Old 6hp johnson

[bubbasblazer]

I have an old johnson 6hp probably from the 60's or early 70's?? maybe . The carb has the mixture screw coming out the front it and coming through the lower part of the housing. After replacing the waterpump and rebuilding the carb. It will not start. I am mechanically inclined and have set the float to be level with the bowl flange while upside down, turned the mixt. screw out from seat approx 1.25 turns, fresh fuel, ect. However after about giving myself a blister pulling the rope, it wont do anything, I have fire, Any ideas would be appreciated. Thanks

 

[tx1961whaler]

Re: Old 6hp johnson

Check the spark on both cylinders first.
Then check compression.
You can chuck up a socket in your drill to turn it over with the flywheel nut to keep your arm intact. Note that this is slightly dangerous.

 

[bubbasblazer]

Re: Old 6hp johnson

I have fire, my buddy said it ran when he put it up but had to play with the choke to keep it running, before I took it apart it ran for me for a few minutes but would not restart after it conked out, then came disassembly and reassembly and now it wont run at all.

 

[F_R]

Re: Old 6hp johnson

Never pull any motor till you wear blisters. You will only wear out your body, but the starter as well. If it isn't running after half a dozen pulls, there is something wrong with it. Or you are doing something wrong. So, stop pulling, already.

The next step is diagnosis. Never start pulling stuff apart till you know what is wrong. You can make things worse, then have two problems.

We can only guess what the problem is from here. Makes us look smart, but doesn't fix the motor.

Any internal combustion engine needs 3 things to run:
1. Adequate compression
2. Fuel and air in the correct amounts.
3. Adequate spark at the right time.
4. In addition, a two-stroke needs compression in the crankcase.

So, which are you missing?

 

[dcr42t]

Re: Old 6hp johnson

There are 3 seals which seal around the idle mixture screw/shaft. Did you replace these? If they are worn, it can suck air past the needle and run too lean and maybe not start.
This is what was wrong with mine anyway

 

[JB]

Re: Old 6hp johnson

I agree with F_R. Do not fix it until you know what is broke.

Go to the Top Secret File ^^^ and do the troubleshooting in "Outboard won't start".

Let us know what you find.

 

[bubbasblazer]

Re: Old 6hp johnson

I don't know what is missing the carb has fuel, the plug is sparking, and theres plenty of air around these parts of the world, yeah I replaced the seal behind the nut. I figured if somebody had to play with the choke to keep it running there was a fuel delivery issue. If you guys can come up with anything else please let me know. i'm off to the the secret file

 

[bubbasblazer]

Re: Old 6hp johnson

Got home from work and blew out all the passages and all is clear. Any idea on the reccomended gap for a jc8 on this old motor?

 

[JB]

Re: Old 6hp johnson

Wrong plug, Bubba.

Use Champion J4C or J6C gapped at .030".

The J6C is preferred for extended trolling, and the J4C for all-round use. The J8C is too hot for that engine.

What did you find when you did the "Outboard won't start" troubleshooting?

 

[samo_ott]

Re: Old 6hp johnson

Have you verified good spark with a spark tester?

Try spraying some 50:1 pre-mix into the carb and see it it coughs or runs, if yes then look at the carb again.

 

[bubbasblazer]

Re: Old 6hp johnson

Cool I will pick some of them up today as I work at the parts store. The ususal no start questions and. I did find a few reccomendations helpful. This site is a wealth of knowledge

 

[baldhunter]

Re: Old 6hp johnson

Sounds exactly like the problem I was having with my 67 3hp Evinrude.I rebuilt the carb and it ran perfect.Then I ran the carb dry and the next time I tried to start it,I had hell.Had a hard time getting it to start and when I did,it would only run with the choke on.This is what I found.At the bottom of the fuel bowl near the center is a high speed orifice.Mine has a brass orifice plug that requires a special tool to remove,so in rebuilding,I could never clean it well.I dug around in my tackle box and found some .025 dia. stainless steel solid wire leader and was able to work it through the tiny orifice.After working it back and forth several times,I could feel it cleaning the crud out that was built up inside of it.Put the plug back in the fuel bowl,turned on the gas,pulled the choke,pulled the rope and she fired right up!!!!!!!!! It now starts with only having to pull the rope a little over half way out and on the first pull everytime just like a new one.So it was that one tiny little orifice was giving me all that hell.I took it out for a test run,ran perfect for about a mile and quit.I paddled over to an island,removed the plug at the bottom of the carb.,ran the wire back through again and she fired right up and ran perfect for the rest of my outing.So that little wire,a paddle and a few tools is something I will not leave home without.

 

[bubbasblazer]

Re: Old 6hp johnson

I have some welding wire i will try and run through it thanks for the tip. Before work today I did get it running, I did have j6c plugs in it i glanced at the # last night and read it wrong. I did a NO NO and a quick shot of ether it fired right up and ran great, however it will not run if I turn it lower that "start" on the tiller, I put in "shift" and it wants to die out. BUT it will not restart without another quick shot of juice, i'm not real sure whats u with that. While looking for leaks on the motor I noticed small bubbles seeping outta the seam directly under the flywheel that runs up and down, I would call it a crankcase gasket, it is the gasket that mates the two halfs of the motor, I called a local johnson dealer and they said there was no gasket but a "gel seal" I'm hoping to put some rtv on the outside without disassembling the motor. Any thoughts on why it won't start without ether??