not good at low RPM

canyonken

Seaman
Joined
Jun 23, 2008
Messages
58
1996 SeaRay 175XL with the 4.3 liter v6 genII+. 2 barrel mercarb. Thunderbolt IV ignition.
I recently changed all plugs, new cap/rotor and new plug wires. Gas (10 percent ethanol) is no older than 5 weeks old.
Boat starts great. It seems to have trouble with rough idle and sporadic RPMs and a few stray backfires when trying to idle around the marina or no wake zone. Anywhere from 600 to 1200 RPM range. You have to stay on the throttle to keep it from stalling now and then. Once you give it a good amount of throttle and get up on plane - it runs perfect. No problems. Engine runs real smooth at this point. I run it at 3000 RPM - it can go all day with no real problem. Back off throttle and idle round and it seems to run rougher and backfires every now and then. Any help ??
 

rthomas

Petty Officer 2nd Class
Joined
Nov 9, 2007
Messages
155
Re: not good at low RPM

Sounds like the idle passages in the carb might be plugged, or someone turned the adjustment screws in to far, if thats not it you might have a vacuum leak.
 
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