No spark on a Mercuiser MCM 260 GM 350

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AL350SEARAY

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Thank you for taking the time to view my post. When dewinterizing my Searay it started right up after pumping the throttle a few times. Ran it on the hose for a little while and turned it off and restarted it several times. First time out at the lake it started perfectly. I put it in the water and pulled up to the dock. I went to grab my cooler and when i came back it was off. It would not restart and does not have spark at ignition coil main lead. It has a conversion to a electronic ignition system with an ignitor. Battery shows 13.2v and i am getting 12.4V at both the + and - sides of coil.
I disconnected all wires to coil except the 12v+ power source and the wires coming from the ignitor. I have installed a new ignitor kit with a new rotor and cap. When cranking the voltage drops to 10.5V at the igniton coil. I tested resistance between + and - posts on ignition coil and it is 1.4 ohms. Also tried it with another ignition coil which shows 2.4 ohms. It ran perfectly at first, which i knew was to good to be true. I don't understand what could have caused it to die. I have read several posts in the last few days and have tried the things they recommended. If anyone has any suggestions on my next move i would appreciate the help. Thank you.
 
Don S

Don S

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Re: No spark on a Mercuiser MCM 260 GM 350

What year? What ignition system? Serial numbers work wonders.
 
Don S

Don S

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Re: No spark on a Mercuiser MCM 260 GM 350

achris said:
You had this problem a year ago....

http://forums.iboats.com/mercruiser...version-kit-installed-546473.html#post3749540

Don, It's a 1978 converted from points to electronic. He wouldn't give us any more than that a year ago, I can't see him being any more forthcoming this year...

Chris........
Click to expand...

Sorry, we shouldn't have to go back through all the posters old thread to find out what he has. He needs to tell us what he has :facepalm:
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

I am sorry for the lack of information. It is a 75 Searay with a Mercruiser MCM 260 engine serial number 5375179. The electronic conversion kit in the distributor is part number 18-5296. If anything else is needed please let me know. Thank you.
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

achris you are correct. I posted this same issue last year. i followed all the suggestions posted and it ended up being a faulty distributor cap. i posted my finding and am hopeing for similar results this year. thank you.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

OK.. That serial number is 1979, not '78 or '75. (That's why the serial number of the engine is important, not the year of the boat)... The ignition kit consists of just a sensor in the distributor with 2 wires (I suspect) out to the coil. IF you're using the right coil as recommended by the kit maker, then there's really only a few possibilities.

1. 12 volt supply to the system. (you have already verified)
2. Faulty sensor in the distributor.
3. faulty coil.
4. tacho (or the wire associated with it) grounded.
5. closed interrupt switch.

Disconnect the tacho and interrupt switch wires from the negative terminal on the coil and see if you get spark. If you do... If you don't, throw in your spare coil... etc...

Chris..........
EDIT: at this price, just get a new one and keep it as a spare...

http://www.iboats.com/mall/partfind...gd_poid=242881&gd_row=25&session_id=566562525
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

Don S said:
Sorry, we shouldn't have to go back through all the posters old thread to find out what he has. He needs to tell us what he has :facepalm:
Click to expand...

Completely agree. I noticed he only has 12 posts, so figured it wouldn't be too difficult... Read through most of them (do I have too much time on my hands or what!!!) and there is so much conflicting information, it's just mind-boggling....

Anyway, it was just a curiosity thing... Promise it won't happen again sir... ;)
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

I thank you for your time. I have left only the two wires from the new ignitor (sensor) in the distributor and a 12v+ wire, with key on, connected to the coil. I have tried the coil i ran all last year after i replaced it when troubleshooting last years issues. Ohms from post to post test at 1.3. I have also tried the coil it had on before, which i kept since it ended up being the distributor cap. Ohms on it test at 2.4. If that is the only thing it could be i will order another one. Again thank you for you time. I have put alot of sweat into this old boat and am thankful for any help to get me and my family back in the water.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

If you only have the sensor (ignitor) and the coil hooked up, and you've tried another coil... That only leaves one thing... The sensor (ignitor)...

Good luck...
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

Thank you for the link. It is the same kit which i installed this morning. (reference post #5) I am at a loss. Is it normal for voltage at coil to drop to 10.4V while cranking motor. Thanks.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

AL350SEARAY said:
.... Is it normal for voltage at coil to drop to 10.4V while cranking motor. Thanks.
Click to expand...

Yes.

Did you replace the reluctor wheel at the same time? Also check that the distributor plate has a good ground connection.
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

Reluctor wheel? I'm sorry i don't know what that refers to. I installed the kit plus a new cap and wire coming from coil to cap. I ordered a new set of wires but recieved wrong ones. I also checked the plugs and the order in which they are hooked up to cap. I will go outside and check ground on sensor baseplate immediatly. Thank you.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

Reluctor wheel. It's that black thing that goes over the distributor shaft. That's what the sensor 'reads' to know when to fire....
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

If it is the piece that goes over the shaft between the plate and the rotor then yes. It is part of the kit. I have checked to make sure the sensor baseplate is grounded and it is. Thank you for your patience and continued help.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

Take the cap off and crank the engine, just make sure the distributor shaft is turning....
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

Yes sir. Just checked and shaft is turning. Also, probably doesn't matter, checked to make sure rotor was not grounded.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

You are checking that you have spark coming from the coil, yes? Not waiting for it to pass though the rotor and dissy cap...
 
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AL350SEARAY

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Re: No spark on a Mercuiser MCM 260 GM 350

Yes sir. I am checking for spark from the lead coming out of the center of the coil. I am thankful for your continued help and sorry for the delayed response.
 
achris

achris

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Re: No spark on a Mercuiser MCM 260 GM 350

To summarize.

You have only the power lead going to the + terminal of the coil, the 2 wires from the ignitor going to the coil, red to +, black to -. Nothing else hooked to the coil. You've checked that the distributor shaft is turning, swapped the coil and the ignitor (and it's reluctor), check the ignitor plate is grounded (checked direct to the battery?). That may lead to another conclusion. You have a dead coil AND ignitor... Have you tried swapping both out?

Chris.......
 
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