Carb tuning on 1967 johnson 6hp (CD-24D)

[Nailknot85]

Hello everyone newby to the site here. I have a few questions about carb tuning on an old johnson 6 horse outboard, model CD-24D, not sure on carb specifics at the moment though since I am away from home, is there more than one carb available for these motors?

TL;DR: I need base settings for a carb with the low speed needle/seat removed.

I decided it would be a good idea to take the old girl apart for some winter maintenance last winter, last time I took 'er out it took a lot of grunting to get a start, pretty good though for having sat in the back of a shed for two years.

My carb only has a high speed needle, the low speed needle and seat are blocked off with a bolt, this is confounding me as far as base settings go because the maintenance manual I have gives base settings for high speed and low speed needles.

I made the mistake of not recording the current needle settings on tear down and low and behold using the base settings in the manual result in no startey startey. At first I thought it was a fuel pump problem but after moving the diaphragm spring to the proper position I get fuel squirting out of its outlet pretty reliably.

The only way I have been able to get the motor to run is by completely removing the mixture needle leaving a gaping hole in its place, this has resulted in a running motor for anywhere between 1 and 5 minutes, after that it slowly bogs down and dies.

I will admit that I haven't devoted that much time to it since being disappointed 6 months ago, this and the leaky LU I caused kind of let the wind out of my sails.

Anyhow thanks for reading, hopefully there's an old guru out there who can help me sort this out.

 

[Daviet]

Re: Carb tuning on 1967 johnson 6hp (CD-24D)

I think you are confused on the low speed needle.
Your carb has a fixed orifice as a high speed jet, located behind the bowel drain screw, #'s 15 and 43.
The low speed needle is located at the top of the carb # 37.
The static setting for the low speed needle is 1 1/4 turn out from lightly seated, then you have to fine tune it with the boat in the water and the engine in gear.
The below picture is for a 1968, but the carb is the same.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[kfa4303]

Re: Carb tuning on 1967 johnson 6hp (CD-24D)

Hi Nail. Welcome to iboats. Here are some handy links to help you get the carb dialed in. The first will explain the basic needles settings for the various types of OMC carbs and the second will show you how to rebuild a vintage OMC carb. It's for a different model, but all the basic steps are the same. You can get a carb kit and any other routine parts you may need right here at iboats for about $20 each. The third link is a great all around maintenance site and the final link is a parts catalog for your motor with exploded diagrams. Holler if you get stuck.

http://forums.iboats.com/showthread.php?t=167352

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

http://www.leeroysramblings.com/OMC_6hp.htm

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/382085/38208500001.htm

 

[Nailknot85]

Re: Carb tuning on 1967 johnson 6hp (CD-24D)

Wow thanks for the quick replies guys. I was confused on which jet was which wasn't I, excellent now I have somewhere to start.

I should also add that other than new plugs I did nothing to the ignition system during this overhaul, by nothing I mean I didn't even remember to check the points gap while I had the fly wheel off, all I did was clean them up with some sand paper. The points, condensors and coils are all quite new looking and setting the timing wasn't something I wanted to do. The timing advance cam and follower did seem to have a lot of lost motion when turning the throttle twist grip but it seems there is no adjustment for this?


Thanks again for your help, this site is awesome.

 

[kfa4303]

Re: Carb tuning on 1967 johnson 6hp (CD-24D)

Here's a great ignition link, if you need it. Well worth the cost and effort to rebuild it. You can get all the components you need (coils, tuen up kit, carb kit, etc...) right here at iboats for about $20 each. You don't really set the timing on these old motors, that's done by proper alignment of the flywheel on to the crankshaft using the woodruff key as a guide. It's not uncommon for there to be some, quite a bit, of slop in the armature plate. Do a search here in the forums for how to fix it, should it become an issue. Good luck. Holler if you get stuck again.

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm