1969 Johnson 4hp impeller

[oldcatamount]

I took off the lower unit and tried to take out the two stainless steel screws that hold the pump cover. They both were stuck bad. I believe this is the original water pump and has never been serviced. (I worked for a half hour just to get the pump cover to release from the casting). So, the two screws twisted off. I'm not really sure they are stainless steel as they both broke fairly easy. Then I drilled down through both of the remaining screw shanks with an eighth inch drill bit, then again with a three sixteenths drill bit and got out the remaining screw shanks. Then I was left with two oval shaped screw bolt holes that I packed in some more JB Weld putty. The next day I drilled and tapped out the filled holes and finished the impeller replacement. After all of that, the impeller job took me four hours. This may sound like an advertisement for JB Weld but, for the problems that I run into, it's good to have around.

 

[emckelvy]

Re: 1969 Johnson 4hp impeller

Next time you run across stuck bolts/screws, use some heat from a propane or MAPP torch followed (after cooling) with some penetrant (PB-Blaster is great) to help break them free.

Salt and other deposits build up on the hardware and this locks them in place. The heat expands the part so you can get the stuck bolt/screw free.

Worst case, it's best to drill the heads off then use a bit more heat to get the housing removed. Then you can use heat directly on the stuck fastener, also you can get the penetrant directly on the threads. And you can use a pair of Vice Grips on the busted 'stub' to help work it out.

Worse come worse, when you have to drill out busted hardware, a better repair than JB is to drill out then Heli-Coil. The stainless inserts grip well and the fastener usually won't seize up in the threads again.

One good tip for pump screws etc to keep them from getting stuck again is to use a thin coating of Permatex #3 Aviation-type gasket dressing on the threads. The 'gasket goop' makes a salt-resistant barrier and even if stuff gets in, a little heat and it'll release easily.

The Permatex also works great on head bolts and exhaust manifold bolts, amongst others.

I've repaired stuff with JB before and in the right application, it holds well. Just keep an eye on your water pumping and she should be OK. If you have issues in the future, a Heli-Coil kit for the #8 or #10 screws in your pump isn't that expensive online.

HTH & Happy Motoring.........ed

 

[oldcatamount]

Re: 1969 Johnson 4hp impeller

Thanks Ed, I was reluctant to put heat on the casting, but next time something like this happens, I'll try it.

 

[tx1961whaler]

Re: 1969 Johnson 4hp impeller

I have a 3 HP with one JB welded water pump screw hole. Been that way for quite a while with no issues. Since I use Permatex to seal the plate and housing down, I don't think there's too much stress on those particular screws.