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npauls
06-19-2011, 11:13 PM
Well guys/gals,

I was out messing around with the little motor on my walleye rig again tonight and was going to check out the fuel filter to see if that could be part of the problem with my motor when I noticed a bunch of shards of magnet all over the motor. I have tracked the shards back to long skinny curved magnets that sit in a groove under the fly wheel. The motor is a 1999 mercury 40hp 4 stroke non big foot version.

Can anyone tell me what these magnets are for and what can happen if a couple of them shatter apart? a part number or name for those magnets is appreciated. This way I can either order them or let whatever mechanic that works on my boat know what I have found.

I am thinking that this could be the main part of the problem with my motor and want to know what needs to be done to fix it.

Thanks,

Nate

chubbdarter
06-19-2011, 11:59 PM
Well guys/gals,

I was out messing around with the little motor on my walleye rig again tonight and was going to check out the fuel filter to see if that could be part of the problem with my motor when I noticed a bunch of shards of magnet all over the motor. I have tracked the shards back to long skinny curved magnets that sit in a groove under the fly wheel. The motor is a 1999 mercury 40hp 4 stroke non big foot version.

Can anyone tell me what these magnets are for and what can happen if a couple of them shatter apart? a part number or name for those magnets is appreciated. This way I can either order them or let whatever mechanic that works on my boat know what I have found.

I am thinking that this could be the main part of the problem with my motor and want to know what needs to be done to fix it.

Thanks,

Nate

Nate im no tech...but i beleive you have a crank position sensor issue

http://en.wikipedia.org/wiki/Crankshaft_position_sensor

horsetrader
06-20-2011, 12:15 AM
As the flywheel spins the magnet charges the primary coil

you should be able to get new magnets and jb weld them in place

npauls
06-20-2011, 12:18 AM
Thanks for that link Darter,

It sure does seem like that is the problem. All the things the say are side effects of that being the problem is exactly what is going wrong with my motor. I guess I will be going to talk to Lethbridge Marine in the morning and find out what the cost of getting it fixed will be. Hopefully things won't be to pricey and can be fixed pretty quick. I would love to have my boat back on the water before the long weekend.

npauls
06-20-2011, 12:20 AM
Is there anything I have to worry about when taking the fly wheel off to replace those magnets or is it as simple at taking the nut off of the top and sliding the flywheel off of the shaft?

chubbdarter
06-20-2011, 12:22 AM
Is there anything I have to worry about when taking the fly wheel off to replace those magnets or is it as simple at taking the nut off of the top and sliding the flywheel off of the shaft?

does the flywheel have puller holes?
also im guessing it has index markings for proper replacement

npauls
06-20-2011, 12:26 AM
Ya I am pretty sure it has both things mentioned. I think I had better just get a mechanic to fix this one for me. I am far from being motor savvy and would really be ****ed at myself if I messed something else up while trying to fix the original problem.

chubbdarter
06-20-2011, 12:28 AM
Ya I am pretty sure it has both things mentioned. I think I had better just get a mechanic to fix this one for me. I am far from being motor savvy and would really be ****ed at myself if I messed something else up while trying to fix the original problem.

goodluck nate

npauls
06-20-2011, 12:36 AM
Thanks,

Appreciate the help. Makes me a bit happier that I now have an idea on what could be causing the problems. Maybe the long weekend camping trip in the boat will still be a possibility.

Braun
06-20-2011, 10:19 AM
i got a solution........ it involves a "gas spill" on the deck of your boat. drive it out to the middle of travers. (make sure to mark waypoint for next year's fishing structure.) turn off motor. fill motor case with gas. try to start motor...... swim like hell..... rehearse telling your insurance company "I dono what happened it just blew up."

npauls
06-20-2011, 11:25 AM
hahaha the boat won't burn to well bud. Almost all of it is aluminum. Even the decking under the carpet is aluminum. I am going to make a few phone calls this afternoon while the kids are napping and price out what an approximate cost will be to have it fixed.

npauls
06-20-2011, 01:36 PM
Ok I have finally figured out what those magnets are for sure.

They are epoxied to the underside of the flywheel and I guess over time can work loose. Once this happens they start rattling around and shatter when they hit something else.

I have read that you can't get replacement magnets and the whole fly wheel needs to be replaced. So now I am on the hunt to find a flywheel for my motor. I have only found one listed so far on the net and it is about $320 plus shipping.

So if anyone can give me an idea where I can find a flywheel for a 1999 mercury 40hp 4 stroke with electric start it would be greatly appreciated. In this case the less it will cost me the better.

Nate

Willowtrail
06-20-2011, 05:21 PM
Ok I have finally figured out what those magnets are for sure.

They are epoxied to the underside of the flywheel and I guess over time can work loose. Once this happens they start rattling around and shatter when they hit something else.

I have read that you can't get replacement magnets and the whole fly wheel needs to be replaced. So now I am on the hunt to find a flywheel for my motor. I have only found one listed so far on the net and it is about $320 plus shipping.

So if anyone can give me an idea where I can find a flywheel for a 1999 mercury 40hp 4 stroke with electric start it would be greatly appreciated. In this case the less it will cost me the better.

Nate

Can you not order one from your Merc dealer? I ordered a part for my Evinrude on a Monday and picked the part up Friday.

Online was $17 shipping for a $5 part. From Ecko Marine in Alberta Beach it was 10 cents more but had free shipping.

npauls
06-20-2011, 06:00 PM
All the merc. dealers are wanting the same price. $577.49.

I have found them on the net in the states for $300-$400. A couple of them had free shipping to north America so it will be quite a bit cheaper to find one on the net then order from a local shop.