Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Blueghost924

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Hi, I have a 1982 Mercruiser 470 that is not currently installed in my boat (it's in the garage). The spark plugs and wires were old and off when I bought the engine, so I bought a new set (wires and plugs). The other problem is that the guy I bought it from had a friend who had loosen the dizzy hold down bolt and turned it (for reasons unknown), and now I don't know where the timing is.

I've installed the new spark plug wires using the Mercruiser diagram from the manual I've gotten here at I-Boats. The thing I'm wondering is that the manual diagram for wire routing shows the distributor cap top 2 plug holes lining up in parallel with the motor. Since I don't know where my timing is, I've turned the dizzy so when you are looking straight down, it's between all the left and all the way right. As such, the distributor cap wire holes don't look exactly like the manual diagram.

Looking straight down at my dizzy cap with the spark plug wires attached (and the distributor turned right in the middle), I have #1 wire at the 12 o clock position, #2 at the 9 o clock, #3 at the 3 o clock and #4 at the 6 o clock position. Does this look right for this Mercruiser 470 set up?
 
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Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Cylinder are from front to back 1,2,3,4 .Firing order is 1,3,4,2. Locate #1 piston on its compression stroke, set to 0 degrees on the timing tab,
see where rotor is pointing and call that #1, then go clockwise from there 1,3,4,2
 
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achris

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

As long as the dissy has not been removed from the engine, you shouldn't have a problem. Turn the engine until you are on the compression stroke of #1, then stop when the timing marks show 8 BTDC. Now turn the dissy CCW until the points JUST start to open. That will get you close enough to start the engine. The post (on the cap) that the rotor is pointing to will be #1 cylinder. Moving around the dissy cap CW, the next is #3, then #4, then #2...

Chris....
 
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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Wish I could add something to that but Chris and the Doctor are spot on. ;)

actually....

here's a snap shot of the timing tab marked so you know which one is 0?


and also a TSB that showed Mercruiser lowering the timing down on these due to crappy fuel.
 

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achris

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Wish I could add something to that but Chris and the Doctor are spot on. ;)

actually....

here's a snap shot of the timing tab marked so you know which one is 0?


and also a TSB that showed Mercruiser lowering the timing down on these due to crappy fuel.

The later service manual has the timing at 4 BTDC....
 

Blueghost924

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

dizzy.jpg

Here's a picture of the top view currently...as you can tell the top spark plug hole is pointing at the engine. I'm in the process of removing all the spark plugs, and am going to either bump the engine or turn it clockwise by hand using the front bolt (holding the stator cover on). I'll have to watch the marks and compare to where the dizzy rotor is.
 

Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

"am going to either bump the engine or turn it clockwise by hand using the front bolt (holding the stator cover on). "

Not unless you really want to pull the crankshaft out of the motor to take out the busted bolt. Use the slave solenoind to bump the motor over
Next option is to use the holes in the balancer and a short rod CAREFULLY so as not to crack a magnet.
 

Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

dizzy_zps7cfdede5.jpg
 

stonyloam

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

OK it does not matter which terminal points where. What matters is that the rotor points at the #1 terminal when the #1 piston is at TDC compression. The #1 terminal should be marked on the distributor cap. If the distributor had been removed at some time in the past, the cap could be oriented completly differently from the photograph, and that is OK as long as the rotor is in the correct position.
 

Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Dont think the 4 cylinder caps are marked. If the dist was never removed and just turned ,the oem pics should get him close
 

stonyloam

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Dont think the 4 cylinder caps are marked. If the dist was never removed and just turned ,the oem pics should get him close

Mine is, a little "1". Yeah he should be OK.
 

Blueghost924

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

zero position.jpg

BT Doctor - I definitely took your advice by bumping it little by little using the slave solenoid. I finally got it mark line to line up with the 0 degrees on the block, and here's where the rotor is (looking straight down). This was a little unexpected...but I'll reassemble based on this rotor position (using 1-3-4-2 clockwise). So I'll re-assemble with the #1 spark plug wire now at almost the 9 o clock position.
 

Blueghost924

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

One thing I need to mention - I recently upgraded to the Pertronix electronic ignition and Flamethrower coil (so I'm not using the points right now). I followed the install instructions exact, including making sure the gap was set using the feeler gauge.
 

Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

If your absolutely sure your on the compression stroke then use that as #1 and where the cap lines up to that, and go 1,3,4,2.
If it still dosent run or wants to backfire ,then your timed to the exaust stroke. What you do is move the wires 180 degrees clockwise.
So #1 will go to where #4 is now and you will call that position the new #1 .Then go 1,3,4,2 clockwise.
 

Bt Doctur

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

On most engines that are setup by mechanics ,when they drop a dist in the rotor will point toward #1 cylinder . This way its like a standard setting so we stand a chance of hitting it right from the start if the caps are not numbered. And it that dosent work ,then is get #1 to TDC compression and index the rotor to #1 position in the cap and drop it in .Get it running and set the timing.
 

stonyloam

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Did you bypass the resistance wire and feed a full 12v to the coil +?
 

MikDee

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Sometimes you're lucky, & there's a stake mark, or some type of mark on the Dizzy base, & block, or manifold. Then just drop it in with the crank on TDC, and Cyl #1 on compression stroke, with that mark and your rotor set to Cyl #1.
 

Blueghost924

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

Terry - it's funny you bring that up. I've read articles and posts about the purple resistor wire with the Pertronix upgrades. Currently, the (+) on my coil has the solid purple and purple/yellow wire, along with the red wire going to the Pertronix unit. I have not bypassed the solid purple wire, but in reading the research this will be necessary. I can see cutting the solid purple wire at the combined spade on the coil (+), but wasn't quite sure where to attach the new bypass wire. I believe from the articles it attaches to the purple wire at the electric choke.
 

stonyloam

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Re: Spark plug wires on correctly?? - Mercruiser 470 3.7 L

OK the way I would do it is: The purple wire goes to a connector on the electeic choke. Take the purple wire off the coil. Tape the end and coil it up out of the way (or remove it if you like). Take a stranded copper wire, and run it back to near the choke connector and make a splice (solder works best). Coat the splice with a couple of coats of liquid tape. Other end attaches to the coil +. Now when you are starting the coil gets its voltage from the purple/ yellow wire from the slave, so you will want to make a couple of voltage measurments. With the key on, the coil+ should read the same as the battery, and with the starter cranking, same thing, coil should read the same as the battery. If the voltages are right it should work.
 
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