Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

[harrylarson]

Hello, I am getting ready to pull the flywheel on 1978, 150 hp, Johnson. I need to get a puller, so I was taking a look to see what size I might need then go to Harbor Freight or Auto Parts Store and see what I could find. As I understand I will need to mount the puller in the three holes in flywheel, so I thought I would see what size these threads might be; I tried screwing in some bolts, but either I don't have the right size or the threads in these holes are messed up. looking inside the holes they do look somewhat stripped.

Can anyone tell me what size these threads are, or have any other ideas? Do I have to use the puller? Thanks.

 

[jerryjerry05]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp




The threads are usually 1/4-20 I think???Usually they strip out the first time you try to get the flywheel off.
Use PB Blaster on the top of the shaft.
The best thing to get is a BIG 3 jaw puller.See pics.Auto Zone has then,Harbor Freight does too and a LOT cheaper.
Loosen the nut(don't remove).Install puller then tighten with impact till it's as tight as you think it will go.
Then a 2-3# hammer on the main bolt.It should pop off.Keep hands away!!!It can break bones and cut severly!!!

 

[tx1961whaler]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Actually, about the worst thing to use is a big three pronged puller. That pulls from the edges and can easily warp the flywheel. That's why the three holes are tapped in there for the proper kind of puller. A harmonic balancer puller is normally used.
The bolt size for the three that hold the puller to the wheel is 5/16-24 and should be grade 8. If they get stripped then they are easily tapped to the next size up.

 

[emdsapmgr]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Follow whaler's advice. You can probably rent a harmonic balancer puller from your local auto parts store.

 

[boobie]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

DON'T use the big three pronged puller!!!! Use the proper one for the center of the flywheel. Threads can be repaired.

 

[82Stang]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

The threads are usually 1/4-20 I think???

The best thing to get is a BIG 3 jaw puller.

On my '62 Seahorse, it was also 1/4-20 threads. You'll want grade 8 bolts. I broke some, but drilled them out.

3 Jaw puller --> NO... I tried and it wasn't pretty. Harbor Freight puller broke when cinching and I'm lucky I had safety glasses on. The harmonic balancer did the job. It took me over a week to pop it free, but the key is patience... and lot's of penetrant. Also don't use an impact. That's a good way to strip them out. Go slow and keep the puller on over night for as long as it takes. Good luck.

 

[harrylarson]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Thanks All. The threads are 5/16-24. I bought a puller from Harbor Frieght, but after the last post by 82Stang I'm taking it back and asking auto parts store for harmonic balancer puller.

One more thing any ideas on how to hold the flywheel while trying to loosen nut and when turning puller?

 

[kfa4303]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Hi harry. I used to use a large nylon strap from a ratchet set and I wrapped it around the perimeter of the flywheel so that as I tightened down on the puller, it tightened the strap. You can also use a large screwdriver and insert it between the bolts and center shaft of the puller.

 

[jere1972]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

DO NOT USE HARBOR FREIGHT Pullers they will break(very poor casting) I have gone through 3 in the past year!!!!!!!!!!!!!!!!!! those V6's are so heavily torqued down you most likely will need to worry about how to keep the flywheel from turning, while you have 2 men and a boy on a breaker bar with the puller AutoZone has a tool loaner program, like a $20 deposit then return for refund, and you must use the harmonic bal puller

 

[jere1972]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp


IF your flywheel has Holes in the top I think a 78 may have 3, you can try fabricating a bar like this one to hold the fly wheel, the nut should break free much easier then the flywheel will, I welded #8 1/4 20 bolts to for a jig, to a piece of steel angle iron from lowes, you don't have to weld them you can run nuts up if you have the thead! boobie has also made a suggestion in prior threads, to push some rope(nylon) into a cylinder the piston will top out on the rope before reaching TDC, keeping the crank from revolving!
you most likely will need a breaker bar with some muscle on the puller, socket wrench won't cut it, as mentioned earlier LEAVE THE FLYWHEEL NUT ON LOOSE, bad things will happen if ya don't!

 

[boobie]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Do the 9 amp systems have the same holes ? I think your pic shows a 35 amp.

 

[82Stang]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

DO NOT USE HARBOR FREIGHT Pullers they will break(very poor casting) I have gone through 3 in the past year!!!!!!!!!!!!!!!!!!

Proof positive. Harbor Freight is great for cheap tools. And that's what you get, cheap tools. Any of the real important tools, i.e. impact, jack, jack stands etc, I have all Craftsman. SnapOn would be better, but cost alot $$.

 

[harrylarson]

Re: Pulling Flywheel, threads maybe stripped,1978 Johnson 150 hp

Got flywheel off, awesome! I searched and read through some of the threads and it came off just as described. Harmonic Balancer Puller from auto parts store, didnt have to buy, grade 8 bolts, 5/16-24. Tightened puller down as far as I could go hit with penetrating oil for a couple days, tightened a bit more then one good shot with small sledge to top of bolt on puller and it popped right off. Oh yeah, and I had left the flywheel nut on. Thanks to all!