Yamaha 1991 broken bolts nightmare

pine island fred · Jan 3, 2006

Re: Yamaha 1991 broken bolts nightmare

Reading this post gives me a hollow feeling in my stomach! Tough knowing when to quit. Just dont order any new parts till you get the thing completely disambelled. By all means good luck. fred

Privateer · Jan 3, 2006

Re: Yamaha 1991 broken bolts nightmare

Andy- No such creature that i know of. I think he was just saying that oxy/acetelyne torch will always be more effective than any type penetrating oil.

Fjbango · Jan 3, 2006

Re: Yamaha 1991 broken bolts nightmare

I agree with you guys: Oxy/Acetylene are gases used in a torch (profesional grade), not a penetrating oil. THe most reccomended penetrating oil you find in this forum are: PB Blaster (You can get it at home depot, walmart etc) and the other one is Kroil (You can get it online). So far I used PB Blaster which was easier to get don't know Rodbolt's opinion about the Kroil. Would really like to send some pictures because the engine looks perfect from the outside, nice original yamaha paint, no trace of rust, even the records were amazing, I bought it in Aug'03 from original first owner, engine overhaul in 2002 (I doubt it was really done) for $2600.00 etc. BUT inside is another story. I am convinced this powerhead has not being removed in a long long time. No way it was "rebuilt" in 2002. I prefer to learn the lesson and spend my $ in a motor I know rather spend 5 times more in a used or refurbished one where the only thing I know is the word of the seller. ROdbolt, is there a e-mail I can send you some pics? I saw one e-mail address in one of your postings @ yahoo.com but may be old. Thanks again everybody... this place is awesome! and a great help for the "poor" boaters like me. I wish I could spend the big $$ and just buy a newer toy! Frank

andy6374 · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

Is a MAPP torch okay vs Oxy/Acetylene

tommays · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

MAPP might work sometimes BUT for the most part it heats things up to slowely to free badly frozen bolts theres a coupple of thousand degrees difference with the Oxy/Ace tommays

andy6374 · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

With these couple of thousand degrees differences... Do I have to worry about melting my aluminum block? I though MAPP was as high as you could go without worry although I could be highly misinformed.

Fjbango · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

I share the same fear about the hot Oxy/Ace, not only melting the Alu which is highly (heat) conductive metal, so the heat do not "stays" at the bolt and/or vecinity (salt and metal oxide are not that good conductors)it will reach other non metal parts like seals, gaskets, mountings etc. I have a mapp-oxy torch from any homedepot ($40) which uses a low pressure oxy canister ($7.00 last for 3-4 min approx) kind of a cheappy toyish tool but still can heat a bolt pretty good. This could work IF you apply the heat to the shank of the bolt, providing it is exposed. this way the heat travels through the shank into the threads and THEN crushes the salt, once hot, takt the flame out, (have an extinguisher handy just in case) and spray penetrating oil, others recommend parafine (from a candle) it will go inside by capilarity plus the vaccum of the cooling proccess and try to turn the beast at the same time. sometimes work sometimes not. That is not the same scenario as when all you "see" is the bolt's head and you need to heat the whole metal mass to expand it from the outside, here the heat will reach many other parts.

tommays · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

well your trying to heat the block to expand it and lossen its grip on the bolt with Oxy/Acc you can heat up a local area quickely and then work the bolt before the heat spreads to far if it doesent start moveing you need to wait a while and heat it up again you cant just heat it till it comes out or the block melts

it takes a lot of Patience to not break the bolt like i said before i have spent over and hour on one bolt ,but this is still much faster than driling tommays

Fjbango · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

Tommays: how far heating the block?, like it sizzles? or even hotter? I must confess I am afraid to do this. It will peel the paint and start to evaporate any trace of oil in the surrounding no? Thanks , Frank

tommays · Jan 4, 2006

Re: Yamaha 1991 broken bolts nightmare

thats wear it gets hard its a judgement call BUT it unlikely that your not going to dammage the paint buy the time you get it hot enough to get the bolt out if your worried find some junk parts and play this will give you a feel with how to heat things up also many times you will need to losen and tighten the bolt a small amount MANY times before it will start to come out tommays

Fjbango · Jan 5, 2006

Re: Yamaha 1991 broken bolts nightmare

Thanks Tommays, I get the idea. I am considering buy a "decent" torch, they sell brand new for about $250, for this money I could buy about 30 Oxy canisters at home depot, that will be enough. will check on e-bay anyways. Frank.

rodbolt · Jan 9, 2006

Re: Yamaha 1991 broken bolts nightmare

thats where it seperates the salt water techs from the non belivers. its very hard to actually cut AL with a cutting tourch as your heating a rather large heat sink. as far as the vertical slots as long as you dont hit a water jacket its of no concern. but cutting the bolts with a drill is a lot faster and easier. if you mess up the adapeter with anything else but external cuts,which are of no consequence, you have to remove the upper motor mounts to remove the adapter exhaust tube assy. its loads of fun but not particularly hard. like I say the fastest and best method is to cut the bolt with a drill just below the powerhead. use the bullet point non slip shank bits and its an hour or so operation and odds are you can alvage the adapter witout removing it. if you dont like the holes place a copper tube in them and have them welded back up. but like I say if you dont hit a water jacket the hole is meaningless. some welding supply places will rent oxy/acetylene penetrating oil kits

. we call the smoke wrenches and they are esential for saltwater motors. also look at some machine shop tool suppliers for drill bushings and I can explain how to make a drill guide that will hold your drill correctly and straight. as I used to be a machinist for some years its another tool most mechanics dont even know exist.

Fjbango · Jan 9, 2006

Re: Yamaha 1991 broken bolts nightmare

Thanks Rodbolt! I am not sure if you are 100% back active on the forum or still having some fun down there in venezuela.

I am still waiting for a local friend who is also outboard mechanic to have a look at the beast and tell me his opinion, see if he commit to help me with the task. I like your plan but, keep in mind that the 4 out of the 6 long screws are already broken so, the 3/8 drill need to do a clean cut since I have no grip on the head to turn and break the screws AT the drilled hole. Other question is on how high will I be able to drill this 3/8 hole, the lower cowling (still in place) will not allow me to keep the bit horizontal and still as close as possible to the powerhead. I am afraid that if I have to pull up the powerhead with 4 or 5 screw shanks (lets say 1 or 1-1/2 inch long) "still burried" and stucked inside the adapter, the whole thing will not budge and I will end breaking the adapter too (which could be necesary after all). I was thinking not to cut the groove with a torch, but to use a grinder first and later work the details with a dreamel and a cold chisel, this part is so corroded and the screw inside it is like "swollen", so the "vein" where the bolt is, is sort of "protuding" and cracked in some places. In one of the screws it was so bad that when I was tapping the screw it start to fall apart and exposed the actual screw in some of them. The whole picture is really ugly.

One good new is that I was able to loose all the small 4 screws going up from the adaptor plate toward the powerhead, the 2 nuts where never there. ALso the 4 screws from the adaptor plate downward to the "upper casing" are loose and can be removed. So the main problem is with the long six screws. I will post some pictures (tomorrow or the day after) I think the "Upper casing" (long part between the adapter and the lower unit) is already pretty damaged and will need to be replaced anyway. Thanks for not letting this thread die. Anyways, there is no way back, all the bridges are gone! Frank

rodbolt · Jan 10, 2006

Re: Yamaha 1991 broken bolts nightmare

no worries. the bolts are roughly 5/16ths (8mm) and a 3/8ths is roughly 10mm and if you have to go at a slight angle up its ok. if the drill bit is started on the bolt centerline just below the powerhead perpendicular to the bolt and the bit is roughly horizontl it will cut the bolt in two. thats why I like the bullit point bits from dewalt. they have 3 macined flats on the shank so they CANNOT twist in the drill chuck and cut flat. a standard bit has about a 113* angle and requires a lot of space past the bolt. the holes at the top of the adapter are twice the diameter of the holes at the bottom. thats why I said after ya get it apart drive the broken pieces upwards. you may wish to soak them liberally for several hours with chlorox bleach. bleach turns aluminium oxide and salt to a fish slime. best if the powerhead is mounted to the hull still as you will need a solid working environment. second best is to buy or make the tool that lifts the powerhead by the crankshaft. the tool replaces the flywheel nut and can be made with an old nut and some steel strap as long as it can hold 600 pounds or so. as there are no water jackets on the outer side of the bolts you can weld the holes you make or leave them be and maybe just fill them with a bit of (horrors) silly cone if it makes ya feel better. you will find that odds are the bolts are not stuck at the top of the adapter and most times you can remove the threaded portion with vice grips and maybe some heat once the powerhead is off. to make a drill guide. purchase the correct size guide. that will be the guide the size of the tap drill for the size fstener you will drill. use a piece of 1/4 or so flat stock about 1/2 or so wide. mill a slot down the center of the flat stock bout 4 inches or so. weld the flat stock to the drill guide. take it to machine shop. have the shop chamfer the drill guide on the side you will place on the block the size of the major thread OD for the fastener side then have them mill the assy flat so the flat stock is flush with the bushing and perpendicular to the centerline of the bushing. now you can carfuly center the bushing over the broken stud and use the slot with a fastener close by to lock it in place. now you can drill away happily without worring about off center bits. if the set up was correct the hole will be straight. if I am worried about drill depth I measure how deep I want the point then measure from the point to the depth on the drill and wrap that spot with black tape as a stop guide. a decent pair of dial or digital calipers is helpful. it sounds way more complicated than it is but if you have more than two or three to drill its a wonderful method. my buddy made me a few for 30 dollars each and I think the bushings cost me about 18 apiece at empire machine tool company. and that is how I drill the long bolts on the tstat housing without removing the water jacket cover. cause over the years I have found if one breaks a few more will most likly break. as far as melting the block occasionally I will heat the area around the bolt until it gets hot enought to allow the threads to come out with the fstener. this is especially useful on the pressure valve cover and lower unit bolts. if I can get the AL threads to strip and come out with the fastener its a quick easy job to helicoil and rethread.

Fjbango · Jan 10, 2006

Re: Yamaha 1991 broken bolts nightmare

I got lost on how to build the drill guide, from what I was able to understand it is not only the guide but also you "made" a tool for holding the guide. I will try to see if there are some for sale, or some real mechanic that can properly interpret your instructions and build one. Would it be too risky to do the holes just with bare hands? I have the DeWalt bits, a whole set, I might want to buy some 3/8" brand new to assure they are sharpened enough for the job. The hook: THe engine have a "lifting eye" /hook/ring whatever, located just a little aft the flywheel and between the both cylinder bodies. Not sure if it will hold the engine vertical, but it is placed there by the manufacturer and intended to be used for hoisting the engine. Is this hook-ring good enough? I will need a hoist as well. Lots of fun in 2006! Still waiting for my mechanic friend to come home for help/advise want to have some extra body handy if things turn uglier that what they already are. I am happy to hear that the bolt "jackets" are much wider upwards, Like you said odds are the "upper chunk" of the bolt shank will be free. I will try to drill about 1/2" below the Power head in order to have enough shank left to grab later for removal. Thanks again Admiral! Frank

Fjbango · Jan 10, 2006

Re: Yamaha 1991 broken bolts nightmare

You think something like this would work?? This tool is from a "woodworker" web page, not the same as metalworking... What's your opinion? http://www.woodworker.com/cgi-bin/FULLPRES.exe?PARTNUM=38166&LARGEVIEW=ON

rodbolt · Jan 16, 2006

Re: Yamaha 1991 broken bolts nightmare

the principle is the same. what you have to insure that the bore of the drill bushing can be locked in place in the same plane as the broken bolts centerline. dont try to remove the powerhead with the strap that bolts to the engine, it will lift the powerhead crooked and may wedge it tighter. either buy the lifting eye or make one that goes in place of the flywheel nut. imagine that bushing with a 6 inch slotted strip welded to it. that way you can use another bolt hole to lock the bushing down.

Ruafysh · Jan 16, 2006

Re: Yamaha 1991 broken bolts nightmare

Frank, Had a similar issue with my 93 225hp Yamaha. Read the original posting (at work on my way to a meeting) I had to drill out the lower two bolts on the head along with 4 others.. Did it without removing the lower cowling. I researched and found the smallest right hand 90% drill made.. Sears has it, used that and cobalt left hand stubby drill bits.. Started small, worked my way up and then took the remainder of the bolts out with dental tools.. Drilled, tapped, and used healy coils with all new yamaha bolts, gaskets, etc, and perfect seal.. Was in January last year, not sure if my post's are still out there.

Fjbango · Jan 16, 2006

Re: Yamaha 1991 broken bolts nightmare

Thanks for the last postings, I also have some news: THe outboard mechanic came to my home yesterday ad assesd the situation, He wanted to kick my behind badly. He said I shouldn't touch anything at all. Here is what i learned from him yesterday: First rule: If it is working and pushing your boat do not attepmt to do anything on an old salt water engine. Second rule: Do not attempt to remove any screw without an Oxy torch, when I showed him my "10 cent store" torch he smiled and repeated: I should kick your... you know. Third rule: you must have a decent lock pliers nor a pipe wrench niether a second-hand-got-it-at-the-flea-market-for-$1 type like the one I have. Fourth rule: heat & patience. Bottom line, mostly the same things you guys have been telling me since I started this thread. After all his speaches, more jokes about me and a couple beers and cuban coffee, he took my cheappy torch and cleanly took out 1 screw in about half an hour. He also lossened a little a 2nd one but my oxy cannister said "good-bye" and went empty. Also, in order to have horizontal access to the shanks at the bottom of the head cover, It wuould have been much easier and safer to drill a horizontal hole on the bottom cowling and later cover it with anything, rather than attempt to lift the powerhead. His advice: DO NOT loose any other screw! DO NOT check the conditions on the other head cover gasket. DO NOT continue trying to remove the power head, IT WILL NOT GO LOOSE! He says I have a chance to crack the powerhead if I am not able to lift it vertically OR if I am not able to cut the broken bolts cleanly. Even If by a strange odd I notice a little free play produced by regular vibratios, THEN I could try and see if it is free enough to allow a lifting. Other thing is to attempt to complete this job WHEN I have a major issue that justify to risk the whole powerhead. The powerhead will still hold by 2 of the long screws, the 4 small ones and 2 nuts, plus the 4 broken but still "salt-cemmented-rusted-source-of-the-nightmare" long ones. SO THis is the plan, I bought a set of 3 lock pliers (craftsman) and 4 bottles of Oxygen and will try next weekend. IF all this fails, well then I will continue with Rodbolt's strategic plan. Will post results. Thanks Frank

Fjbango · Jan 18, 2006

Re: Yamaha 1991 broken bolts nightmare

Although it is hard to believe, I typed "Broken bolts" on the google search engine and got over 1.8 millions hits! Here is the link to the results: http://www.google.com/search?source...&rls=GGLR,GGLR:2005-40,GGLR:en&q=broken+bolts On a quick browse of the results, I found a lot of pages of valuable Ideas. Many other are commecial advertising but still interesting. Frank

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