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Magnet shards

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Bennylt

Member
1986 mercury 35.

Running rough. Seriously lacking power under load. Runs fine on muffs. Weak in the water, never got up to full RPMs in the water. Then Started surging. Revs would go up and down about every 2 seconds.

I got back after the surging incident and pulled the cowl and found a chunk of magnet. Feeling up under the flywheel I think at least one magnet is shattered.

Fist, could bad magnets be my initial running problem. Or do the rough poor running vibrate them into cracking?.

Second... I can't find used flywheel. Part 7912A12 online including eBay. Is there another one compatible?

I refuse to believe a broken magnet is going to total my engine.
 
Could have multiple issues here.

The "weak in water", surging etc could be the result of 1) carb that needs a good clean/rebuild 2) bad gasket somewhere letting in air 3) bad crank seals - upper, lower or both 4) a few other assorted issues - have to tackle them one at a time and either repair of disprove them as a cause.

Second, yes, your motor could be a paperweight because of something as simple as a flywheel that is no longer available. There are much newer models that came from Merc that are decorations for parts much smaller and of less mechanical importance then a flywheel.

ps - here is a current flea-bay listing.... http://www.ebay.com/itm/242-7912A14...ash=item5d65f79bb3:g:FQAAAOSwzJ5XbcfF&vxp=mtr
 
Thanks for the info. That sucks that I can't replace just the magnet like in omc motors.

That part you sent.... Is that the pull start version of the same one? Mine is electric start so I would also need to add the recoil parts. Probably not worth it I guess. I hope I see a useable one come available soon.

Were broken magnets a regular issue? I.e. is that why I'm not seeing any used ones?
 
Yes, that is a manual start flywheel.

I don't believe you can make it into an electric start version. Some flywheels had a (tooth ring) that screwed onto the flywheel - I believe this model had two different cast/machined wheels - so you could get it back to "functional", but without the electric start option.

The 35 was not super popular (compared to say the 25 or the 40 - both of which were prolific and also "packaged" with many boat brands) which leads to less "used parts".

You may want to try Twin City Outboards (google them, they are in Minnesota) - huge outboard recycler - may have what you are after.
 
I haven't had any luck finding a compatible one. Am I missing something? I've found a LOT of 40HP ones from the '90's and some others from the right year range but they are 4cyl.

please help.
 
Can anyone confirm here. PLEASE!!!

I need part number 242-7912A12 that is the only electric start flywheel listed for my '86 35HP engine.

I have found 242-4764A25 Flywheels available. They are not listed for my engine. however they are listed, for the 1980 2Cyl 40HP, along with the 242-7912A12 (the part for my engine) as options.

If they both fit the 2cyl 40HP (that looks nearly identical to my 35) would they both fit on my 35? Almost all of the other part numbers mfor the 40 match my 35 including all the bolts, nuts and even the stator.

I can't find the 242-7912A12 specifically anywhere. Presumably, because the 35 was a short run (only 6 years) of a not very popular engine. the 40 was much more widely sold, and has a LOT more parts available. including this flywheel.

I want to think the 35 and 40 are basically interchangeable for parts. maybe even the same block with different cylinders or something. and the fact that both parts are shown to fit the 40.... My theory is that since the 35 came after the 2Cyl 40, the older engine parts are not listed on the newer engine. however on the older engine, the newer parts are listed as replacements.

Is it worth the risk to just buy one and try it? I don't have a lot of money to throw around. but at the moment I have engine trouble, and a new engine cost A LOT more.
 
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