got a 70ELTH yamaha with a seized bearing on the crank.
got pretty much everything disconnected but can’t figure out how to get the fly wheel off. Any suggestions from the mechanics among us?
Got a quote for about 1500-2000 to fix this thing and that’s not in the cards. Nor do I have the money for a new motor. So I figure I can’t hurt this thing any more than it already is…
Here’s to a crash course in learning!
thx for any input.
micah
use a flywheel puller. Why did the bearing fail, lack of maintinance? Better figure that out before putting it back together.
You maybe able to get it off with a block of wood, hammer and some help. Leave the fly wheel nut on by about 2 or 3 threads, put the block of wood on top of the nut while someone is pulling up on the fly wheel hammer the wood block. The reason for leaving the nut on is if it pops loose it can literally fly off pulling on it, pry bars may work too but be careful where you wedge and put pressure.
I’ve pulled alot of flywheels off crankshafts.
Loosen the nut that holds the flywheel onto the top of the crankshaft and turn it so that the top of the nut is level with the top of the crankshaft, about 5 threads or close to that.
Use a wheel puller designed for that width of flywheel or a little bigger and mount the tip of the wheel puller into the hole thats drilled into the top of the crankshaft, it should be a tapered hole.
After you’ve tightened the wheel puller to the point where your hopeing it won’t bend the flywheel, hit the top of the wheel puller sharpely with a 2 pound hammer, squarely and hard. If its going to give at that point it should come off with the help of the wheel puller.
The reason you leave the nut on when doing this is so the threads won’t flare, so you can put the nut back on, it may after several hits to the top of the wheel puller, so make sure the nut is still on the top of the crankshaft but loose enough so the flywheel pops up. Recheck for tightness after a few hits, if it loosens tighten it back up.
If there is such a certain thing as a temporary bond this is it. Right where the machineing of the taper of the crankshaft meets the taper of the flywheel it becomes a bond and sometimes you really have to crack the puller with a hammer to get that bond to break, I think this taper is called a Moress taper in machining.
If you need any help with rebuilding the powerhead via this site let me know as I’ve rebuilt several and taken apart many. The most important thing to remember when taking a boat motor apart is remember where the parts go and which way they are faceing, mark your rods caps with a punch, so they go back on right. All these parts are matched, as one part won’t fit the other rod journals, message me and I’ll help if you want.
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You maybe able to get it off with a block of wood, hammer and some help. Leave the fly wheel nut on by about 2 or 3 threads, put the block of wood on top of the nut while someone is pulling up on the fly wheel hammer the wood block. The reason for leaving the nut on is if it pops loose it can literally fly off pulling on it, pry bars may work too but be careful where you wedge and put pressure.
This is my method on most. Only difference is I use an aluminum or brass block. You want something hard to transfer shock to loosen the taper friction but you want it to be softer than the nut or crank so it wont damage it.
And remember to take a good mental note of (everything and the way its faceing). A common practice of makeing cast iron rods and machining them is to leave them whole. Then they break the cast into two pieces, the rods and the rod caps, and these breaks are never the same and won’t match the other rods on any motor, each and everyone is diffrent. Another question is does your motor have needle bearing or Babbit insert bearings, theres a big diffrence, and each needle bearing has to go back in a certain way and so do the babbit bearings. Did the rods knock befor you took the motor apart, if they did its another whole process involveing more things to do to get the engine back together right.
Can’t help ya with the crankshaft, but I’ve got an open seat for you anytime I’m available, just let me know. 
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Can’t help ya with the crankshaft, but I’ve got an open seat for you anytime I’m available, just let me know.
X 100
Sorry to hear that your motor took a dump.
Ron
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