Hi all. I have 92 merc 454 with Thunderbolt IV ignition. I'm having a
starting problem, no spark, when the spark is there she loves to fire
up. Could a bad ignition sensor cause intermittent problems? Or is it
a, when it's dead it's dead kind of thing? Coil, plugs, cap, sensor
wheel are new. It has been pretty cold and wet up here in the North
East. I'd like to hear it's a bad ground or connection somewhere but
things really don't look that bad, I have not cleaned every connection
yet but some adivce on where to really focus my attention would be
great. I have only been one person for another day or two so it has
been tough to do a lot of tests requiring two. I'm just starting to go
a little nuts I mean she runs one day then nothing for two, then runs.
When she's running she runs great. Thanks. K

wrote in message
ups.com...
Hi all. I have 92 merc 454 with Thunderbolt IV ignition. I'm having a
starting problem, no spark, when the spark is there she loves to fire
up. Could a bad ignition sensor cause intermittent problems? Or is it
a, when it's dead it's dead kind of thing? Coil, plugs, cap, sensor
wheel are new. It has been pretty cold and wet up here in the North
East. I'd like to hear it's a bad ground or connection somewhere but
things really don't look that bad, I have not cleaned every connection
yet but some adivce on where to really focus my attention would be
great. I have only been one person for another day or two so it has
been tough to do a lot of tests requiring two. I'm just starting to go
a little nuts I mean she runs one day then nothing for two, then runs.
When she's running she runs great. Thanks. K

Could be a bad sensor, or a bad tach, or a bad deadman switch ?
Jim

Bravo 1

wrote in message
ups.com...
Hi all. I have 92 merc 454 with Thunderbolt IV ignition. I'm having a
starting problem, no spark, when the spark is there she loves to fire
up. Could a bad ignition sensor cause intermittent problems? Or is it
a, when it's dead it's dead kind of thing? Coil, plugs, cap, sensor
wheel are new. It has been pretty cold and wet up here in the North
East. I'd like to hear it's a bad ground or connection somewhere but
things really don't look that bad, I have not cleaned every connection
yet but some adivce on where to really focus my attention would be
great. I have only been one person for another day or two so it has
been tough to do a lot of tests requiring two. I'm just starting to go
a little nuts I mean she runs one day then nothing for two, then runs.
When she's running she runs great. Thanks. K


Check if you have voltage to the system when the motor does not want to
fire.

The Thunderbolt ignition is pretty much bullet proof. Intermittent no
function unlikely. More like shift interrupter prob or connections/power
to coil.
JR

wrote:
Hi all. I have 92 merc 454 with Thunderbolt IV ignition. I'm having a
starting problem, no spark, when the spark is there she loves to fire
up. Could a bad ignition sensor cause intermittent problems? Or is it
a, when it's dead it's dead kind of thing? Coil, plugs, cap, sensor
wheel are new. It has been pretty cold and wet up here in the North
East. I'd like to hear it's a bad ground or connection somewhere but
things really don't look that bad, I have not cleaned every connection
yet but some adivce on where to really focus my attention would be
great. I have only been one person for another day or two so it has
been tough to do a lot of tests requiring two. I'm just starting to go
a little nuts I mean she runs one day then nothing for two, then runs.
When she's running she runs great. Thanks. K



--
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Home Page: http://www.seanet.com/~jasonrnorth

wrote in message
ups.com...
Hi all. I have 92 merc 454 with Thunderbolt IV ignition. I'm having a
starting problem, no spark, when the spark is there she loves to fire
up. Could a bad ignition sensor cause intermittent problems? Or is it
a, when it's dead it's dead kind of thing? Coil, plugs, cap, sensor
wheel are new. It has been pretty cold and wet up here in the North
East. I'd like to hear it's a bad ground or connection somewhere but
things really don't look that bad, I have not cleaned every connection
yet but some adivce on where to really focus my attention would be
great. I have only been one person for another day or two so it has
been tough to do a lot of tests requiring two. I'm just starting to go
a little nuts I mean she runs one day then nothing for two, then runs.
When she's running she runs great. Thanks. K

Have had a problem like that--the Mag pick-up up sensor in the distributor
was cracked. Would work part of the time. Pull the cap and check that--can
look OK till you actually wiggle it. Good luck! Dan

Hi, thanks. It's funny you say that, last weekend I replaced the cap
and wheel and gave the sensor a little wiggle and cleaning, started
right up. Next three days, nothing. Last night I went ahead and
replaced the sensor, fired right up. The old one looked awful. So I
have new cap, wheel, plugs, coil and sensor, I hope she fires back up
tonight. Thanks again