help with flywheel bolts

[rsimmons42]

I have a 1977 70hp johnson model 70EL77S. I cannot seem to find out what size I need the three bolts to be on the top of the flywheel. I know they need to be Grade 8. Will someone please tell me the size?

Thanks

 

[alangf]

Re: help with flywheel bolts

They should be 1/4-20. The length probably should be 3 to 3 1/2 inches. It is not necessary for the bolts to be tight in the flywheel. Use care not to run the bolts into the flywheel so far that they hit and destroy the coils if the coils are under the flywheel.

 

[rsimmons42]

Re: help with flywheel bolts

The 1/4-20, are too small. Any other ideas?

 

[James R]

Re: help with flywheel bolts

5/16 24 should do it.

 

[bob johnson]

Re: help with flywheel bolts

5/16th -24 is what my 1988 70 rude uses..

i just cleaned them out with a tap, because i am getting ready to pull the flywheel.

BOB

 

[Rick.]

Re: help with flywheel bolts

At the top of this forum there is a thread "top Secret Stuff". There is a bit about removing your fly wheel in there on the link about replacing coils. Rick.

 

[alangf]

Re: help with flywheel bolts

The 1/4-20, are too small. Any other ideas?

Sorry about that-- honest mistake. I'm glad there was someone to give you the right info and set me straight.

 

[bankerjohn]

Re: help with flywheel bolts

Sorry about that-- honest mistake. I'm glad there was someone to give you the right info and set me straight.

Don't feel too bad ... the Johnson/Evinrude factory manual for my 1996 9.9 4-stroke motor clearly reads "Use a flywheel holding tool as shown on page 3-6 and three P/N 307641 screws from OMC Universal Puller Set, P/N 378103, or other suitable tool to hold the flywheel."

Part number 307641 is a 1/4"-20 x 2 1/8" bolt ... which is the WRONG SIZE! The correct size bolt is 5/16"-24 (SAE fine thread).

 

[daselbee]

Re: help with flywheel bolts

Yes...and to show how consistent Evinrude is...
my 1996 200 looper and 1998 225 looper both use 5/16"-24 threads in the flywheel. So , from 9.9 to 70 to 200 to 225...they all seem to use the same threads. I like that consistency.
I do chase them with a tap to clean paint and rust out before hand threading them in.

 

[tashasdaddy]

Re: help with flywheel bolts

it would not hurt. the older small ones use 1/4 20 then the bigger they got they increased in size.