Securing a loose screw...

[Beefer]

Not the one rattling around in my skull, but one of the two bolts/screws that mounts my fuel pump on my 1959 Johnson doesn't want to tighten, like it's stripped. The screw looks fine, so it must be the female side that is stripped. How can I secure the screw? When I took the screw out to replace the diaphragm, I noticed 'string' in the threads. I was thinking of wrapping it once with some rescue tape. Anyone have better ideas?

 

[kfa4303]

Re: Securing a loose screw...

HI Beffer. You can try re-tapping the threads to clean them up a bit, but if they're really stripped you may have to either get a new bypass plate and/or install a helicoil (if they make the that small). Either way, I would remove the bypass cover from the block before you do any machining, or repairs so you don't get any metal shavings into the cylinder or engine internals. Buying a new cover my prove to be the cheapest/easiest solution in the end, but let us know what you come up with.

 

[MH Hawker]

Re: Securing a loose screw...

helicoil insert or if I remember right lock tight has a form a tread compound stuff not sure how it works on alum though

 

[cyclops2]

Re: Securing a loose screw...

Buy a plate if you can. The other hole has probably been overtightned & started stretching those threads by now.
No plate available ? Take it to a good marina for repairs.

 

[JB]

Re: Securing a loose screw...

Do it right.

Take the bypass cover off. Drill the offending hole out to 1/4" and tap it for 1/4"x20.(I am assuming that the original screw is a #10 or smaller) Then use a 1/4"x20 ss nylock screw to mount your fuel pump.

I have used this method to repair several alloy castings with stripped screw holes, and even one iron casting. Never had a repeat failure.

 

[Tim Frank]

Re: Securing a loose screw...

Do it right.

Take the bypass cover off. Drill the offending hole out to 1/4" and tap it for 1/4"x20.(I am assuming that the original screw is a #10 or smaller) Then use a 1/4"x20 ss nylock screw to mount your fuel pump.

I have used this method to repair several alloy castings with stripped screw holes, and even one iron casting. Never had a repeat failure.

If you drill out to 1/4"....your 1/4-20 tap will not do anything....
To tap a hole 1/4-20 you need to use a #7 tap drill (in a pinch a 13/64" drill will do)

 

[JB]

Re: Securing a loose screw...

If you drill out to 1/4"....your 1/4-20 tap will not do anything....
To tap a hole 1/4-20 you need to use a #7 tap drill (in a pinch a 13/64" drill will do)

Absolutely correct, Tim. My bad.

 

[Tim Frank]

Re: Securing a loose screw...

Absolutely correct, Tim. My bad.

Easy mistake to make...both in print ...AND in the shop...BTDT, GTTS :facepalm:

 

[kfa4303]

Re: Securing a loose screw...

Either way, I think we'd all like to see how you fix it. I agree that buying a whole, new plate is probably easier, but I'm all about the DIY and homebrew solutions. Good luck. Keep us posted.

 

[boobie]

Re: Securing a loose screw...

I guess I've been around to long 'cause I've got the heli-coil sets in my tool box to service the smaller threads. Have never used anything but heli-coils to repair stripped threads on outboards. If you haven't got them a good marina or machine shop could also do the job.

 

[F_R]

Re: Securing a loose screw...

Heli coil is the way to go, if you can't find a replacement cover. But if the OP doesn't already have a kit, he would be better off ($$) getting somebody to do the job.

 

[Beefer]

Re: Securing a loose screw...

For those who care...

So I can't find a replacement bracket/cover/plate (whatever you want to call it). The motor was converted to a fuel pump, and the only bracket/cover I can find is the original, which doesn't allow for mounting the fuel pump.

After much consideration, I'm going to retap the holes to a 12, and be done with it.