My old 7.5HP Mercury Outboard - again

[RIN]

I asked the forum for help on what to do with my old 7.5HP Mecrury outboard that I rediscovered at the back of the garage. Many thanks for the replies. I got it kind of working but it needs quite a few new parts which I can order from the US

It got very hot even with the telltale gushing away, so I took off the water cooled exhaust baffle plate. The chambers were pretty clogged and the baffle plate itself was so soft you could almost push a pencil through it. No problem there as I can get a new one.

Problem is that one of the bolts that hold the baffle and casing on to the block sheared off as I was removing it. Annoying but not terminal. I soaked it with penetrating oil and cut a slot on the protruding bit and tried to use screwdriver and grips. No good. Got out my stud removal kit and drilled into the sheared bolt, inserted the removal tool, turned the handle and crack, the tool split off in the bolt flush with the casing.

Now question is Should I give up at this point and bin it? I guess if it was working properly, the OB would be worth around £150 so its probably not worth paying to have the bolt removed, assuming I could find someone to do it - my garage was not interested.

Has anyone got an idea on how to remove it?

 

[Peanuts]

Hi Richard

Normally I would have said bring it down and I'll do it but of course you are leaving us at Poole to go to that place!!!!.You can still bring it down if you want and we will sort out the distance bit between us - any reason for a blast to Newton Creek.

I assume the hoover did not suck it out them - sorry I could not resist that.

 

[jfm]

I asked the forum for help on what to do with my old 7.5HP Mecrury outboard that I rediscovered at the back of the garage. Many thanks for the replies. I got it kind of working but it needs quite a few new parts which I can order from the US

It got very hot even with the telltale gushing away, so I took off the water cooled exhaust baffle plate. The chambers were pretty clogged and the baffle plate itself was so soft you could almost push a pencil through it. No problem there as I can get a new one.

Problem is that one of the bolts that hold the baffle and casing on to the block sheared off as I was removing it. Annoying but not terminal. I soaked it with penetrating oil and cut a slot on the protruding bit and tried to use screwdriver and grips. No good. Got out my stud removal kit and drilled into the sheared bolt, inserted the removal tool, turned the handle and crack, the tool split off in the bolt flush with the casing.

Now question is Should I give up at this point and bin it? I guess if it was working properly, the OB would be worth around £150 so its probably not worth paying to have the bolt removed, assuming I could find someone to do it - my garage was not interested.

Has anyone got an idea on how to remove it?

Bad luck on all that. A few random thoughts, which you've prtob already thought of!

1. could you extract the bit of stud extractor that's stuck in there, then drill the hole you've already drilled to the full length of the stud, then increase the drill sizes, then when it is finally out, drill and tap it one size bigger? Is there enough "spare"metal to take the next size screw up? Often there isn't with these precision die cast engine parts

2. Or what about just not using that bolt? There is only seawater pressure behind it, so would it seal with no bolt? Or clamp it some other way eg a massive jubilee clip right around the parts to squeeze them together at that point

3. Or, if you can extract the busted bit of stud extractor, just clean up the hole you've already drilled and tap it something like M4, then use an M4 set screw and large washer. As said above, there isn't much load on that screw if it is only seawater pressure behind it. Maybe put extra goo on the gasket

Good luck

 

[RIN]

Water is pumped from the galleries on the block into the space between the baffle (27) and the outer case (29) to cool down the baffle which takes the full blast of the exhaust gases coming out of the block so not only is there a lot of water in there but also (I think) high pressure from the exhaust so I would rather it be held on tight with the requisite number of bolts.

Yes if I can get the tool out, I can tap the hole I have drilled into the sheared bolt - I wish I had done that anyway.

Perhaps the best thing to do is to put it on the boat when we visit Poole next and see if Peanuts can do his magic on it. I bet he could fix my Hoover too