Merc 4.3 I/O thunderbolt V issue please help!

Joined
Aug 6, 2012
Messages
5
iBoaters, Gotta say I love this site! I don't post much here but this is not my first rodeo and I've tried everything within reason to fix my issue. I've got a 2000 Crownline 19' with Merc 4.3 Alpha one and thunderbolt V. I have no spark...here's the background and what i've done: -ignition switch was working off and on...sometimes I'd turn key and get nothing from the starter. I would turn key back to off and back on and turn and boom, she'd start right up. Seemed in theory like a loose wire or loose connection somewhere. I've checked all connections (I think), cleaned contacts on battery post, etc. Problem became more frequent over a matter of weeks and now it won't start at all, I just get one single "click" noise where the shift cables connect to the ignition system (pardon my ignorance, I'm mechanically inclined but have more experience with cars than my boat). -figured it was ignition switch so I replaced that yesterday, same thing, I get one "click" noise (not from starter) on some relay or switch on top of the motor. -I then pulled off the dist cap to get a look inside and the contacts were a little eroded, I cleaned the contacts off and rebolted it and no change. -I also noticed a small black wire hanging on top of the motor that looks like it should be mounted to a ground on the block or something. This is the ground for some little golfball sized component just forward of my circuit breaker switch. I put it to a couple spots that looked like it would ground but got nothing still. Note: lanyard switch is "on" and but when I turn over motor with switch in "off" position it does the same hing, one click. So it's almost as if the kill switch is in the "off" position regardless. Going to bypass this I think since I don't use it anyways. Recent maintenance before the new ignition switch yesterday: -new plugs and wires (old ignition coil wire was arcing against a bolt on the coil so I replaced all the wires.) -new solenoid last year Today I think I'm going to put in a new cap/rotor and sensor wheel, and possibly a new sensor depending on how much it is. Will also bypass kill switch to isolate that potential problem since I don't use it anyways. Any other suggestions out there? Cause If these don't fix my problem, I just hope no one is in shouting distance of my slip cause I'll definitely be cussing up something. Note: I'm kinda old school and electrical is not my strong suit. I don't have a voltmeter, I just replace things until problem is fixed. Boat is 15 years old (and less than 250 hrs) so any part under $100 that might fix it I'll just throw on for the sake of preventative maintenance. Thanks! -Smitty
 
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alldodge

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iBoaters, Gotta say I love this site! I don't post much here but this is not my first rodeo and I've tried everything within reason to fix my issue. I've got a 2000 Crownline 19' with Merc 4.3 Alpha one and thunderbolt V. I have no spark...here's the background and what i've done: -ignition switch was working off and on...sometimes I'd turn key and get nothing from the starter. I would turn key back to off and back on and turn and boom, she'd start right up. Seemed in theory like a loose wire or loose connection somewhere. I've checked all connections (I think), cleaned contacts on battery post, etc. Problem became more frequent over a matter of weeks and now it won't start at all, I just get one single "click" noise where the shift cables connect to the ignition system (pardon my ignorance, I'm mechanically inclined but have more experience with cars than my boat). -figured it was ignition switch so I replaced that yesterday, same thing, I get one "click" noise (not from starter) on some relay or switch on top of the motor. -I then pulled off the dist cap to get a look inside and the contacts were a little eroded, I cleaned the contacts off and rebolted it and no change. -I also noticed a small black wire hanging on top of the motor that looks like it should be mounted to a ground on the block or something. This is the ground for some little golfball sized component just forward of my circuit breaker switch. I put it to a couple spots that looked like it would ground but got nothing still. Note: lanyard switch is "on" and but when I turn over motor with switch in "off" position it does the same hing, one click. So it's almost as if the kill switch is in the "off" position regardless. Going to bypass this I think since I don't use it anyways. Recent maintenance before the new ignition switch yesterday: -new plugs and wires (old ignition coil wire was arcing against a bolt on the coil so I replaced all the wires.) -new solenoid last year Today I think I'm going to put in a new cap/rotor and sensor wheel, and possibly a new sensor depending on how much it is. Will also bypass kill switch to isolate that potential problem since I don't use it anyways. Any other suggestions out there? Cause If these don't fix my problem, I just hope no one is in shouting distance of my slip cause I'll definitely be cussing up something. Note: I'm kinda old school and electrical is not my strong suit. I don't have a voltmeter, I just replace things until problem is fixed. Boat is 15 years old (and less than 250 hrs) so any part under $100 that might fix it I'll just throw on for the sake of preventative maintenance. Thanks! -Smitty

:welcome: to iboats Smitty

An engine serial number would help, but I'm going to go with this is a carb engine. To find an electrical problem you need to at least have a 12V test light, and volt meter would be better. Throwing parts at a problem is one way to lighten your wallet. It sounds like your slave relay may be the issue. The two larger top post are Red/Pur and Yel/Red, bottom smaller post are Black and Tel/Red. The neutral safety switch would be in line with the smaller YelRed wire. Turn key to ON, then cross the two larger contacts on the top of the slave solenoid, the engine should crank.

Slave Relay 89-96054T.jpg
 
Joined
Aug 6, 2012
Messages
5
:welcome: to iboats Smitty An engine serial number would help, but I'm going to go with this is a carb engine. To find an electrical problem you need to at least have a 12V test light, and volt meter would be better. Throwing parts at a problem is one way to lighten your wallet. It sounds like your slave relay may be the issue. The two larger top post are Red/Pur and Yel/Red, bottom smaller post are Black and Tel/Red. The neutral safety switch would be in line with the smaller YelRed wire. Turn key to ON, then cross the two larger contacts on the top of the slave solenoid, the engine should crank.
Yes that's gotta be it! I forgot about that, Thanks for the tip. Headed there now to give it a a try. Thanks for warm welcome to the forums!
 
Joined
Aug 6, 2012
Messages
5
:welcome: to iboats Smitty An engine serial number would help, but I'm going to go with this is a carb engine. To find an electrical problem you need to at least have a 12V test light, and volt meter would be better. Throwing parts at a problem is one way to lighten your wallet. It sounds like your slave relay may be the issue. The two larger top post are Red/Pur and Yel/Red, bottom smaller post are Black and Tel/Red. The neutral safety switch would be in line with the smaller YelRed wire. Turn key to ON, then cross the two larger contacts on the top of the slave solenoid, the engine should crank.
sure enough. I crossed the two posts and it fired right up. Thanks again! there is something so satisfying about not paying100 per hour and a 300% markup in parts to the mechanic at my marina. I actually like when my boat breaks so I can learn more how to fix it. thanks again and if you're ever in Raleigh North Carolina area I've got a case of beer and a boat ride on falls Lake ready for ya!£
 
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