Bubbleback thermostas, bolt broke.

healey8390

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I have an 86' 110 Johnson. The left head was cooler than the right side so I figured it was an open stat. Tore it down, took the back cover below the pan off, took the "bubble" manifold off and that made it way easier to access the housing. Ironically, the only bolt easier to get to by taking the manifold off was the one that broke, the middle one. There is a little sticking out so I do have a punchers chance with an extractor but if I can't get it out will I be able to get away with just the outer two? I'm really hopings so and thinking that since it's not a pressurized system like a car that it may work. On a side note, the stat for the cool side does not look stuck open so I don't know why that side was cooler but given the age of the engine it was time anyway. I think I'm going to do deflectors to while I'm working on it already.
 

boobie

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Was this a bolt for the manifold or the thermostat housing ??
 

emdsapmgr

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You'll know if it leaks when you put it back together and run it. When you get the heads off to do the deflectors, you will see how clean (clear of debris) the water passages are around the cyl liners. Make sure the deflectors go back in the correct position-the middle deflector in this picture is positioned correctly and the water passages are like new. misplaced diverters.jpg (The one to the right is out of position.)
 

boobie

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I'd try and get it out. Less chance of any leaks. What ever you do don't try E-Z Outs. If you break one of them off in the bolt, you're really screwed. Left handed cobalt drill bits really work good. Start small and work your way up. A lot of times they will grab and the bolt will pop out.
 
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healey8390

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Thanks for the idea Danny. I had a friend with a small welder come over and we had no luck, tried about 5 times. It kept breaking more of the bolt off. Before me it was a fresh water motor so I find it hard to believe it's stuck that good.

I have no choice to pull the power head and take it in now. I can do it but I don't feel like it if you know what I mean.

I learned my lesson the hard way with a tap on my Chrysler lower unit so I know what you mean Boobie. Was water pump housung bolt hole, tap broke inside. Was lucky to get away with three bolts, motor never overheated. Don't think I'd be that lucky on this given the pressure at WOT.
 
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healey8390

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Can't you get at that bolt with an angle drill ??

Possibly, I'd have to cut the bit down. My worry is being able to drill into it square. I did some drilling and taping on my chrysler tilt and trim, the cap that goes over the trim piston. I had that off and wasn't able to get square. Luckily it didn't mater because it just had to hold the cap down so the angle wasn't too big of a concern. But with this housing I have to be dead on for everything to line up!
 

healey8390

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Ok so I got the powerhead off and I didn't know it but the thermostat housing stays on the mid leg. I'm not going throught the work of taking that apart and in but I have free access to fix it now.

Boobie, I'm gonna try the left handed cobalt bits. Wish me luck!
 

Fed

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So that let you lift the lower pan off to get a real good go at it, we all like pictures you know.
I think you will have a ground strap that goes from the transom bracket to around the engine mount somewhere under the powerhead, mine sort of corroded off so you should check to make sure yours is in very good condition.
Has been on my maybe to do list for years now, lot of work for a 2 bob bit of wire.
Is there any bolt sticking out at all?
 

boobie

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Start small and work your way up. If you get the hole in the bolt big enough you might be able to pop the remainder out with a pick.Then run a tap in the hole to clean up the threads. The left hand turning of the bit may also pop the bolt out. Just take your time.
 
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V153

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Before you get any more carried away. Soak the crap outa it for a few days with penetrating oil. PB Blaster, etc. Provided you haven't already broken the bolt off flush that is. But even so it'll make getting what's left out easier.

Never ceases to amaze me what a lil patience and copious amounts of penetrating oil can do to a stuck/broken bolt. A lil heat'll help too.

Apparently that middle bolt is the one that likes to break. Always seems the hardest to get out. I've seriously twisted them before but thankfully never broke one.
 

Fed

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100% agree with your above post V153.
He could even make a little dam to fill with the penetrating oil.
 

healey8390

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The surprising thing to me about the pan is that the powerhead is what holds in on, as soon as I took it off the pan pivoted down. There was no ground strap in that area for me Fed.


Not that this was "fun", I think removing the powerhead is the easiest way. Looking at it from an efficiency standpoint, in the time I spent trying to weasel in there and taking the bubble off, I could of had the powerhead removed or close to it.

I'll be sure to soak the you know what out of it! Trust me.

Boobie, the lazyness in me has got me wanting to try an extractor so I don't have to drill multiple times. I found this irwin one that is made of steel, would you trust that?
 

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healey8390

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Couple more pics.
 

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Fed

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Thanks for the follow up & pictures Healey I'd be trying the soak & heat before drilling holes, looks like there's still some bolt sticking out?
A very long time ago one of my suppliers told me the best way to remove stuck broken bolts is to heat the bolt to just red hot and allow to cool before trying to remove. I've never had reason to try it but very interested in what others think of this approach.
I guess the question is how hot is red hot and what temperature does aluminium melt at?
I'm not advising you to try this simply mentioning it to see what others think.
(The guy was a pretty clever bloke)

Keep up the progress reports, I'd like to service the t'stats on my crossflow 90 but not enough to pull the powerhead off.
 

V153

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Ground wire should be attached to the #3 inspection cover. (Bottom cyl, stb side.) There's a boss in the pan specifically to connect it to.

I dunno bout the "cook the bolt method". Seems to me the surrounding aluminum would cool faster than the steel. So you'd kinda be back where you started?

Not that it'd hurt anything I guess. But I think the whole idea is to expand(heat) the surrounding material so it'll loosen it's grip on the cooler fastener. Theoretically ...

Judging by the pic it looks like ya got enough sticking out to grab hold of. Definitely soak the P outa it beforehand. Can't stress this enough. Took decades to get it through my thick head. Might wanna tilt the mid up so gravity can give you some help?
 

Fed

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I dunno bout the "cook the bolt method". Seems to me the surrounding aluminum would cool faster than the steel. So you'd kinda be back where you started?
I think it's more like after it cools you're back where you started but you've cooked the crud in the bolt thread.
 
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