71 johnson 40hp flywheel problem

[kleinboy]

My 1971 johnson 40hp has suddenly started to miss terribly on one of the two cylinders. Compression check ok on both....fuel check ok. I suspect a bad point/condenser under flywheel. My problem is that I can not get that darn flywheel off. I got the main center bolt off and I am using an harmonic balancer puller with the proper three pulling bolts. No matter how tight I get the puller bolt or how much I tap on the puller bolt I can't get the flywheel to pop off. My question is can I apply heat to the center of the flywheel to get the aluminum flywheel to expand or will the heat cause to much damage inside? Any help in this matter will be greatly appreciated!!!

 

[Joe Reeves]

Re: 71 johnson 40hp flywheel problem

KleinBoy..... Do not apply heat to that flywheel as that will result in the destruction of it. Some of those 40hp flywheels are really a pain to remove but there's only one way to remove them. You say you're using the proper type puller, using bolts that screw into the three threaded holes surrounding the center of it. Tighten the center shaft of the puller as tight as possible, use a breaker bar or some other lever to apply upwards pressure under the edge of the flywheel, then hit the center puller shaft as hard as possible with a good size heavy hammer.<br /><br />Note... When re-installing the flywheel, it must be torqued to exactly 105 foot pounds.

 

[Hooty]

Re: 71 johnson 40hp flywheel problem

A 1/2" air impact wrench works like a charm.<br /><br />c/6<br /><br />Hooty

 

[seahorse5]

Re: 71 johnson 40hp flywheel problem

The factory flywheel puller works the best. An automotive puller is usually not "beefy" enough to do the job. Watch it if you hit it with a big hammer. That blow is stopped by the bottom ball bearing on the crankshaft, and that can cause the balls to "ding" the race and cause future problems.

 

[cdentii]

Re: 71 johnson 40hp flywheel problem

I just had to take off the flywheel on my 67 40hp and it to was a pain in the BLEEP, I managed to get it 1/3 off before I actually ran into problems, I had to strap down the flywheel (with my tie down LOL) to keep it from moving they do make a flywheel strap wrench however I found this to be unnecessary, then soaked with PB Blaster overnight, and then just gave it everything with a 2' cheater bar on a 1/2" drive ratchet, thought for sure something broke when it finally came. Also make sure to put the flywheel bolt on loosely to protect the threads as the puller will kick out to the side when the flywheel gives way. Hopes this helps.
Do me a favor if you could, when you get the flywheel off let me know if there is a magnet on one side and a aluminum balance on the other or if there are 2 magnets 1 opposit of each other.

 

[cdentii]

Re: 71 johnson 40hp flywheel problem

BTW I used no heat and NO HAMMERS. Yes I have plenty of both, lol