4hp impeller housing bolts stuck

[curtis4769]

Hey guys, I picked up a seized 70 johnson 4hp to use for parts for my three other 70's johnyrude outboards. I completely stripped it last night including removing the powerhead so it's all in parts (it was a great learning experience; factory service manual helped a lot)

Anyways, the only bolts I couldn't loosen were the 2 flat head bolts that hold on the impeller housing. I banged on it with an impact screwdriver but no luck. I can't heat them because the impeller housing is plastic. I have some PB Blaster, but am concerned because of the plastic, it even says on the bottle that it can damage plastic. So my question is how would you proceed? Will the PB Blaster screw up the plastic housing?

 

[boobie]

Re: 4hp impeller housing bolts stuck

You may have to sacrafice the impeller hsg to get the bolts out. What you don't want to do is break the bolts off in the lower hsg.

 

[curtis4769]

Re: 4hp impeller housing bolts stuck

I've been spraying the pb blaster and whacking them. We'll see. I may have to sacrifice the housing, or cut the heads off the bolts and remove the housing.

 

[Mas]

Re: 4hp impeller housing bolts stuck

Apply some heat (propane torch) to the outside housing below the screws. The heat will allow the PB to penetrate better and expand the metal...just not so much heat as to burn the paint if you're trying to save the factory paint. Then a few wacks with the impact driver.

Mas

 

[curtis4769]

Re: 4hp impeller housing bolts stuck

Wow, I have never encounter bolts this stuck in my life. Used the propane torch below the impeller housing, then added pb blaster, and finally impact driver.......nothing. I did this cycle probably 10 times over. I don't think they are coming out, but I'll give it a shot again tomorrow.

 

[Mas]

Re: 4hp impeller housing bolts stuck

....I cannot imagine SS that stuck. They should break before giving that much of a hassle.

Mas

 

[Mas]

Re: 4hp impeller housing bolts stuck

Are you using the old fashioned impact driver?...the one requiring a hammer??? If not, that's what you need!

Mas

 

[curtis4769]

Re: 4hp impeller housing bolts stuck

Mas, yes I am using an impact screw driver that you smack with a hammer. I honestly can't believe the bolt hasn't broke off yet.

 

[boobie]

Re: 4hp impeller housing bolts stuck

You need a hotter torch. Mapp Gas or ACY/OX.

 

[curtis4769]

Re: 4hp impeller housing bolts stuck

Ahhhhhhhhhh.......sweet success. Finally got one out. The other finally snapped the head off. I could then remove the housing and get the pb blaster right onto the threads. Some more heat and some vice grips and now I'm back in business

 

[Mas]

Re: 4hp impeller housing bolts stuck

As long as you're able to get the broken one out, I'm happy to hear your news. Make sure you add some product to the threads upon installation to prevent corrosion next time. I use OMC gasket sealing compound.

Mas

 

[curtis4769]

Re: 4hp impeller housing bolts stuck

mas, I got the broken one out no problem with the vise grips after heating and pb blastering the bolt several times. No problem once the impeller housing was off, I think this motor must have been in salt water because here in Colorado I've never seen bolts seize that bad.