Bad Hub Magnets - 1998 Mercury Mariner 175hp 2.5 V6 EFI

[H2Okie]

if you put your plug wires on a spark box in sequence and crank the engine over you can verify the firing order real fast and the spark strength.

[Soporific]

That is a great idea. I have already indexed the flywheel and used a spark gap tester on all cylinders. Thanks

[Soporific]

So here is a screen shot of my scope with the probe on trigger wires brown and ground on the white with yellow band and two neodymium magnets on a 2" hole saw 180 degrees apart, with opposite poles out. Beautiful trigger pattern with the cordless drill on low speed spinning the hole saw with the magnets inducing a voltage into the number 1 coil on my trigger assembly. After one of the members here was sure that the original rubber magnet in the flywheel hub only was one south and one north pole 180 degrees apart, it got me thinking. The complicated magnet pattern from the factory was a push pull design as CDI site shows, however, the rubber magnet material does fail. And the push pull design was probably only necessary to boost voltage in order to trigger the switch boxes during start up because the rubber magnet material is not as strong magnetically as neodymium magnets. HOWEVER, these days, neodymium fridge magnets are not that expensive (not the ceramic ones) and available. The test I did with the drill and fridge magnets just proved my hunch, that a simple south and north pole on the hub will do if you place them in the right timing positions 180 degrees apart. Brilliant. This is a simple fix to an expensive flywheel problem. I have already removed the old rubber magnet on an old flywheel and all that remains is for me to put my two neodymium magnets onto the hub securely in the correct timing location which is very close to 90 degrees from the key spline in the hub. I will use a timing light to make the magnet location exactly where it needs to be on cylinders 1 and then 4. That is it....done.

[PanRonnie]

your solution is not very likely to work
the particular information you are looking for is on page 26
i feel your pain!

[Soporific]

Here is a picture of my super expensive test setup for the hub magnet repair.

[Soporific]

Hey PanRonnie, I hope that what I have just done will inspire the people who own these motors to dig out that rubber magnet material on the hub and put in a couple of fridge magnets, epoxy them in place after timing them with !,4 cylinders and have no more trigger issues for the rest of their motoring life. Haha.

[Soporific]

PanRonnie, thanks for the link, however I am very very familiar with that service manual...my bible for the motor.

[PanRonnie]

the black square in my previous post is a technicians guide

[Soporific]

Yep I know, I've had that one for two years now!!

[Soporific]

Once I have the motor running with my fridge magnets on the flywheel hub I will post a new Flywheel Hub magnet Repair thread with a simple method to test and then repair the flywheel hub magnet that trigger the trigger coils. Then people do not have to spend 500 bucks on a new flywheel for an old motor. Cheers.

[PanRonnie]

let me help by posting which i believe is the patent for the ignition

[Soporific]

Hi PanRonnie,

The patent is not the same ignition system although it has the essence of the bias circuit to maintain timing as rpm increases and voltages rise from the flywheel magnets moving faster and faster. It was an interesting read, but the current ignition system is different enough. The trigger and hub magnet system has been modified as has been the switch boxes since then with other patents I am sure. The hub magnet for the trigger is not a single diametrically opposed north and south pole in our current flywheels. It has been engineered in a push pull configuration.

[Soporific]

[PanRonnie]

i uploaded the wrong technicians guide
was suppose to be this one
page 50 isch

[Soporific]

The voltage flows when the trigger coil wire cuts the magnet's field. The voltage spikes when it is cutting through the highest density of the field which occurs at the ends of the magnets that are butted together in the CDI troubleshooting guide diagram. The magnet poles are the same on my flywheel however, my hub magnet is one piece of rubber not two as the CDI diagram shows. The ends of the magnets are not physical ends of my magnet. The poles switch in the body of the magnet not at the ends. Maybe some were made as in the diagram physically identical, not mine.