Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

[eufalamatthew]

I posted a message the other day but for some reason it never showed up. Engine was running great only had to replace starter since I bought it last year. Always started. Now it won't start. I have found there is no spark jump at coil to center wire of cap. I have looked for a kill switch with a lanyard eyelet but haven't found it (Boat Model is Cheetah)<br /><br />Check dc volts at coil and have 12v on both + and - terminals. At the modulator? (where the coil and distributer wires come from) I have 12v at + & - coil wires. The + wire has next to it a white wire with a colored stripe and it shows 8v but not on corresponding wire wire by the - coil wire. OK now what is the problem?

 

[Don S]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Here is a Thunderbolt IV troubleshooting chart from the Merc Service manual.<br /><br />

 

[Trent]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Ok since you are a Eufaula Lake boater I will try to help? <br />Here is a flow chart for your IGN system...<br /><br /> web page

 

[Trent]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Don.. Ya beat me..

 

[eufalamatthew]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Gee Thanks you two for the help! (I wish I had not missed the second u in Eufaula in my user name Trent.) Hello Don in Alaska!<br /><br />Can either of you supply me with the correct coil number like a Borg/Warner #? I got one from the auto parts house (In the boat now as I write) or any other correct coil number my parts house can cross reference to make sure I have the right coil? I put it in when I first had the problem but it didn't make a difference.<br /><br />Also How much should an Ignition Module cost and where can I get it if it happens to be the problem. My local Egomaniac Boat Brainiac seems to think it is a Overboard Kill Switch which I cannot find. The boat is a 94 Cheetah<br /><br />Tanx Heaps O-B-Juan(s)<br /><br />Matthew <br /><br />"Did you know Oklahoma has more shore line than any state including Alaska? (Someone told me that)

 

[Don S]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Well, I don't have a clue what a Cheetah is or looks like, but an overboard kill switch is common on lots of boats. Especially open boats. It's were you hook your safety lanyard in to kill the engine incase you get thrown overboard or injured and fall down. It just kill the ignition.<br /><br />Here is link to one place to get genuine OEM parts and part numbers.<br /><br /> http://dougrussell.com/partscatalog/collections/index.cfm?fuseaction=collectdetails&colid=04 <br /><br />PS: If you go to the top of the page and click on "My Profile" then "Edit Profile", you can add that missing U to your name.

 

[eufalamatthew]

Re: Mercruiser Alpha 1 Thunderbolt IV no Spark at coil

Thanx Don