View Full Version : Carbed 351 idle issue

06-05-2011, 12:07 AM
After ignition "tune-up" (plugs, coil, cap and rotor, points and condensor), boat runs strong, great hole-shot, nice cruise accelleration, but doesn't idle or "no wake" well. Actually "loads-up" because RPM's are so low, peters-out and dies.

Would this be a carburetor idle issue or timing/point gap (.019 gap) issue? I did not adjust timing at all.

Was gonna mess with the idle screw after getting back to the dock but thought I'd check here first; not a fan of messing with carb adjustments.

I will say this, prior to the new parts, the boat went thru no wake pretty fast; I usually had to do the ol' forward-neutral-forward bumps so not to create wake. (Although NOT creating wake is always tough with the TriStar hull design)

1990 TriStar, 351 Indmar, Holley carb

06-05-2011, 08:37 AM
People here will tell you to upgrade to electronic ignition which is probably a good move but in the meantime definitely check the timing which you should do either way (I am not necessarily saying that is the issue but it is very easy to check and I am a fan of verifying the easy things first before trying the hard things). I don't remember the points gap but you can check with dwell meter which should be 28 degrees I believe (timing at idle should be 10 btdc).

What is your idle rpm? When everything is working well you can get them to idle too low such that it really doesn't run when put in gear in which case you simply need to pick it up a bit with the throttle position set screw (this isn't a risky "carb adjustment"). I wouldn't mess with the idle mixture screws until everything else is verified (my personal experience with the idle mixture screws is that they have never solved a drivability issue... Not saying they can't just saying they haven't for me).

06-05-2011, 08:57 PM
First look at what you have changed before working on things you haven't. When you replaced the points, did you use a dwell meter to set them to spec? Using the point gap will get you in the ballpark, but only right on if you are lucky. This is most likely your problem.