Flywheel holes different size than expected?? 1984 Johnson 115

[rothfm]

Hi,

I've read all the flywheel threads on this but a bit confused. Got my 1984 Powerhead on the bench and working on removing lots of crusty screws.

Initially, I had the whole motor hanging in my basement by those holes, after chasing/cleaning the holes with 5/16 x 18 thread Tap. Tap went in easily, and new grade #8 5/16x18 thread bolts threaded in fine!!--Hung the motor for over a month like that.

So, Now I'm going to use a Harmonic puller on Flywheel, but I'm concerned I'm reading that those holes on these engines are 24 thread.

I'm thinking the Prior owner may have changed the thread? Wondering if 18 thread is going to be a problem.

Should I be concerned when tightening my Puller hard? The bolts seem fine though when threaded. Guess I will find out!

 

[ob]

Re: Flywheel holes different size than expected?? 1984 Johnson 115

Once you get the puller installed and the bolts snugged up ,try rapping on the center puller shank before over tightening it and it can help reduce the chance of stripping the small holes.Then tighten it in small incriments while rapping on it between tightening.Use some liquid wrench if you have some too. Good luck.

 

[boobie]

Re: Flywheel holes different size than expected?? 1984 Johnson 115

If the 5/16X 18 thread bolts thread in fine, use them. As you said the former owner may have changed them.

 

[EddiePetty]

Re: Flywheel holes different size than expected?? 1984 Johnson 115

Please note the larger diameters for the 24 thread series. Tap Chart UNC/UNF Threads - provides tap sizes, drill sizes, pitch, (threads per inch) basic major diameter, basic effective diameter, basic minor diameter of external threads, and basic minor diameter of internal threads for UNC/UNF threads

If the original fine threaded holes have been over-tapped with coarse threads, the effective engagement area has been reduced.

Exercise caution when using the puller and proceed s previously suggested. Just sayin'.

 

[rothfm]

Re: Flywheel holes different size than expected?? 1984 Johnson 115

Thanks for the input...agreed seems 24 would have more surface holding area...So far the 18's seem aok. I will take the puller advice tomorrow when I get the nut off. Still working on the crusty bolds. Will proceed with caution.

Appreciated.

Mark