Evenrude 155

Engine keeps Cutting the flywheel key is it the timing ?
cuz it Backfires aswell ? How do i get this engine back in proper timing ?

Re: Evenrude 155

Welcome to I-boats

Get a new key, install to manufacture specs including the correct torque settings, the timing is set by the flywheel key.

Have to torque to correct specs or it will keep on shearing keys. order your key or purchase from omc/brp dealer as they are hardened keys, one from auto store may not hold up in the outboard installation.

If you do not have a manual get one, it will save you $$$ in maintenance and from throwing parts at the engine.

After the flywheel is inmstalled go to the FAQ section and read Joe Reeves timing procedures to set your timing advance properly.

Re: Evenrude 155

also make sure your timeing pointer is correct.
make sure you clean shaft and it is oil free before you torque to specs .
use only brp key or replacement,
bennyb

Re: Evenrude 155

All the key does is line up the flywheel. It doesn't hold the flywheel in place. If it's backfiring, check all the leads on each cylinder. From the timer base thru the coils to the spark plugs.

If it shears the key and then backfires, that's different. Even backfiring it should not shear the key.

Look at the bottom of the nut. If it's galled at all you'll need to surface it with a file or something similar. If it has a little burr on it, that's what you're tightening aginst. Make it flat, install a new key and it might be OK.

What holds the flywheel in place is the interference fit between the crank taper and the flywheel center hub taper. If someone has removed too much material on either (valve grind compound or polishing the crank etc) you may have lost the interference fit and the flywheel hub is sitting on the lip below the flywheel taper.

Take a look at the nut first.

Re: Evenrude 155

Also look at the flywheel magnets, make sure they have not come loose and shifted.

Re: Evenrude 155

What DHadley said . . .

Also look for burrs, chips, or galling on the crankshaft. If the crank isn't smooth, you're holding it tight against a bump in the crank. Same issue as a burr in the nut.

Re: Evenrude 155

To make sure the flywheel sits perfectly on the crank taper, you should lap the flywheel. Remove the flywheel and key. Put valve lapping compound on the flywheel hub and set it back on the crank. Rotate the flywheel back and forth by hand. This will polish the mating surfaces and insure that any dirt or residue is removed from these critical mating surfaces. When both the crank and flywheel mating surfaces appear shiny, clean very well, reinstall the key and put the crank back on. By the way, there is a pretty high torque on that flywheel. 140-145 ft lbs. Low torque can cause the key to fail.