bad news today

[leafs]

today i took my 1974 johnson 70hp to get a new head gasket installed.the head needs to planed,and there is a bolt broken off in the engine,they say i have to take it to a machine shop to get it drilled out,is there a way i could gat it out at home.but the biggest problem is that the top cylinder is starting to score and it can not be bored out any more .if i do not fix the top cylinder how long will the engine last and will i damaged other parts by driving it

 

[ob]

Re: bad news today

removal of a broken stud will require some precission drilling.Unless you have adequate tools for this procedure and on hand experience with light maching skills I would reccommend you take it to machine shop.Ialso would never reccmmend anyone operate an engine with excessive cylinder wear issues.

 

[Dhadley]

Re: bad news today

How do you know it can't be bored? If thats true, you can resleeve.<br /><br />Good luck!

 

[sloopy]

Re: bad news today

re sleeving, sounds cool tell us more about that

 

[shaneb]

Re: bad news today

Depending on how stuck the bolt is, you should be able to use an E-Z Out. These bolts usually break because of lateral pressure caused by the uneven heating of the block and head. Usually not because they are frozen. <br /><br />do this: take one of the other head bolts to a hardware store (one with a good tool selection not Home Depot or Lowes Please!) tell them that you have a bolt broken and you need an EZ Out and drill bit. <br /><br />The EZOut is kind of a reverse thread self tapping bolt. you drill a hole dead center in the broken bolt and thread the EZOut into that hole, when the EZOut bottoms out, you should be able to back the bolt out. <br /><br />If you are taking the motor apart you don't need to worry about shavings. But if you are not going to rebuild the motor, cover both the EZOut and the drill bit in heavy axle grease and drill/tap very slowly. This will catch the metal shavings and keep them out of the motor. <br /><br />This is always a better option than drilling and tapping a head bolt hole. <br /><br />Good luck with it. <br />Shane

 

[mrc]

Re: bad news today

resleeving involves reboring out to a "much" larger size, then bonding a new<br />sleeve for the piston in the hole. Bout all the details I know at this point,<br />hoping I don't have to learn more <br /><br />Mike

 

[ob]

Re: bad news today

that's the key. drilling dead center on a broken stud with more than likely an uneven face.without drill brackets or mag bases becomes difficult to perform.don't forget to center punch if you're going to attempt to drill.

 

[rlouns]

Re: bad news today

I had 5 bolts break off in the block when I tried to remove the head on my 1991 90 HP FORCE.<br />I tried getting them out as described above and broke the easy out off in the bolt. Luckily that bolt hole went all the way through the block and I was able to get behind it and (after making a unique tool) drive it out. I then had to drill each bolt hole and tap each one. And they are right when they say do not attempt this if you are not experienced. I could not get a straight shot at the holes and wound up reaming the holes in the head to allow room for the mis-drilled bolts to tighten with the head seated. If the one cylinder is worn past the point of reboring you might consider a new power unit (engine).

 

[Dhadley]

Re: bad news today

Leafs - you still out there?

 

[leafs]

Re: bad news today

thanks for all of the advise, i took the boat to a differend boat mech he says he can get the bolt out about a hour labour and to install one new sleeve is 500.00,so i am not sure what i am going to do

 

[dmessy]

Re: bad news today

28 years is good life for an outboard. Part er' out and start anew( or a-used!)

 

[Dhadley]

Re: bad news today

Let me try again. Why can't it be bored?<br /><br />??????

 

[leafs]

Re: bad news today

he said its been rebuild before,and its been bored out and over sized pistens were put in so it can,t be bored out again and just a new sleeve is 500.00 canadain. i got the boat back with the new head gasket seem to run real good,so i might just drive it tell it blows.i did a compression test 125 125 130.so that fixed the low cylinder.but i did a compression test with the engine cold how much of a difference is it to do the test when engine is warm?

 

[Dhadley]

Re: bad news today

It depends on what pistons are in it now. If they are .020's you can go to .030 or .040.<br /><br />Sounds like the compression is pretty good. Im glad you got it going.<br /><br />Good luck!

 

[sloopy]

Re: bad news today

doesent that increase engine heat? I like the idea of re sleaving so you can take pictures so I can see

 

[Greg Lawrence]

Re: bad news today

i have a 60 hp jhonson, and i have .030 pistons. so we took all the bores, bored them way out lik eprobly to .125, and put a new sleeve in to each bore. then they bored the sleeves to .028 and honed to .030.. of course your clearance is built into the piston... its not really an exact fit. Hey look here. you need to re-tourque your head bolts with a tourque wrench after you heat cycle that thing or you will blow another gasket. I got my new gasket last month ran it a few times, and got probly two full turns on each bolt till each seated at 18 lbs! i know they were tourqued to 18 lbs to begin with because i watched the mech do it!

 

[Greg Lawrence]

Re: bad news today

you could also get some real nice wiseco pistons in a std bore size and resleeve the bore to a std bore! that would be like a brand new engine, PLUS the block is already seasoned and it isnt going to be moving around.

 

[sloopy]

Re: bad news today

good Idea greg