Suzuki 2.2DT outboard....the head is off, sheared bolt advice please

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FairweatherDave

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The minimal piddle on my outboard finally stopped altogether and I decided to go for it and clean out the channels under the head. Really amazed by the amount of crud (salt crystals and a jelly like substance) in the channels so looking forward to putting it all back together. This is despite religeous fresh water flushing after use. However in the process of getting the leg off the head one of the bolts sheared, (which I half expected from reading old threads here). Should I buy six new replacement bolts as I think they must all be weakened? Secondly would they be made of aluminium (do I need to get Suzuki bolts?). Thanks for any advice.
 
I have had a similar experience. It can be the devil's own job to get a broken bolt out with the use of penetrating oil and drilling for a screw remover.

I very much doubt they are aluminium - mine certainly weren't. A set of new ones seems a very cheap investment to getting it all back together.
 
They are just steel bolts. You need the right thread. I seem to think they are UNC. But it depends on how new the motor is.

This was my Tohatsu. One broken bolt.
Grind the stub flat. Centre punch it and drill it out. If you go off-centre, drill as big as you can without damaging the threads. Then use a tap to clean the rest of the debris out. You can make a cleaning tap by cutting lengthwise slots in a spare bolt and carefully screwing that in.


powwerheadgasketflange.jpg
 
Steel or stainless steel... I would have thought. They are stainless on my Evinrude

Id not have even thought of replacing them all unless steel and badly corroded
 
Thanks very much all. Exactly the replies I was hoping for! I can go to the Nut and Bolt store in Hove (brilliant shop/ no connection). Will replace all six as they felt like any could have sheared off.
The broken stud is protruding from the head so I am hoping I might be able to use some molegrips on it. Thanks Lakey for the advice on the thread stuff, could be very useful.

Final question.... the gasket is undamaged. When reassembling do I need to use any gasket goo type stuff?
 
Lakesailor said:
They are just steel bolts. You need the right thread. I seem to think they are UNC. But it depends on how new the motor is.

This was my Tohatsu. One broken bolt.
Grind the stub flat. Centre punch it and drill it out. If you go off-centre, drill as big as you can without damaging the threads. Then use a tap to clean the rest of the debris out. You can make a cleaning tap by cutting lengthwise slots in a spare bolt and carefully screwing that in.


powwerheadgasketflange.jpg
Click to expand...

They are 6mm, dont ask!
Stu
 
FairweatherDave said:
The broken stud is protruding from the head so I am hoping I might be able to use some molegrips on it.
Final question.... the gasket is undamaged. When reassembling do I need to use any gasket goo type stuff?
Click to expand...
If a proper head on the bolt wouldn't loosen it, molegrips stand no chance.

A mere smear of a decent gasket goo like Hylomar is all you need. Actually that powerhead gasket isn't particularly important as water or exhaust leaking will just go down the leg. Don't use anything on the head gasket. Get the faces clean with a scraper and 240-360 grade wet'n'dry on a wooden block. Use a new gasket if possible.
 
FairweatherDave said:
The minimal piddle on my outboard finally stopped altogether and I decided to go for it and clean out the channels under the head. Really amazed by the amount of crud (salt crystals and a jelly like substance) in the channels so looking forward to putting it all back together. This is despite religeous fresh water flushing after use. However in the process of getting the leg off the head one of the bolts sheared, (which I half expected from reading old threads here). Should I buy six new replacement bolts as I think they must all be weakened? Secondly would they be made of aluminium (do I need to get Suzuki bolts?). Thanks for any advice.
Click to expand...

Personally unless you are using a bench drill I wouldnt try drilling out the bolt, its steel into aluminuim so the drill will always head into the aluminuim, the minute it does that you are in a world of pain, take it to your nearest gargage , get them to mig weld a washer to the busted bolt and then weld a nut to the washer, while its still hot spray the bolt with WD40 or similar and using a rachet or spanner on the nut , work it back and forth graudually increasing the amount you turn the bolt, once youve made the full 360 you can slowly wind it out ....its all about the heat and expansion of differant metals

ive never had this technique fail (yet)
 
ribrage said:
Personally unless you are using a bench drill I wouldnt try drilling out the bolt, its steel into aluminuim so the drill will always head into the aluminuim, the minute it does that you are in a world of pain, take it to your nearest gargage , get them to mig weld a washer to the busted bolt and then weld a nut to the washer, while its still hot spray the bolt with WD40 or similar and using a rachet or spanner on the nut , work it back and forth graudually increasing the amount you turn the bolt, once youve made the full 360 you can slowly wind it out ....its all about the heat and expansion of differant metals

ive never had this technique fail (yet)
Click to expand...
Sounds a pricy way of doing things unless you can call in favours from the garage?

You certainly need to be careful when drilling steel bolts out of aluminium castings, but it can be done with a good drill and care. A cobalt drill and a good punch and a steady hand is a start. Begin with a smallish drill and you can 'correct a bit' as it goes in the first mm.

To the OP - if the casting does get mucked up a bit, find a friend with a heli-coil (or similar) kit. The kits are relatively pricy so its not worth buying one for a one off job unless you are working on some vintage classic engine that you really need to sort out...
 
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Someone always comes along and suggests an over the top way to expensively overcome a simple problem.
If you can't drill a stud out you are probably best not attempting to dismantle an engine. The relative hardness of steel and aluminium are irrelevant. Is that like saying if it were steel in steel you would rely on the the casting's threads to keep the drill on course?
For a little old engine, if the threads do get damaged tap out to the next size up and drill out the hole in the leg flange to accommodate a bigger bolt. There is plenty of meat available.
 
Lakesailor said:
Someone always comes along and suggests an over the top way to expensively overcome a simple problem.
If you can't drill a stud out you are probably best not attempting to dismantle an engine. The relative hardness of steel and aluminium are irrelevant. Is that like saying if it were steel in steel you would rely on the the casting's threads to keep the drill on course?
For a little old engine, if the threads do get damaged tap out to the next size up and drill out the hole in the leg flange to accommodate a bigger bolt. There is plenty of meat available.
Click to expand...


+1

Just take your time, [it's free to you], and start small and gradually working up in sizes, stopping when you get near the edge of the thread.
 
This forum is magic. Thanks for all the further advice,all of it is really useful and reassuring. I'd be taking it for an expensive service were it not for the advice I have gleaned here and elsewhere. I will let you know how I get on once I go for it. Next stop to cost up the appropriate sharp drills......(ouch, no doubt)
 
Lakesailor said:
Someone always comes along and suggests an over the top way to expensively overcome a simple problem.
Click to expand...
just thinking ..... could buy small bench drilling machine for less than what a garage might charge ????? Always a useful thing to have.
 
VicS said:
just thinking ..... could buy small bench drilling machine for less than what a garage might charge ????? Always a useful thing to have.
Click to expand...
I've never had a bench press drill that was entirely my own. I may buy one myself shortly as I am going to be undertaking a bit of an engineering project over the next few months.
 
Lakesailor said:
I've never had a bench press drill that was entirely my own. I may buy one myself shortly as I am going to be undertaking a bit of an engineering project over the next few months.
Click to expand...

Mine was £30 and is an industrial one I bought from a machine tool scrapyard. It needed a new motor (£5-00 from a friend) and I swapped the old slightly manky chuck for a new one from a workshop I knew at the time. That swap cost me a packet of biscuits... :)
 
Little update .Result! Thanks all. After wrestling with the broken stub and trying to grind 2 paralell sides to work on, all to no avail, I did what Lakesailor suggested and went in with the hand drill (cautiously, brand new drills etc). Wasted £3 on "easy-out"s and then kept on drilling bigger and bigger. Finally result, got the 35% thathad not been drilled to bits out and I still have a working thread (to my suprise). I am tempted to put a longer nut in on that one and a nut over the top. But what a pig of a job. Seems to have taken all day including buying the bits etc etc... Probably the heat from drilling helped the last bit maybe. I tried boiling water but was reluctant to gently warm with a blow torch with all the oils and gasket etc etc.

Would it be worth using the barium chromate paste on the SS bolts when putting it back together?
 
Just for information, if you ever have to do a similar job in the future, don't worry too much about the oils. It's surprisingly difficult to set minor smears of old oil on fire. However you might char a paper gasket so be cautious with the blow-lamp and please be careful with any petrol nearby! Otherwise you will have the answer to, "How do you make a rusty outboard fire?"
 
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