76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

[400hphemi]

Does anyone know the size of the bolt or weather it is standard or metric? How would I go about fixing the problem? PLEASE PLEASE Help me!!

 

[400hphemi]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

oh yea the model number is 35e76g

 

[F_R]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Wow, second same question in one day already.

I can't say for 100% sure, but it probably is a standard SAE (fine) thread, fractional. Measure it as close as you can. It probably is a 9/16". 1/2" or 5/8" would be far different, so it should be easy to decide.

 

[Tim Frank]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

If the crankshaft nut is stripped, just buy a new one.
Assuming that the crankshaft thread is repairable (if it is not, the problem is substantially more of a challenge..) take the new nut to a tool supply house and get a hex die that matches the nut.....from FR's post, probably 9/16-18NF but maybe 5/8-18NF or 1/2-20NF. Use the die to chase the thread on the crankshaft.
You might be able to use a needle file to clean up the thread, but a die gives a more predictable result.

 

[CATransplant]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

If you use a die to fix the threads on that crankshaft, it is very, very important that you get the die started on the threads properly. If the threads at the end of the shaft are damaged, it can be very difficult to get the die started.

If the die is not started so that the threads are correct, you will ruin the crankshaft threads. Since the die is designed to cut threads, it will cut the wrong threads easily.

Personally, I think that if you're not familiar with this tool, take the new nut from the dealer and the outboard or powerhead to the machine shop and let them do the thread repair. The money it will cost (not all that much) will be more than worth it if you try and mess up the threads beyond repair.

Good luck with your engine.

 

[bonz_d]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

In stead of a die look for a thread chaser of the correct size. They are designed just for this purpose and will not undercut the exsisting threads. It looks like a die but it's not!

Maybe be at a tool rental place or try Craftsman.

 

[Tim Frank]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

On further review...
CAT's advice may be the most sound.
If you have not played with taps/dies before, the potential for turning a small problem into a disaster is too real.

 

[R.Johnson]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Before you buy a die, or a thread chaser, try this test first. Try a good, sharp file on the crank. Do this at the top of the crank to see if the file will cut into the crank, or just skate across it. The crank shaft will be hardened, just how hard I don't know. If a file won't cut into the crank, neither will a die, or thread chaser. If a die will cut into it, I'm betting it won't turn easy. You will somehow need a secure hold on the crank, and a good thread cutting oil. You don't won't the die to friction sieze on the crank. Then you have a real problem.

 

[freddyray21]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

machine shop

 

[R.Johnson]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

A machine shop would be the best answer. They may well ask that the crank be removed from the engine.

 

[bonz_d]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Seems to me that the cost of removing a crank, machine repair and then reassembly of that engine is more than the value of the engine.

CA's post wasn't there yet when I started to make my post which is why I suggested the thread chaser over the die and for the same reasons as CA stated.

I have used thread chasers on some pretty messed up shafts, including Stainless Steel, with very good results because again that is what they were designed to do. Repair threads.

Though if you do not have the skill or just feel uncomfortable doing it the best bet would be a repair shop.

Best of luck and let us know how it works out.

 

[Randybeall]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

One more option which is an add on to the thread chaser is a thread file. This is a file like tool which has thread teeth cut into its sides. You must determine which thread pitch is correct and then use the thread file to draw across the threads of the damaged part to clean them up. Done gently and correctly it will allow you to start the thread chaser or die correctly to get acceptable results. Prehaps it is time for a Craigs List engine and rebuild yours with combined parts?

 

[400hphemi]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

I found out the size nut i need for the crank it's (1 1/16" flats x .45" w/ 58 nf thread..now the prb is i have no idea what the hell that is..if i go to lowes what should i ask for?:redface:

 

[karlow1]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

That's a problem, a 58TPI thread file is not going to be common.
Do a search on line, I think you are screwed! The thread file was your best solution. The other solutions sound like get a new crank, send your crank out to be welded, turned, and re-threaded. Or maybe turned down to the next smaller size, and treaded. It all sounds like $$$ to me.
I might try something else first, Get the right nut, cut it with w hacksaw. Then I would slip it up stream of the damage, and use it for a die. It might work.
Good luck.

Kp

 

[1946Zephyr]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Well, if any machine shop asks you to remove your crank, just to chase some threads, tell them to take a walk. It's not that hard to do and a good craftsman can do it with his eyes closed. A thread chaser is your best option and will likely reduce the worry of messing things up.

Leon

 

[CATransplant]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

58 threads per inch? I don't think so. Where did your information come from?

That's a finer pitch than anything I've ever heard of, and for a shaft that size, it's ridiculous.

Take the thing to the machine shop and let them have a look at it. You can get a new nut from a dealer or from an online source like www.ishopmarine.com. The part humber is 0321341. Cost will be under $8.

From your posts, it sounds like you're not an experienced mechanic or machinist. Nothing wrong with that. But, given the cost of messing this job up, the machine shop is the right choice.

They'll have a thread pitch gauge and will be able to restore your threads for you. I can't say how much it will cost, but you won't have to disassemble the powerhead, either. It won't be all that much, compared to what it will cost if things get more messed up.

I guarantee that it isn't 58 threads per inch, though. Nobody uses that fine a pitch on that size of shaft.

 

[Tim Frank]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

58 threads per inch? I don't think so. Where did your information come from?

That's a finer pitch than anything I've ever heard of, and for a shaft that size, it's ridiculous.
You can get a new nut from a dealer or from an online source like www.ishopmarine.com. The part humber is 0321341. Cost will be under $8.

They'll have a thread pitch gauge and will be able to restore your threads for you. I can't say how much it will cost, but you won't have to disassemble the powerhead, either. It won't be all that much, compared to what it will cost if things get more messed up.

I guarantee that it isn't 58 threads per inch, though. Nobody uses that fine a pitch on that size of shaft.

How did you "find out" ?
>>>I found out the size nut i need for the crank it's (1 1/16" flats x .45" w/ 58 nf thread..now the prb is i have no idea what the hell that is..if i go to lowes what should i ask for? <<<<

CAT is bang on...No way it is a 58 TPI fastener in that diameter! A #2 machine screw has only 56 TPI and you can hardly see those threads they are so fine...

So, if the nut is really 1 1/16" across the flats it is classed as an Amercan Standard heavy hex nut, and it is a 5/8 thread nut. Fine pitch thread would be 18 TPI, coarse 11 TPI. It is not a "special" but is not a standard hardware store 5/8" nut either. I am not really familiar with Lowes, but they seem like Home Depot....and you MIGHT get it at HD...or not....probably would need a specialty fastener shop, and the nut might be $2-$3
But we are getting academic, because you are likely to have more trouble trying to determine the thread pitch, to answer your question "if I go to Lowes what should I ask for?"....you should ask for directions to the nearest OMC parts supplier and buy the proper nut "You can get a new nut from a dealer or from an online source like www.ishopmarine.com. The part humber is 0321341. Cost will be under $8."

 

[400hphemi]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Ok thanks for your guys advice il just order the nut have the threads fixed by a shop ...then maybe the old boat will be ready to get me to my hunting spots

 

[CATransplant]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

Good decision, I'm sure. Let us know how it works out.

 

[400hphemi]

Re: 76 Johnson 35Hp stripped crankshaft nut and damaged crankshaft thread

alright i got that fixed got the boat out on the river and it will top out now but not long after wot it gets a bog and it will shut off if i hold it at wot but if i let off the gas a lilbit it will run fine and on both plugs and on my way back to the boat ramp it ran fine at wot for about 5 mins and then i could hold it at wot but it would power up then back down over an over like a baaaaaaaaaaaaaaaa baaaaa baaaaaaaaaaa if thats helps any but then if i back it off wot it will run fine any ideas of what i might need to check thanks alot for all yall helps she's all most there