Mercury 35hp Twin question

[billw]

I don’t know if there are timing marks on the flywheel or not; but if not, here is what I would do.

Keep in mind that most outboards I have seen like to run at around zero degrees advance in the vicinity of where the throttle plates just start to open, MORE OR LESS, for those who will choose to debate. Not BTDC or ATDC. Also, the points usually will break, right as the magnetic flux is changing direction in the coil, in other words, more or less when the magnets are dead center over the coil. You will be using these two facts to align the holes.

Make sure points are set to .020.
Bring the top cylinder to TDC.
Move the magneto to where the throttle pick up just starts to open the throttle plate in the carb
Determine which coil and point set is for number one cylinder.
#1 point set should be very close to where it would start to open. Move the mag a little, if needed, to right where the points are going to open.
Place the outer flywheel ring over the mag so the magnets are squarely over the #1 coil laminations.
Place the flex plate on and drop the center hub on so it lines up with the keyway.
Align all the disassembled parts to the closest holes sets. It should be obvious at this point.
Index everything with a marker. Take it all off and reassemble flywheel properly. Do use some red loctite.

You have one chance in six of being right, anyway. This should get you to the right bolt hole locations without any trouble…..I hope I wrote this so it make sense to you.

[davidk]

Bring it over to the Dark Lord in Waldoboro. I’m sure he’ll be glad to help.

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Attachments:

[david-bartlett]

quote Mumbles:

quote david bartlett:

so I can see where the key way is in relationship to the magnets.

I’m pretty sure I did something like that on the 200. Also look at any rust stains or corrosion to try and help match it up correctly. You can do it!

That ’65 200 I had was the Mother Of All Mercs and came straight from hell. I never did get it going and I would have gladly paid the guy who bought it just to get it out of here. All I have left are some photos.

Jim,

That is what I did. I think I have it right again. I will use info from Bill and Dave to verify.

Thanks.

[david-bartlett]

quote BillW:

I don’t know if there are timing marks on the flywheel or not; but if not, here is what I would do.

Keep in mind that most outboards I have seen like to run at around zero degrees advance in the vicinity of where the throttle plates just start to open, MORE OR LESS, for those who will choose to debate. Not BTDC or ATDC. Also, the points usually will break, right as the magnetic flux is changing direction in the coil, in other words, more or less when the magnets are dead center over the coil. You will be using these two facts to align the holes.

Make sure points are set to .020.
Bring the top cylinder to TDC.
Move the magneto to where the throttle pick up just starts to open the throttle plate in the carb
Determine which coil and point set is for number one cylinder.
#1 point set should be very close to where it would start to open. Move the mag a little, if needed, to right where the points are going to open.
Place the outer flywheel ring over the mag so the magnets are squarely over the #1 coil laminations.
Place the flex plate on and drop the center hub on so it lines up with the keyway.
Align all the disassembled parts to the closest holes sets. It should be obvious at this point.
Index everything with a marker. Take it all off and reassemble flywheel properly. Do use some red loctite.

You have one chance in six of being right, anyway. This should get you to the right bolt hole locations without any trouble…..I hope I wrote this so it make sense to you.

Bill,

Thank you! I think I matched up the rust spots and scratches to put it back together properly but your explanation will make sure I did.

Thanks again.

[david-bartlett]

quote Wedgie:

Wedgie,

Thank you. This should be what I need as long as that one wasn’t changed too.

[david-bartlett]

quote DavidK:

Bring it over to the Dark Lord in Waldoboro. I’m sure he’ll be glad to help.

David,

This is my Ace in the Hole!

[Tom]

Consider trying this…

Put the hub and key on the crank and turn the crank until points are just starting to open. Then set the flywheel so the magnets are just passing the center post of the coil with the points just starting to open. Button it all together in that orientation and see if you get spark. Then try it one bolt hole off in either direction, to verify where you get the best spark.

T

[david-bartlett]

quote Tom Manley:

Consider trying this…

Put the hub and key on the crank and turn the crank until points are just starting to open. Then set the flywheel so the magnets are just passing the center post of the coil with the points just starting to open. Button it all together in that orientation and see if you get spark. Then try it one bolt hole off in either direction, to verify where you get the best spark.

T

Good idea Tom. Thanks.

[green-thumbs]

Eight bolts so only 7 ways to get it wrong. Are all the bolt holes equidistant? One look at a
reference flywheel would get you right way. 360/8 = 45 degrees a large enough angle to
be pretty obvious the relation of key way to magnets.
You can do it by trial and error or from a reference magneto or a good clear photo.
I assume you can narrow it down from 8 possibles to 2 or 3 Cam should lift points when
magnets are passing coil…assuming points not a solid state device…may need meter
to indicate points opening and chalk mark of where magnets are.
Not my Mercury models but I have done meter thru points to dial in points on a snowblower
changing from very very reluctant to prime and pull at Zero and below. An old style magneto
not a Guaranteed to Start model.
You do not have to install more than two bolts while testing,
I have stuck my oar in the water and there may be more to this than I know so pardon
me if I am entirely wrong. Seems logical from here.
Louis

[dave-bernard]

Good thing he did not take the bolts out of the outer ring also.

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