Remedy for galled transom clamp screws

[pblarus]

I have a 1980 25 hp Johnson which was in the weather so long that the transom clamp screws seized to the transom bracket. They would not budge and I had to hack them off to remove the engine from the transom and then drill out the clamp screws. What threads remain are in bad shape.

The dealer tells me I can order new screw clamps but that they are going to seize again anyway.

I can't be the only person that's had this problem ... has anyone come up with a good solution to this one?

I am thinking HeliCoil and then new transom screws ... or just large stainless steel bolts and religious/liberal application of Never-Seez.

Many thanks!

Preston

 

[tashasdaddy]

Re: Remedy for galled transom clamp screws

does this motor have the holes on the transom bracket to thru bolt it to the transom.

 

[pblarus]

Re: Remedy for galled transom clamp screws

It does. The holes are 5/16, which I guess would be robust enough ... still, I'd like to retain the clamp capability.

 

[F_R]

Re: Remedy for galled transom clamp screws

An age-old problem. I see you are in SW fl. That explains it. Only way you're going to prevent that is to back the screws off and re-lube them whenever you lubricate the rest of the motor. I prefer Anti-Corrosion Lube rather than anti-sieze. And don't use Stainless Steel...they will corrode in even worse, and when they do they are extremely difficult to drill out.

 

[pblarus]

Re: Remedy for galled transom clamp screws

Does anyone know if the thread diameter and pitch is standard? If it is, I could install Heli-Coils to restore the threads and then buy replacement screws.

Anybody suggest a place to buy the replacement screws?

 

[Lakester]

Re: Remedy for galled transom clamp screws

Does anyone know if the thread diameter and pitch is standard? If it is, I could install Heli-Coils to restore the threads and then buy replacement screws.

Anybody suggest a place to buy the replacement screws?

hello,

if this was my project, i may consider talking to a machine shop. they may be able to shed some light on just what feasibly can or cannot be done...

good luck~

regards

lakester

 

[F_R]

Re: Remedy for galled transom clamp screws

Does anyone know if the thread diameter and pitch is standard? If it is, I could install Heli-Coils to restore the threads and then buy replacement screws.

Anybody suggest a place to buy the replacement screws?

On my '84 they are 5/8-11. That's been a standard size for years. Any Johnson/Evinrude dealer should have or get them. Or you can order them direct from "http://shop.evinrude.com/" without the (") marks

 

[pblarus]

Re: Remedy for galled transom clamp screws

Thanks for all your posts.

I made some progress this weekend, first locating a set of replacement screws at a local OMC dealer who has been in business quite a long time and has some decent inventory of older stuff. Part number 433675, about $34 each! And I would still have the expense of the thread repair in the brackets, whatever that turned out to be. So I did not buy the screws, but did measure them and verified that they are indeed 5/8 NC (5/8-11).

I also found some used parts places that would sell me the entire bracket assemblies used for $35 per side plus shipping, screws included (I already had the brackets off to clean and lubricate the stuck tilt assembly so it wasn't a lot of extra work).

I did not try and locate a Heli-Coil in that size, though I'm sure they exist. Instead, I thought I'd try chasing the threads and seeing if they cleaned up enough to use. I did not try to find a 5/8 NC chaser, either -- bound to be very expensive! Instead, I bought a hex cap screw (under a buck) and made a thread chaser out of it by grinding two deep grooves about 3/16" wide, on opposite sides of the shank, the entire length of the threads. This gave a place for the chips to exit as I threaded the chaser in. This worked well since the steel chaser is plenty hard enough to work on the aluminum bracket. As bad as those threads looked (pretty bad), amazingly the bracket seems to have enough good thread left to hold well.

What I'm gonna do now instead of spending $78 on OMC screws, though, is use standard 5/8" bolts and put a spacer pad of StarBoard between the transom and the screw to protect the transom from the screw heads and vice-versa. And ... keep those things lubricated a couple of times a season!!