1989 5.0 Cobra Stackfire

[johnfernen]

I have a 1989 19' bayliner with an OMC 5.0 Cobra. I have replaced the plugs, wires, dist. cap, condensor, points and have gapped the dwell to .017" point gap. My problem is that when I first give it throttle the engine wants to cut out and then it backfires with some stack fire. Not alot, but its there. It also runs rough at idle as well as throughout the RPM range. So I figured I would adjust the timing, only problem is that when I loosened the retaining clamp and bolt for the distributer, it wouldnt budge and I do not want to break it. Is there a trick to this? I also have no idea of what the timing should be for that year and engine. Any ideas would be greatly appreciated. Sorry its so long, but I hate when people dont give you enough info.

 

[Lou C]

Re: 1989 5.0 Cobra Stackfire

According the the manual I have the point gap should be .017, dwel angle 27-31 degrees, and for timing the spec is 5 BTDC using 86 octane gas and 10 using 89 octane.<br />Sounds like you should check spark plugs, and the wires for them as well. The cutting out when you open the throttle could be ignition or fuel related. I'd start with the ignition first, make sure all is well there, then you may need to check the carb settings.

 

[akriverrat]

Re: 1989 5.0 Cobra Stackfire

pbblaster, liquid wrench. strap wrench. sounds like too advanced timing or valve seating issue. are mechanical advance weights working properly, return springs intact?