75 Mariner 3 cyl Still no spark.

jmburock

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Aug 25, 2005
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174
Re: 75 Mariner 3 cyl Still no spark.

It sounds like you also need to order a Mercury flywheel puller. Please don't use a gear puller/ harmonic balancer---if you bend the flywheel or break the magnets that's another $400 to throw at the motor.. You can find it on Ebay- it fits into the threads on the flywheel/ don't forget the crankcase protector cap that usually comes with it.
 

renoduckman

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Mar 31, 2006
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75
Re: 75 Mariner 3 cyl Still no spark.

Im not opposed to getting the correct flywheel puller but my flywheel dosent have any threads in it! I thought they all did? Anyway, have a wait for parts. They were not as expensive as i thought.
 

renoduckman

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Mar 31, 2006
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Re: 75 Mariner 3 cyl Still no spark.

Yes i understand now. My flywheel needs a special puller that goes into the center. Im buying one now. It doesnt have 3 holes in it like i was thinking, one big thread for a puller. Thanks
 

jmburock

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Re: 75 Mariner 3 cyl Still no spark.

Here is a picture of the flywheel puller you need, bought mine on ebay for $50. I think all the mercury flywheels (larger hp) have threads. Check ebay for good prices.
 

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renoduckman

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Re: 75 Mariner 3 cyl Still no spark.

Yes i ordered one on ebay. Looks like a good deal. Just have to wait for parts now. Thanks joe
 

jmburock

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Re: 75 Mariner 3 cyl Still no spark.

It's been one month- is your problem fixed....
 

renoduckman

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Re: 75 Mariner 3 cyl Still no spark.

HI. No. If i told you that UPS lost my part and it took 4 weeks to finally arive, you will think im making this up! Part just arrrive yesterday. Now im trying to remove the flywheel but i dont have anybody handy to help me hold it. Going to try here and i will get back to you. I guess i should have bought tool for that too. Thanks Joe
 

renoduckman

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Re: 75 Mariner 3 cyl Still no spark.

Finally had a chance to work on motor today.. Missing part arrived friday. The flywheel came off with out too much trouble. Stator and trigger also. Now for the next question. Did you have to take starter off to get the trigger wires behind starter and in the correct place? Im losing this one. I have tryed fishing and pulling it thru several times but it hangs up on those rubber insulators on the wires. Then the stator wires have to go ontop also thru small whole between starter and alum plate where switch box is. Seems like it has to come off unless im missing something. Ran short of time to day but will get to it tommorrow i hope. Thanks in advance. joe
 

renoduckman

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Mar 31, 2006
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Re: 75 Mariner 3 cyl Still no spark.

Well finally got a chance to finish. Replaced stator and trigger. Engine clearly runs better then before but still might have some issues. Wont know for sure untill i get to lake and run it. Will report back here soon.
 

jmburock

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Messages
174
Re: 75 Mariner 3 cyl Still no spark.

Hopefully you marked the position of the flywheel when you removed it so that you can put it back on in the exact same position. Otherwise timing might be advanced or retarded- one possibility for why your engine isn't 100%. Also, your gas may have aged since the last time it was run, try clean fuel.
 

renoduckman

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Re: 75 Mariner 3 cyl Still no spark.

Hi
yes i did mark the flywheel when i removed it. But the flywheel has a key so how can it not go back on the same way? I was going to take boat out today and run it but it just doenst sound good running on the ears in the yard. I must really be missing something here. Im about out of ideas and things to try. Getting tired of the whole thing! I think i have had more than one thing wrong which has made troubleshooting a problem. If you haave any more advic i appreciate it. Joe
 

jmburock

Petty Officer 2nd Class
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Aug 25, 2005
Messages
174
Re: 75 Mariner 3 cyl Still no spark.

When you say it doesn't sound good running on the muffs, what do you mean?? Is it backfiring a lot, choking, etc. Is it possible your carbs varnished as the boat sat up for the past month or so? You can try seafoaming the engine and putting in new spark plugs. What's $12 in plugs when you've spent this much so far on ignition components??
 

renoduckman

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Mar 31, 2006
Messages
75
Re: 75 Mariner 3 cyl Still no spark.

HI
It seems like the timing is off some. It runs but does not sound exactly right. It only backfires some if you shut the throttle down fast. I guess im going to have to try to set the timing. It appears to be a bit of a diffciult procedure on this motor? My service manuel says you need a dial indicator to find TDC of #1 cylinder. Then you set the timing mark with that! Then start the rest of procedure. Seems a bit more complicated that i have done on cars.
My plugs are brand new and so are the wires. They both dont have more than 1 hour on them. Im going to get some more fuel but the old gas is only about 11/2 month old. IM not sure how i can get timing off much buy changing the trigger. Maybe these motors are touchy more than a car is on this? The timing linkage looks ok and i touched nothing but just taking trigger off. Anyway, im guessing thats it. If not im about out of ideas. I do know by using my Dva that im getting good voltage to all 3 coils. And they all appear to be firing by removing them. They fire a timing light also. I have been trying to find a good spark testing tool here locally to make sure spark is strong to jump gap but i cant find one! i need one for car anyway. Now, the engine is ok at idle but as you rev up slowly it begins to not sound right. The trigger appears to be moving ok and the linkage looks good. Myabe im just off a bit on the base timing? I will try to get to it saterday and look again. Thanks joe
 
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