Idle and shifting problem intermittent

[bojango541]

According to the gauge on my dash, my boat idles at 200 rpm. After I give it some throttle and get up on a plane, I'll slow down and it only goes back down to 800-1000 rpm, much higher/faster than before. It is also much more difficult to shift it back into neutral or into reverse. If I turn the key off and turn the motor right back on, It idles much slower and the shifting problem goes away. Any ideas what is causing this?

Thanks in advance.

 

[bojango541]

Timing 5.8 OMC Cobra 1990

Timing 5.8 OMC Cobra 1990

I'm looking for the timing for my omc cobra 5.8l. Its backfiring like crazy when I give it throttle.

 

[bruceb58]

Re: Timing 5.8 OMC Cobra 1990

Re: Timing 5.8 OMC Cobra 1990

10 degrees with total advance of 30. Dwell is 29. Make sure you change your points and set the dwell before adjusting timing.

How are the other components of your ignition sysytem like wires, plugs cap rotor?

 

[bruceb58]

Re: Idle and shifting problem intermittent

I just commented on your other thread about timing. You may want to try disconnecting your tach. It can cause misfire problems if it is failing. The high RPM is what is causing your hard shifting.

 

[bojango541]

Re: Idle and shifting problem intermittent

I just commented on your other thread about timing. You may want to try disconnecting your tach. It can cause misfire problems if it is failing. The high RPM is what is causing your hard shifting.

Hi
I am bojangos Dad working on this boat, just want to pick your brain, we are also having other electrical issues, bilge pumps died and when put a volt meter on the wires I am only getting 6 1/2 volts fore and aft, also had an issue with lowrance, had to direct connect to battery to get it to power on. Could this all be connected? I am going down to dwell and time shortly, will disconnet tach also. Thanks

 

[bruceb58]

Re: Idle and shifting problem intermittent

Best thing to do is to start another thread. As far as the voltages you are reading, start at the switch and work your way backwards toward the device that has the low voltage. Also realize that you cound have a bad ground wire as well.

 

[bojango541]

Re: Timing 5.8 OMC Cobra 1990

Re: Timing 5.8 OMC Cobra 1990

Hey
Every thing I read and think says timing or ignition, but we did everything, timing, points, plugs, condenser, rotor, cap. When we cant get it to start, it helps if I manually open the choke flange and crack the rear throttle flange. It starts and idles fine.

Then we took if out for a test drive and if I control the carb by opening the rear flange manually I can get the boat to run fine without backfire, could this all have something to do with the electric choke mech. Again Thanks

 

[bojango541]

Re: Idle and shifting problem intermittent

Tried disconnecting tach, didnt help! Any other ideas?

 

[bruceb58]

Re: Timing 5.8 OMC Cobra 1990

Re: Timing 5.8 OMC Cobra 1990

Is the choke open when it is warm? Is it closed when its cold?

How does the engine run when it is finally warm? If it is backfiring through the carb, you have a lean condition.

 

[bruceb58]

Re: Idle and shifting problem intermittent

This is difficult troubleshooting the same problem in two threads. Maybe the mods can combine them.

 

[QC]

Re: Idle and shifting problem intermittent

Hey Bruce. OK, Merged to this one. If you need the title changed let me know. I haven't read the posts