Problems Changing Plugs 1990 Mercruiser

tashasdaddy

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Re: Problems Changing Plugs 1990 Mercruiser

daytonadan, aren't these guys great. still working on mine. Have to wait till the eagle s==ts
 

Don S

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Re: Problems Changing Plugs 1990 Mercruiser

Don S. a question for you about the mercruiser ignition thunderbolt 5. The ignition computer on the triangle mount, 1990 model, there's a solid black wire with a small ring on it. It's just dangling there.
Looks like Bondo got you headed in the right direction, Big thing here is you have a Thunderbolt IV (That is a 4) Not a Thunderbolt 5. There is a such thing as a Thunderbolt V (5) and it makes a lot of difference in troubleshooting and setting it properly.<br />The part that is mounted on that triangle plate is also known as an ignition module, not a computer.<br />Make sure the connections on the ignition module and the small harness are clean. They can cause all kinds of misfiring and no start when corroded.
 
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Re: Problems Changing Plugs 1990 Mercruiser

Yes,the diagram indicates the black wire goes to ground. You can ground it on the engine block, just make sure your ground is clean of paint and corrosion. Mine is grounded to the block along with a few other wires. Clean those other ring terminals while your at it with a wire brush,and then dab a little grease on them to slow the corrosion.
 

shelikesit

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Re: Problems Changing Plugs 1990 Mercruiser

It looked like it was grounded to the distributor. From the link above it's what I see.<br /><br />Is it possible that it goes with one of the distributor cap screws. Or should I just send it to the block as SeeRay stated.
 

Don S

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Re: Problems Changing Plugs 1990 Mercruiser

Merc just grounds them to one of the bolts on the triangular base. Just make sure the threads on the bolt and the riser are clean.
 

shelikesit

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Re: Problems Changing Plugs 1990 Mercruiser

Could that ground wire of been the problem from the very beginning? Something tells me that's where my no spark problem originated.<br /><br />Either way, everything is new now.<br /><br />Thank You!
 

Don S

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Re: Problems Changing Plugs 1990 Mercruiser

Why don't you hook it up and find out?????
 

shelikesit

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Re: Problems Changing Plugs 1990 Mercruiser

My motor is puring like a kitten, I can't believe the help ya'll gave me.<br /><br />For some reason it's seems nicely fine tuned, sorry but I'm in awe and lost for words.<br /><br />Unbelievable.............<br /><br />I just turned the key and it popped to life with what seemed like a "Thank you, I'm not getting junked yet relief"<br /><br />1990 Galaxy V-6 Mercruiser 22 foot cuddy with a walk around path and have less than 3500 in it, if I was a woman I think I'd cry right now :) ~<br /><br />Thank You So Much.
 

tashasdaddy

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Re: Problems Changing Plugs 1990 Mercruiser

proud of you Dan. hope i'm that lucky.
 

shelikesit

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Re: Problems Changing Plugs 1990 Mercruiser

Thanks!<br /><br />Impatience fried me in the beginning, losing that lousy demon fast is what saved me. I found out quick the more in a hurry I was, the further behind I got.<br /><br />From my experience so far I learned to take my time, get the connections 120% right and tight and hold your breath :) <br /><br />I took the boat out to Ponce Inlet, about 10 miles north via the intercoastal, and it ran like a dream. My only problem was idling after the motor ran for awhile. It never ran hot, never knocked or fluttered in RPM's, it actually ran and planed out unbelievably.<br /><br />I've never ran a boat before, my first boat I bought 6 months ago. A 17ft grumman canoe with 2 paddles. This was a BIG jump but well worth it. Not once in the whole trip tonight did I say, "I wish I bought a BIGGER boat". This boat was like having your own floating dock to move where you wanted to.<br /><br />It's a cuddy with a walk around yes, but the whole backend is wide open except for the motor cowl. I couldn't be happier or more pleased.<br /><br />I would think my idling problem getting to the dock may be from a deteriorating fuel pump. The carb ran way too well to start with it first. I was told by the sales lot the boat sat since August, when I finally got up with the actual owner last week he told me yeah it sat since August, last August 2004............<br /><br />Thanks again everyone, you walked this greenhorn through a major mess, pat yourselves on the back, my elbow's sore from reaching around all afternoon :)
 
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