1973 Johnson 9.5 hp carb rebuild

[MrGED05]

Sirs:
I recently purchased this outboard. After much effort, I've repaired the transmission and replaced the impeller. Now I've managed to get the motor to run but very badly, it needs about half choke to keep running and won't pull WOT revolutions as it should.
Carb rebuild in process now. I ordered the manual, it should have gotten here Friday. It didn't. Naturally. I reserved today to do the rebuild (I bought an original Johnson carb overhaul set: gaskets, needle valve and seat, jets, the whole package)
Since I have today to do the job, I started pulling the carb. First off was the flywheel (bought a nice gear puller so I could use the tapped holes in the flywheel instead of taking a chance of damaging the starter rope channel or the starter teeth). I've removed the bolts I can access.
The spring loaded, flexible shaft choke mechanism is new to me, I've no idea the proper way to disconnect and remove it. Also, any hints on proper float settings and such would be appreciated.
Anyone care to share some advice with me?
Thank you in advance,
Gary

 

[stl]

Re: 1973 Johnson 9.5 hp carb rebuild

The float should be paralell to the surface of the carb if you are holding it horizontally. If not you can bend the float tab with a needle nose pliers to the correct position. I dont recall how the choke lever went but I will go look.

 

[stl]

Re: 1973 Johnson 9.5 hp carb rebuild

My choke lever on my 65 is different than yours so I got this from the book. Remove the knob on the front of the engine and turn the flexible cable counterclockwise until the needle valve is removed from the carb. Hope that helps

 

[MrGED05]

Re: 1973 Johnson 9.5 hp carb rebuild

STL,
You, sir, are one smart cookie. I'd just logged on to correct my first posting on the Johnson 9.5. I'd been out in the garage trying to figure out the secret to removing the "choke" when I noticed that I'd already removed the choke arm, it is the lean/rich adjustment that is spring loaded into the carb body.
I'll take off the knob, turn it counter clockwise until the needle valve comes out.
I'm guessing that on re-installing the carb, I'll need to run the needle valve gently to fully closed (clockwise) then back it out one full turn before re:connecting the lean/rich knob. Is that correct?
Thank you for the magical ability you must have to be able to read what I meant to write instead of what I actually put into words.
Remarkable.
Thanks again, ever so much.
Gary

 

[stl]

Re: 1973 Johnson 9.5 hp carb rebuild

The needle valve should be installed after the carburetor is in place on the engine. Check to be sure the snap ring is in place and install the spring, washer and new o ring. Thread the new needle valve in until it just barely seats then back it out 1-1/2 turns. Then check out Joe Reeves post on carburetor adjustments. I think it is FAQ section

 

[joho5]

Re: 1973 Johnson 9.5 hp carb rebuild

I have a 9.5 as well and it was running very badly and so I did a carb rebuild, and it made all the difference in the world. running like a champ now.

Matt

 

[Vic.S]

Re: 1973 Johnson 9.5 hp carb rebuild

I think it is FAQ section

In the "Engine FAQ " first item on the "Repair and maintenance" Index.

 

[Shildy]

Re: 1973 Johnson 9.5 hp carb rebuild

DO you have to remove the fly wheel to get the carb off?

 

[ezeke]

Re: 1973 Johnson 9.5 hp carb rebuild

To Shildy: You absolutely do not have to remove the flywheel to get the carburetor off. You do need to rotate the tiller arm so that you can reach the fifth screw on the carburetor.

 

[Shildy]

Re: 1973 Johnson 9.5 hp carb rebuild

Thanks a lot for the quick answer. I didn't think so, but after reading some of the post on here I was wondering. Would I need to remove the lower part of the carb to get it really clean? Or could I just remove the top half and give it a good once over? My 9.5 runs but only with full choke, and only about half speed when fully open. So I'm thinking its a dirty carb. Thanks.

 

[ezeke]

Re: 1973 Johnson 9.5 hp carb rebuild

You need to remove the float bowl with the top part of the carburetor so that you can get to the high speed orifice which is behind the drain in the float bowl. The new gasket between the carburetor and the intake comes with the kit.

 

[MrGED05]

Re: 1973 Johnson 9.5 hp carb rebuild

Shirley,
I just found it more convenient and easier to check the ignition points and capacitors at the same time as doing the carb rebuild. And, it is a bit easier to get at all the carb fasteners with the flywheel out of the way. I also think it desirable to soak the entire carb body (absent any rubber or cork gaskets) in carb cleaner overnight. I used a stiff new toothbrush to get everything really clean and also used compressed air to be sure all the fuel passages were completely clean. Be sure to wear protective eyewear when using compressed air with carb cleaner, that stuff can cause a real problem if it gets in your eyes. Side note, the points on my motor were "blued", I didn't have to replace them, just polish them up with a super-fine fingernail buffer and re-set the gap. Additional note, my particular engine preferred a slightly leaner fuel/air mix than some otheres, backing the needle valve out only one turn put the adjustment within range of the exterior knob for starting and throttle response.
Good luck, just a few more months and we can go back out and play on the water !
Gary

 

[Woodstock60]

Re: 1973 Johnson 9.5 hp carb rebuild

Just want to give one small word of advice, I picked up an old and fairly beat up 9.5, running the same. wouldn't stay running unless I choked. Rebuilt the carb, no luck, tried another carb, no luck. Tried a third carb from a good running motor- same thing. I pulled off the flywheel and re-gapped the points, bingo. she ran great, seems the first gap was too tight. Getting the correct gap is crtical. Ronnie

 

[Shildy]

Re: 1973 Johnson 9.5 hp carb rebuild

Thats sounding like my problem. I just finished cleaning the carb, and its still coughing at low idle and needs the choke to stay running. I'm going to play with the 'mix' needle tomorrow. But is there a walk though on setting the points?

Thanks

 

[Woodstock60]

Re: 1973 Johnson 9.5 hp carb rebuild

Fairly easy, first pull off the spark plug wires and flywheel, inspect everythig while your there, coils and wires should look clean and fresh. No dried out plastic or cracking, flaking rubber. Make sure the points are dry and clean looking if not you can resurface them a very fine file, but they are cheap enough if there's any question but a kit, comes with condensers too.( not the coils they are more expensive). Ok some once your confident with the quality you will need a feeler gauge, fairly cheap at your local auto parts store, maybe a couple bucks. Turn the flywheel clockwise, never counter clockwise or you can kill your impeller,until one side of the points are fully open, the butt side of the point pivot should be on the spot marked "TOP" of the cam. loosen the lock down screw on the back of the points so you can adjust. use the arm on the feeler gauge marked .020 and slide it between the points use the adjustmedt screw to tighten or loosten as needed. The mistake I believe I was making was I would snug the points down on the gauge and tighten the locking screw. I believe you have to let that gauge fit in there freely just barely touching the contacts and then lock down. The gauge should not be tight nor too loose, I think that is the critical measurement that will allow for good timing and make the engine run smoothly. Let me know how you make out with this.

 

[Shildy]

Re: 1973 Johnson 9.5 hp carb rebuild

Im starting to think it's the fuel pump. I've replaced the spark plugs and its still needing full choke to run. So this makes me think its needing the choke to suck fuel into the carb, is there a way to bypass the fuel pump or test the fuel pump? Thanks Guys.

 

[joho5]

Re: 1973 Johnson 9.5 hp carb rebuild

If gas is getting to your carb, then your fuel pump is working. Just check your primer bulb as the motor is running and see if it is staying tight.

It sounds to me like it could be 3 things

1. leaky fuel lines (which leaks / sucks air)
2. still dirty carb (make sure and pull it apart, soak it over night with all plastic off of it, then spray clean orfices and holes with carb cleaner, then shoot all the holes and orfices with compressed air) That is on top of installing the carb rebuild kit
3. your lean / rich needle isnt set correctly.

 

[ezeke]

Re: 1973 Johnson 9.5 hp carb rebuild

The fuel pump just fills the float bowl and keeps refilling it; after that the pistons create the vacuum to pull the fuel through the carburetor. If the leaf block assembly is in good shape, check the high speed jet again and blow out the capillary behind it.

If the lean/rich/ needle is not open enough, you would have to make up for it by using the choke, so you might want to check that the seat for the needle is clean and clear.

 

[Shildy]

Re: 1973 Johnson 9.5 hp carb rebuild

Again, Thanks for all your input. Joho you might be onto something.. The gas line from the fuel pump to the carb had a small split in it and was spitting some fuel when the motor would cough... So I trimmed off about 1/4" and refit it to the carb and noticed it looked a little old. That might be the fix. I'll try that tonight when I get home. Great input thanks for all your help. The needle tip looked good and I cleaned the bottom of the carb where the high sped jet is, so I think Im ok there. The only thing I didn't do while I was cleaning the carb was to hit it with compressed air.

I'll check the fuel lines first / Replace. I thought about using a clear piece of tube between the fuel pump and carb to see if there are any bubbles too..

Also, does the fuel pump act as a filter too? I know on some Carbs there is a small screen thats right after where the gas comes in that gets dirty and I didn't see one on this carb.

 

[tx1961whaler]

Re: 1973 Johnson 9.5 hp carb rebuild

Yes, replace the fuel lines, all of them if you can afford it. The alcohol in today's fuel really does a number on some old lines....and doesn't seem to affect others. It might have something to do with how much crud there was in the lines before the ethanol broke it loose....