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Flywheel Key Breaking

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scruffy63

Regular Contributor
I have a 1973 Johnson 25hp Recoil start that is constantly breaking the flywheel key. I can't find anything wrong. Flywheel is tightened correctly and key is correct. Any help?
 
Are you using a key from the BRP dealer or a hardware store key; all gurus say use only the BRP key abd make sure your shaft is clean and dry as well the hole in the flywheel. You are using a torque wrench of known good quality?
 
Torque is correct and used the last of OMC keys. Next will have to be hardware store key. This happens after running several times in barrel.
 
IF--If it truly is torqued to 40-45 foot pounds, and the tapers are clean and dry, and you are using the correct key, then the tapers and/or keyways are damaged. Flywheel taper could also be spread from over torquing by someone in the past.
 
Simple ----Use valve grinding compound to lap the tapers together-----The key merely positions the flywheel.--------Properly matched tapers will lock when the nut is torked and that drives the flywheel.---The key does not drive the flywheel !!----Make sure you use a factory key and not an off the shelf item !
 
CS-FW_Key_Align.jpg

Aligned "Vertical" with crankshaft and driveshaft... NOT aligned with the crankshaft "Taper"!

NOTE: DO NOT use a hardware store woodruff key as per your plans UNLESS you desire additional problems! You are overlooking something and causing your key breaking problem already as it is.

Are you by any chance confusing "Inch Pound" torque against "Foot Pound" torque? The flywheel nut torque must be calculated in "Foot Pounds!".
 
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I am fixing my motor. Joking said I would put it in my book of tips because when I learn something I did not know its valuable to me. Sorry you took it wrong.
 
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