65' Merc 900 Ignition issue

65' Merc 900 Ignition issue 10 years 2 weeks ago #108568

Explorer_61
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I just purchased a 1965 Merc 900 with Merc Control. When hooked up to the battery the choke solenoid will work from the control but when I turn the key there is nothing. Any ideas? Side note, I got a great deal on the boat, motor and trailer because the motor wouldn't start, even when the previous owner tried to jump it. It would turn over but wouldn't start. He flooded it and I offered him $300 for the whole rig. 1965 Crestliner Flying Crest, 65' Balko Trailer and the Merc 900 with complete Ride Guide Indicator Steering. Even has a 18 gallon steel long cruise tank. But back to the starting issue. Any ideas. Thanks.

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108569

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108570

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108571

ed-mc
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Take a look at the attached wiring diagram. You'll need to see if you're getting power to the starter solenoid when you turn the ign switch to "Start", and work your way back from there.

Note that the control box contains a Neutral Safety Switch and if that is busted or malfunctioning, can be a cause of "no start".

HTH.........ed

File Attachment:

File Name: Merc_700_8...Diag.pdf
File Size:60 KB

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108579

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I'm not sure I am interpreting your description correctly?
If you are saying that when you turn the ignition key to "ON" and push the choke button it works, but when you turn the key on over to 'START' you no longer have a response from the choke,...It sounds to me like a resistance issue in the battery cables & related connections.
And,...You need to hold the choke button down as you turn the key on over to 'START'. If - when doing this, the choke releases - you have a resistance issue in the wiring.
If I'm not understanding your issue correctly - please explain it a bit different for me.
doc

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108580

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Thanks for the tips. I'll tinker with it this weekend and give an update on Sunday. Doc you are correct. I'll check the wiring for resistance issues. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108641

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	All of the insulation on the wires was shot. When I took the key switch out it all broke apart. I will try to rewire it first before I order a new key switch, choke & safety switch. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108642

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Photo of the offending wires. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108643

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108644

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Ok, third try to attach image. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108645

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Attachments: Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108646

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108648

ed-mc Away Platinum Boarder Posts: 1422 Karma: 232 Thank you received: 121	Looks pretty hammered! Might be the source of the problem! I would cut the cable back to expose good, solid wiring, then resolder all the leads to the ign switch, etc. Looking at all the bare wiring, it's a miracle it didn't short out and burn up! Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108651

Dr_Frankenmerc Offline Contributing Member Posts: 1433 Karma: 185 Thank you received: 44	And,...Carefully study the wiring diagram Ed linked to, because a black wire in one place can reference (-) ground, where another black wire is (+) 12vdc. Crazy - crazy - crazy so be careful. doc Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108652

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	you might not find good wire when you strip it back. will look good but the insulation will crack. I have had NOS wiring do just that. Sorry hope I am wrong with yours. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108653

NJTriton Offline Contributing Member Posts: 289 Karma: 12 Thank you received: 0	Mine did the same thing when I rewired. Turns out the lever wasn't exactly in the neutral position so the safety switch kicked in. Looks like you need to retire anyway, it's not hard, just time consuming. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108661

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hope you find some good wire in the harness but,,might be better off looking for a new harness . they all seem to dry up over time and fall apart... i have a 79 115 that every wire on the engine fell apart like that.. ended up just replacing everything..at least this way i'll know its good and not have to worry about it again...

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108666

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	new harnesses are still made after market they are worth it. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108680

vintagerunner Offline Expert Boarder Posts: 267 Karma: 18 Thank you received: 1	just the peace of mind in not having any electrical issues out on the water make a new harness it worth it.. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108681

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Been looking online, can't find a replacement harness for a Pre-66 Merc. only 66 and up. CDI and others don't go back that far. Am I missing something? Which external harness manufacturer should I be looking at? Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108685

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	try CDI. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108686

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	CDI only has external harnesses going back to 1968. My Merc is a 65' Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108696

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	get an external and a internal and wire it to fit your motor. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108760

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	What year internal & External would you recommend? Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108770

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	6cyl late 60's early 70's. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108795

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The CDI harness does not have the 4 screw square collar to mount to the cowling. Its does not have that square collar and is made for the newer motors without the 4 screws accessable from the outside.

I have not done this before, but I think it would be fairly easy to make an adaptor plate to hold the newer style harness in the old style motors. Worth looking into.

Conrad

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108811

dave bernard Offline Platinum Boarder Posts: 1471 Karma: 95 Thank you received: 30	Yes I did just that on a 4cyl. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108816

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I cut back the outside sheath on external harness last night and all the wires were ok but as soon as started to bend them the orange wire insulation crumbled away. I kept cutting back and it kept crumbling. Bummer.

Just a thought anyone have any experience refurbishing their own harness and use the old plug or does everyone just spend the big $$$ and buy one from CDI?

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Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108819

MarkS
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I've rewired two, a 700FGS and a 1000. Just took the wiring diagram, went one wire at a time, and replaced the harness back to the plug. One I was able to salvage the original plug (cobra head?), the other I bought a NOS plug end from Ferguson Poole Marine, worked out just fine. I would definitely used marine grade wire and terminal ends, or you may be doing it over again in the future..... Just my two cents.

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Mark

Re:65' Merc 900 Ignition issue 10 years 2 weeks ago #108830

Explorer_61 Topic Author Offline Fresh Boarder Posts: 35 Karma: 2 Thank you received: 0	Want to confirm it is 14 gauge wire before I spent $80 on it. Any input? Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 1 week ago #108865

MarkS Offline Moderator Posts: 5348 Karma: 118 Thank you received: 5	If memory serves me correctly, the majority were 14ga., with the exception of the main power wire (red) that was 12ga. Been a while back, maybe one of the experts can confirm or advise? Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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Re:65' Merc 900 Ignition issue 10 years 1 week ago #108870

ed-mc
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The ebay item id given is invalid, no result has been sentJust a quick question, is the copper intact and shiny, not green, corroded, crumbling?

If it's just an issue of the insulation, all you need to do is open up the cable and go back as far as needed, and cover each wire with heat shring tubing. Then tape-up the harness. I picked up a 100' roll of small heat-shrink on eBay for a pretty good deal. Much less than buying all new wire and splicing it in.

I used 1/8" shrink for a stereo job; your wires are a bit larger and will need something like 3/16" or 1/4". Best thing to do is ask the vendor how far down the tubing shrinks.

Here's an eBay search for the stuff I used; the xScorpion brand shrink was excellent quality and did a nice job on my wires:

HTH.........ed

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Re:65' Merc 900 Ignition issue 10 years 1 week ago #108944

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ED Ive dont eh same thing before. I cut it back to the plug. Then pull the wire thru the shrink tube.

I use baling wire straightened out and feed it thru the shrink tube. Then hook it to the old wires and pull it back thu, then hit it with a torch to shrink it all up.

Works pretty good when the wires are still good but the insulation is crap. But Ive had some harnesses where the wires are so bad I just find a better harness.

Working with a new harness is like the biggest christmas present to yourself tho.....
C

Conrad.

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Re:65' Merc 900 Ignition issue 9 years 10 months ago #110998

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Update! After spending some time on other projects I devoted my attention to the Mercontrol with the bad wiring.

I ordered a new neutral safety, choke and ignition along with the proper colored wires for the external wiring harness.

When the parts arrived the ignition was wrong, it had to many tabs on the back so back it went and I figured I would try reusing the old one and see if it would turn over. Never having done any electrical work on Merc's before I was a little hesitant but figured what the heck.

After a complete cleaning of the inside I rewired and replaced the internal electrical components for the Mercontrol and cut back the wires in the harness. I got to within 9 inches of plug before I got to wirres that weren't rotten and corroded. The Orange "Battery" wire was the worst and all the wires hat water intrusion and were corroded.

Got everything wired and put back together, "no small feat as I had never seen the inside of Mercontrol before 2 months ago.

The motor fired right up and my rebuilt external harness did the trick. Just need to rplace the bad battery terminal wires and it should be ready to hit the water.

Thanks for the help and insight. Makes owning these old beauties easier.

Thank you, thank you, thank you.

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Re:65' Merc 900 Ignition issue 9 years 10 months ago #111012

ed-mc Away Platinum Boarder Posts: 1422 Karma: 232 Thank you received: 121	Excellent repair job; congrats, you can go get your "Classic Merc Mechanic" qual card signed at last!! Cheers..........ed Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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TOPIC: 65' Merc 900 Ignition issue