Timing -- oops I think

USAFitz

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Apr 27, 2007
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'71 Mercury 650 sn:3075151

I've read all the threads I could find on timing, including the FAQ, yet I still have a plethora of questions. First of all, I think I may have screwed up. I am replacing the timing belt so I took off the fly wheel and distributor pulley cap. Now neither are in the same position they were in before I took them off. Call it a lesson learned. So now, the manual and the literature on this forum don't all go together. Here's my questions:

1. Can I just remove the #1 spark plug, find TDC, and then re-align the flywheel timing marking on the TDC tick marked on the cowl?

2. Where should I put the distributor pulley? The manual talks about an arrow on the pulley which I found. I'm guessing I can use that (per the book) after I figure out question 1.

3. I don't have a tachometer, so can I time it by sound using the steps in the FAQ?

finally, I have an off the wall question. My trigger that the distributor cap connects to has some bad looking wires (3 connecting to the switchbox). Is it possible to rebuild this trigger and possibly replace the wires?

Thanks for the help, as always!
 

Laddies

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Re: Timing -- oops I think

Yes with a screwdriner find TDC and then align the timing marks on the flywheel then with the plate off the dist pulley align the arrow with the TDC mark on the flywheel and centerline of the crank
 

USAFitz

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Re: Timing -- oops I think

Awesome, thats what I did and it seemed to work. Idle is extremely high, so my next step is to tune it according to how Clam said to.
http://forums.iboats.com/showthread.php?t=128495

If anyone has some time, I have a couple of questions about that as well. Can I do the timing in my driveway with a hose or do I need to have it in the lake like he suggests? Also, why do you take out all of the spark plugs except for #1? how does that make a difference? Thanks.
 

hkeiner

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Re: Timing -- oops I think

Can I do the timing in my driveway with a hose or do I need to have it in the lake like he suggests?

The motor should be in the water because the back pressure from the water affects idle speed.

(Edit: My above comments were unclear. They were intended to apply to when you set the IDLE TIMING. Idle timing is set by adjusting the idle speed to the specified RPM using a tachometer with the motor running in the water. As explained later in this thread, WOT TIMING is set using a timing light, with the plugs out and the motor cranked briefly with the starter. No water is needed when cranking the motor with the starter. Sorry for any confusion.)


Also, why do you take out all of the spark plugs except for #1? how does that make a difference?

The other spark plugs are removed so that the starter can spin the motor faster.
 

USAFitz

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Re: Timing -- oops I think

So does it suffice to say that it would idle faster in the carport because of the lack of back pressure?

also, does anyone know if you can rebuild an ignition trigger -- reference first post -- (type III thunderbolt)?
 

timmathis

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Re: Timing -- oops I think

You set the timing at cranking speed with the plugs out.
Not when motor is running.
Check it while it is started to make sure it is set right at max advance.
You can replace the trigger wires up to a point. The trigger part is a molded sealed unit made inside the distributor body. So you can carefuly replace up to that point. If the wires are bare you must replace the trigger or repair what you have. Tim
 

Clams Canino

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Re: Timing -- oops I think

>> Check it while it is started to make sure it is set right at max advance.

And you can only check it started IN the water - in gear. Runit up to max advance in neutral and you could kill it. NEVER exceed 2000 rpm in neutral, for any reason - ever.

Also... when the belt is on right... the little nib on the bottom of the dist. pulley will line up with the little nib on the crankcase - when the #1 piston is at TDC. Easy to check - that's how the factory assembled them to begin with.

-W
 

USAFitz

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Re: Timing -- oops I think

Awesome... I hate to admit it, but I probably would have tried to start the engine with three plugs out, I'm glad I asked! Thanks again for taking the time to answer.
 
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