454 magnum miss any ideas

[aitkenkingfish]

Mercruiser magnum 454 I am having ignition problems i have a miss that can easily be seen with a timing light conected to the lead from the coil to the distributor looks like it is once in the fireing order. I have changed the cap rotor points capasitor wires plugs. the tack has a jumps up and down, and i am having plugs fail in different cylinders. any ideas.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

If you have any ideas any input cant hurt.

 

[jlshields]

Re: 454 magnum miss any ideas

With the miss affecting the tach also, I'd look ing the primary circuit for a loose connection, pos. AND neg. John

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

thanks John I will check the conections.I appriciate the input.

 

[ob]

Re: 454 magnum miss any ideas

Check for anything that would interupt the signal voltage to coil.Loose connection,ground , short.Have you viewed distributor points opening and closing operation with cap off turning engine manually?Could even be a problem in distributor drive or lobes.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

I havent looked at the distributor will look and see if their is a bad lobe.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

definatly something in the distributor not shur what the advance is getting stuck when reving engine it will not return back to 8 degrees.

 

[Walt T]

Re: 454 magnum miss any ideas

What year is this?<br />If this is electronic, Check the #8 plug wire, see that it is not hanging doen by the knock sensor. That will wreak havoc. Otherwise, I bet its a module.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

I found a plug with the wrong gap fixed that. Turn out ive burnt up the impeller in the raw water pump.ill fix that and get back with you on the other problem.

 

[ob]

Re: 454 magnum miss any ideas

May very well be ignition module.Does the distributor have a mechanical or vacuum advance?

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

Its mechanical advance with points.

 

[johnkc]

Re: 454 magnum miss any ideas

a mercruiser 454 mag should have an electronic distributer ! if this really has points and a mechanical adv. i would get the right parts on it then see if your problem is still there.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

all fixed it was the distributor put the accel on and it fired right off no misses. thanks for all the help.

 

[ob]

Re: 454 magnum miss any ideas

Glad to hear you gotter up and runnin.Now you can have yourself a Merry Christmas.

 

[aitkenkingfish]

Re: 454 magnum miss any ideas

Thanks OB you have yourself a merry christmas.