omc 460 timing

[thmlrmg]

hey guys, boat is still not running, i have went through the timing procedure from my manual 10 times and still nothing. i am getting spark and gas still it doesn't attempt to fire. does anyone know where the rotor should be pointing when the #1 cylinder is at tdc. right now i have the #1 at tdc and the rotor is pointing (physically pointing not inside the cap) at the #6 cylinder with the back part of the rotor pointing at #1 cylinder. when i put the cap on the rotor is dead at the #1 tower. when i crank it i see spark but no fire????? wtf man

 

[thmlrmg]

Re: omc 460 timing

oh by the way i am getting an orange spark when i ground the plug to the block. is this caused by low battery and can the points and condenser cause this???

 

[kwoolard]

Re: omc 460 timing

With the number one cylinder at TDC the rotor should be making contact with the number one position on the cap, theoretically. The timing is advanced a few degrees depending on the engine, apprx. 8-12 degrees.

 

[kwoolard]

Re: omc 460 timing

That is TDC on the compression stroke! One way to check is to pull the number one plug, replace with your thumb and bump the engine over until you get full compression. <br /><br />Another way is to pull the valve cover and note when both the exhaust and intake valves are closed after the intake valve was opened.

 

[thmlrmg]

Re: omc 460 timing

we did all that and we know we are at tdc and the rotor inside the cap is on #1 cylinder but the motor doesn't even attempt to fire. we are getting orange spark from the plug. i am wondering if we don't have good enough spark??? what do ya'll think??

 

[rattana]

Re: omc 460 timing

Orange spark is too weak, It should be blue/white. What is the voltage going to the small positive wire to the coil and the block when you are cranking? What is the voltage from positive on the coil to the block when the key is in the run position? You either have a weak coil, points problem or low voltage to the positive primary wire on the coil(+12VDC wire on the coil) Do you have points or electronic ignition? <br />A quick test to check your ignition circuit is to connect +12VDC wire from battery to the positive on the coil and try starting it. If it starts then you can trace that part of the circuit to find the problem. To stop the engine disconnect the temporary wire to remove the run command to the ignition, and turn key off. Don't leave the 12VDC connected for more than a few minutes as it will burn out your coil.

 

[thmlrmg]

Re: omc 460 timing

we have 11.6 on the + side of the coil when the key is on i don't know about in the start position. we tried running a direct line from the battery to the coil + side and still didn't start. maybe the points???

 

[rattana]

Re: omc 460 timing

Can you remove the cap and crank the engine over to check the point gap, disconnect the positive wire to the coil so there is no sparks. I don't have the specs for a 460 but the points should open about .016"-.019" (.41mm-.48mm)A quick way but not very accurate is to use the thickness of a match book package to set the point gap. A dwell meter would set the gap up accurately but feeler gauge is fine. Verify that the condensor is connected. They can fail but not that often. Also look at the metal tab on the end of the rotor where it mates with the cap and ensure there is no corrosion on it. You should replace the cap, rotor, points and condensor if you see any wear or damage.

 

[rattana]

Re: omc 460 timing

Also 11.6VDC is a little high in the run position and may have burnt your coil. I would look for 9VDC +/- one volt. We can deal with that once it is running.