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Idle RPM and Hunting

mcastellitto

New member
I have 671 TIB´s with 350 hours on them since majored. I purchased the boat last fall and all has been well. I have put about 50 hours on it this season, with the majority of those hours at idle rpms´s (550- 575) trolling for rockfish. The last two times out I noticed the idle rpm on the starboard engine drop just below 500 and the engine hunts ever so slight at startup. Once I give it some fuel it levels out and stays constant but still just below 500 rpms. The port is steady at about 575 and you actually can hear the difference.

Additonaly, after an hour and half run home last Sunday this same engine (starboard)stalled as I approached the dock (after a +/- 10 minute idle back into the creek) but started right back up with a push of the start button.

Any ideas on where to start looking for a problem? All fuel filters were changed 50 hours ago
 
You might want to take off the valve cover and carefully inspect the movement of each injector rack to see if something is hanging up there. Any hunting is a sign of unequal movement/adjustment of some sort.

Check the buffer screw jam nut to see if it might have backed off. Most tune up guys get the last few rpms on an engine with the buffer and that may be where yours went. Although, if that is the case, the tune is not a good one. When I did that every day for a living, I could leave the buffer backed all the way out if I nailed the rack adjustment. Don't mess around too much with that if you don't know what you're doing.

Your issue may be in the governor. Could be a low speed weight hanging up or a spring getting weak. Either way, you need a qualified tech to go mucking around in there. Good luck.
 
just as jgmo spoke on the last post. Need a professional to set your idle screw as well as buffer screw on your governor,your idle screw holds a steady idle and your buffer screw stops the hunting and also stops the rack from going to the kill position. just make sure they know what there messing with, alot of mechanics after they overhaul an engine do not reset the fuel rack or governor( just parts changers) GOODLUCK!!!
 
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