this week any ideas and or suggestions would be appreciated.

 

[sandkicker]

Had an issue with a 2BBL carb on my 5.7 MERC... started out as rough idle, then progressed to "would not run under 1500 RPM PERIOD!" (docking was fun!). Tried all the "magic potions"... to no avail. Ended up removing the carb from the engine and dismantling it totally. Found HARD whitish deposits in carb bowl. Removed the venturi block and found that one of the jet tubes was mostly blocked with a very hard deposit. It took a straightened out fishhook to chip the deposit enough for a piece of #24 AWG copper wire (old house phone wire) to finish the job. The old "soak and blow" method of carb cleaning may not work in all cases these days.