Re: The 2010 FrankenMerc Project
Started the weekend a little early so went and got the stainless hardware I needed and a few other necessites.
The first thing I did was fill the lower unit with lube so I wouldn't forget to do it later. I fill it until it runs clear and then let it settle for an hour or so. Then I top it off. I put the upper plug in then remove my pump from the lower and let a couple of ounce of fluid run out then put my plug in. That leaves a little room for expansion and keep it from blowing seals.
Next I started mounting carbs and running tubing. I alway start with the bottom carb when installing. Just a little trick I learned.
I'm running a 2.5 intake so I'm using the WMV style gaskets. I cross drilled the choke wells in the carbs so they dump into the venturies instead of dumping into the intake channels that don't exist on these intakes.
You'll want to run as much of the choke tubing as you can as you install the carbs. You can do it later but it's eaiser to route it now.
Here's all the carbs mounted -
I then installed the trigger and the stator. The trigger has 3 coils in it and the magnets for the trigger are in the center hub of the flywheel. The trigger is completely independent of the stator. The center hub of the flywheel actually has two sets of magnets. These are layered top to bottom and are reversed. In the first 180 degrees of rotation the three coils generate around 2 volts and then because of the second set of magnets, the coils produce voltage again in the second 180 degrees. This is how they get away with only using 3 trigger coils.
Trigger coil # 1 fires #1 switchbox SCR during the first 180 degrees and then fires # 4 switchbox SCR on the second 180. Coil #2 fires 2 and 5 and Coil # 3 fires 3 and 6. Rember we're talking about trigger coils not spark plug coils.
As you can see if you don't have fire on 1,2,3 it's pretty hard to blame the trigger. but if you had no fire on 2 and 5 then trigger coil #2 would probably be the culprit. O.K. that's how the trigger works so now let's mount it up.
I polish the surface where the trigger sits and I put a light coat of 2-4-C on the surface for lubrication. I then set the trigger in and check for binding.
Now let's take a look at that stator and dispell a few myths. This is a CDI stator which has exposed coils. This is also a 16 amp stator. I have a 40 also but I'm breaking the motor in with the lighter 16amp flywheel so I use the 16 amp.
This post was edited on 07/4/2010 ==
Here's a close up of the coil.. The charging coils and the spark coils have one thing in common... Negative. There is no ground in these circuits but it is common to refer to negative as ground just as we refer to it as ground when it's real name is earth, just ask someone from the UK.
You'll never have a connection to earth in a boat unless you are clearly stuck in the mud.
The negative side is provided by the battery or the stator/alternator if the battery is not present. Because the stator is an alternator the act of passing a flywheel magnet over a stator coil will produce both negative and positive voltages. It is for this reason that you are always cautioned to remove the plug wires to prevent accidental starting when working on the engine.
If a charging coil or a spark coil should short to negative or if a rectifer/regulator was shorted to negative (or for that matter anything with a positive voltage) it would probably at the very least, cause erratic spark. The most common and least obvious visually would be the rectifier/regulator which is why one of the procedures in trouble shooting is to disconnect the two yellow wires (stator charging circuit) from the rectifier/regulator.
The pulses for your tach are determined by the number of magnets in the flywheel. If you have 6 magnets you will have 6 pulses because a magnet would pass over a coil 6 times every revolution of the engine. In reality, you would have 12 pulses as the voltage alternates between positive and negative. Approximately 1/4 of the way through the pass the voltage will be at peak positive (lets just say it's +12v) and at 3/4 of the pass it will be at peak negative ( lets just say it's then -12v). This point at which the phase shift occurs is not exactly at 1/2 but this info is accurate enough for this example and for what you need to know to make your engine run correctly.
Stator position is first determined by where the wires come down the block. This is the normal position--
Now align the screws in the screw hole adjusting positon as necessary. If you experience a weak spark condition, then go back and move the stator one screw hole in either direction to correct it. You'll do this as part of the pre start link and synch procedure.
The reason this occurs is becuase of the way the magnets pass over the coils and the fact that the trigger is independent of the stator.
If a stator magnet is passing over a coil too late or too early and the trigger magnets (center of the hub) pass over their coil on time then the trigger voltage will flip the electronic switch (SCR) in the switchbox. This will release the voltage in the switch box capacitor to the coils before it has reached it's full potential voltage. If the voltage is high enough it may still produced enough voltage to jump the gap at the plug but the spark will be weak and could be intermittent. In a worst case scenario, there will be no spark at all.
As a side note, a misaligned stator could still start and run an engine with fairly good results if other compensations were made, (and they usually are). As time goes on the problem will likely begin to show up as a rough idle and poor performance (lower than normal max RPM).
The above is the reason we stress the use of a DVA when reading voltages from the stator. The test for a misaligned stator is first the spark tester, then the voltage at the positive side of the coil. Finally we need to test the stator to see if it is producing the correct voltage. If the stator is misalinged or out of synch with the trigger it should still produce the voltages it is supposed to. If the stator is producing the correct voltage, turn it 1 screw hole in either direction and retest at the coil. If the voltage is niow lower or non existent at the coil then the problem is not the stator it is the switch box. Put the stator back to the original position, replace the switch box and test again. If the voltage at the coil is now correct, then button it up and go boating.
Continued in next post...
. I was just trying to say that there are a lot of different way's to skin a cat so if you find a better way.. By all means go for it.
