Pulling Flywheels, a word of caution

[R.Johnson]

I see on this board many times, "pull the flywheel" These wheels are held on with a consideral amount of torque, up to 145 ft. lbs. on the large engines. These are not lawn mower engines, " loosen the nut, strike with a hammer" You can do a lot of damage to the crank, flywheel, and crank bearings without the proper tools. The wheel also has to go back on, torgue wrench, and flywheel wrench. I have friends with a garage of tools, and machines, not one with a flywheel wrench. It would be interesting to know how some of these wheels are removed. I know! harmonic balance puller. How are they but back on?

 

[rodbolt]

Re: Pulling Flywheels, a word of caution

hello<br /> some flywheels are just stuck. its always a roll of the dice. I made a puller that works a little better than most plain harmonic balancer pullers. some times I will use heat. once I actually pressed one off and it was stuck so tight part of the crank was left on the flywheel.but when you start pounding on the puller shaft always be aware that the bottom crank bearing is absorbing that blow. use a forceful quick blow to the shaft<br /> dont beat it silly<br /> good luck and keep posting

 

[OBJ]

Re: Pulling Flywheels, a word of caution

Before I start beating on it, I'll usually try the wait method...where as I get a real good tight pull on it with the harmonic and give it a good dose of JB Blaster.....then wait. It works about 90% of the time. May take overnight but you can hear it pop when it finally breaks lose.<br /><br />If it don't break lose, I give it a sharp blow or two and put more blaster on it. I dislike hammering to much. Like rodbolt said, the lower bearing is taking all the punishment. The sharp blows are most of the time enough to break it lose. Don't like applying heat neither unless it's with a heat gun. Worked a few times for me. <br /><br />No doubt a stuck flywheel can be a pain in the patut.

 

[NEECAPRS]

Re: Pulling Flywheels, a word of caution

Flywheel Removal: Would like to add to all good methods- the wait method being my favorite: Important to use pullers that the OEM intended. Often these are not harmonic balancer pullers at all.For example, the big "M" brand has a threaded hub with a jackscrew and it's the only one that will work where intended! They're expensive,but,not nearly as much as undetected damage from beating on the crankshaft.

 

[sas]

Re: Pulling Flywheels, a word of caution

Just my 2 cents worth. I am taking a small engines and marine engine course right now. Teacher (who has 20 years at OMC and 10 years at Yamaha) suggested to remove the flywheel this way. Place screwdriver under flywheel at the opposite side of keyway. With the nut still on but not tight tap shaft with hammer and apply preasure to screwdriver. Told him he was nuts should use a puller. Tried method on lawnmower it worked perfect. Tried on outboard, easy as pie. No damage, just tapped a couple of times, applied little presure and pop goes the fly wheel. Must put screwdriver on opposite side of keyway.

 

[Hooty]

Re: Pulling Flywheels, a word of caution

I don't like to whang away on the puller bolt either. If I do hit the bolt with a hammer, I use a short handle sledge, not a tack hammer. The most successful method I've found is with an impact wrench and wait. Bang away on it with the impact wrench and wait a while. If it doesn't pop off, give it another dose of impact wrench and wait. One other thing. The bolts used to attach the puller to the flywheel should be grade 8. Low grade bolts just stretch and quit pulling. Grade 8 bolts have a high tensile strenght and resist stretching. As far as puttin' it back on, I usually jam a screw driver between the ring gear and starter and torque it down.<br />Good topic R.Johnson.<br /><br />c/6<br />Hooty

 

[two2canoe]

Re: Pulling Flywheels, a word of caution

When I worked at the lawnmower shop, we used the method SAS talks about as the "quick and dirty" method to remove flywheels. I only broke the top of of 1 crankshaft. A lot cheaper to fix on a lawnmower than your outboard! When I took the flywheel off my newly acquired 1958 Johnson 35, I tried all the standard ploys discussed above. The "penetrating oil-puller-impact wrench-wait" method didn't even work and that works all the time! Finally heated the flywheel (gently) around the center and put my biggest breaker bar on the puller and just decided to pull till I broke it loose or something else broke. When it let go I must have jumped two feet! Popped so loud I thought it broke but no, it just came off. Turns out that the last "mechanic" that had it off had coated the mating surface with some sort of adhesive! Go figure!

 

[Mark42]

Re: Pulling Flywheels, a word of caution

I have removed many a stubborn flywheel from lawnmower and tractor engines by striking the crank when the puller would not do it. My experience indicates that two people should pry up on the flywheel evenly from opposite sides of the wheel. Heating around crank is a big help. Then strike the crank once with a direct sharp blow. This method prevents most or some of the impact from being passed through to thrust bearings or the (soft) aluminum block. <br /><br />This should not be your first plan of attack.<br /><br />Also, applying penetrating oil immediately after heating the flywheel will help the oil seep into the passage.

 

[AUGIDAWG]

Re: Pulling Flywheels, a word of caution

If you bang on the end of the center bolt on the puller, it sometimes works. After you hit it, tighten it again. Hit it, tighten it.<br />Is this what you guys mean by tapping the crank?

 

[Yepblaze]

Re: Pulling Flywheels, a word of caution

The OMC puller I purchased many years ago is nearly an inch thick round disc of forged steel, with a nearly one inch fine thread bolt in the middle, and not a $10 harmonic balancer puller sold at the local chinese tool store. Usually use grade five (at least) and grade eight bolts if I have them.<br /><br />The air impact gun is always handy and is used to remove and replace the nut. The actual tightening of the puller is done by hand with a BIG wrench then it usually takes a nice firm smack to the main bolt to POP it loose.

 

[8up]

Re: Pulling Flywheels, a word of caution

When I installed my flywheel back onto my 140 evinrude I screwed one of the 5/16" screws into the threaded holes around the crankshaft and placed another screw, (as big as would fit)into one of the many non threaded holes close to the perimeter. Then I simply used a pinch bar between the two screws holding pressure in the oposite direction than I was torquing. This worked very well for 140 ft. lbs.<br /><br />good luck

 

[G DANE]

Re: Pulling Flywheels, a word of caution

Good topic<br /><br />I´m here in Denmark where everything is metric. I build my own puller, by turning a disc of thick stainess steel and welding a 1 1/2 tube to it and a nut on top with 3/4 " threads in it. Just drilled holes in dish where needed. Works fine. to now i only used it on 20,25 and 35HP motors with 3 1/4" bolts. Now i have to pull flywheel from my 40 HP what is the dimension of the bolts and thread - i have to get a couple. Is it the same on my 115 V4 ?

 

[seahorse5]

Re: Pulling Flywheels, a word of caution

Larger motors use the 5/16-24 fine threaded bolts for pulling flywheels. They are also known as 5/16 NF threads. Can your local distributor order them for you? I can get the part numbers if you need them.

 

[G DANE]

Re: Pulling Flywheels, a word of caution

Thanks Seahorse - appreciate your help.<br /><br />Are the bolts available from a OMC dealer ??<br /><br />My puller disc is only 1/2" thick, but I can cut bolts if too long.