2N Carb

Hi All,

I've been trying to diagnose a problem with my carb. My manual says when adjusting the idle-mix, at an idle, to turn the screw inward till the engine falters then turn it out till it runs smoothly. On mine I can turn it in all the way and the engine won't falter a bit.

Thus I decided to take it apart, clean and put in a carb kit. With it apart I noticed a couple things.

1. The brass idle jet is very boogered up. I guess the previous owner tried removing it and just made a mess. Would this cause the carb to malfunction? I wonder if any brass pieces getting behind the jet might mess things up.
With this in mind should I go ahead and try to remove it and do you have suggestions on doing this? I'm guessing I need to very very carefully drill it out but any other ideas might be good to try. Would using wd40 help unscrew it?


2. The choke and throttle shafts seem to have a bit of play. Should I be putting in bushings?


Thanks!

I would leave the jet alone and replace the throttle bushing.

The idle adjustment is an air adjustment. You are probably sucking air in around the throttle shaft. I don't think the choke shaft would make any difference!

You need to rebuild that carb or have it rebuilt.

I've rebuilt N carbs, A model carbs, lawn mower carbs,,,,,,etc, etc. But I don't rebuild N carbs anymore because there is a local shop that does great work at a very reasonable price. I just have carbs rebuilt by:

Automotive Manufacturers Inc
2400 N Lombardy St Richmond, VA 23220
(804) 321-6861

They do mail order work. And they also rebuild clutches, pressure plates, water pumps, alternators, generators, starters & reline brakes.

By the time you buy a complete carb kit & the cleaning solvent, the $80 they charge for a rebuild is worth it.

GB in MT ( a regular here) also does great work on N carbs. But, I don't think his shop is open yet.

To answer your questions:

" Would this cause the carb to malfunction?" Yes

" I wonder if any brass pieces getting behind the jet might mess things up." Possibly

" With this in mind should I go ahead and try to remove it and do you have suggestions on doing this? " Just be careful.

" I'm guessing I need to very very carefully drill it " Good luck w/ that. I wouldn't try it, but that's because I'm ham-handed.

" Would using wd40 help unscrew it?" No. It's not a penetrating oil. Try PB Blaster.

" Should I be putting in bushings?" Without a doubt.
75 Tips

(quoted from post at 15:08:49 04/17/14) Hi All,

I've been trying to diagnose a problem with my carb. My manual says when adjusting the idle-mix, at an idle, to turn the screw inward till the engine falters then turn it out till it runs smoothly. On mine I can turn it in all the way and the engine won't falter a bit.

Thus I decided to take it apart, clean and put in a carb kit. With it apart I noticed a couple things.

1. The brass idle jet is very boogered up. I guess the previous owner tried removing it and just made a mess. Would this cause the carb to malfunction? I wonder if any brass pieces getting behind the jet might mess things up.
With this in mind should I go ahead and try to remove it and do you have suggestions on doing this? I'm guessing I need to very very carefully drill it out but any other ideas might be good to try. Would using wd40 help unscrew it?


2. The choke and throttle shafts seem to have a bit of play. Should I be putting in bushings?


Thanks!

Click to expand...

our engine speed needs to be very, very slow (400 to 500 rpm) or else the idle adjust is pretty much out of the picture. Air leak at throttle shaft could be your problem. Although many & some very thorough & reputable people 'must' get those jets out, I recommend against it for the average fellow. Usually destroy the carb trying! If you can blow air both ways through the jet & through the idle & transfer ports in throat to & from the idle jet & or idle adjust screw hole, it is likely clear.

Many thanks to all of you.

One other thing I noticed the carb has some powdery residue in it. I'm guessing it's caused by ethanol in the gas. Any suggestions for an additive to deal with the ethanol?

Marine Sta-Bil.

Every drop of gas that comes on the place in cans gets it.
75 Tips

Not that there is anything wrong with sta bil, never tried it, but I use Seafoam- never had any problems

You might try a left handed drill to get those jets out. I've had good luck using them, start small and work your way up. You can pick up an inexpensive set at Harbor Freight if you don't have any.

SEAFOAM (tm).....stuff works good in 4 hsp. boat engines, too. Don't wanna to stall "down river".

OK to stall "upriver".

John,PA 3 sheets to the wind. Meaning "got her moving, now."

I will try some in my Johnson 4 hsp outboard.

could he spray some starting fluid/carb cleaner around that spot to see if it is sucking in air there? would change idle speed if it is doing so?

lee