OC3 fouls plugs

tired iron · September 22, 2010, 03:42:37 AM

I have a 1956 oc3 industrial model, it goes through a alot of plugs. I really want to be able to start this thing up with out replacing the plugs every time. First off, do I have the correct plugs, NGK B-4? secondly, I don't really know what causes fouling. It ran fine 3 days ago, today I went to start it and it pops 2 or 3 times and then the engine just spins and poofs out smoke until I stop cranking. When I start cranking again, it fires a couple and then nothing. I can repeat this process indefinately until the battery is dead. I was told to run the carb dry when I intend to leave it sit awhile, so i turn off the fuel and let it idle out. Is that a good idea, It seems like when i do that it won't run the next time. Also I rarely work it hard, I has no blade so i just drive it around and cruize through the woods, sometimes drag a few logs around. I love the old tractors but it's not fun to fix it more than drive it. I know you guys can help me get this thing right.

TDLMOMOWERS · September 22, 2010, 12:18:37 PM

I personally don't like to run a carb. out of gas. You might try using a gasoline stabilizer, like Stabil. I run it all year long in all my outdoor power equipment. I mix it at 2oz. to 5gal of gas. You may try running a hotter heat range on the plugs to help with the fouling problem. Make sure you have the right plugs for your engine first, then you could step up a heat range and try them. Fouling can have several causes, such as worn piston rings or worn valve guides or valve seals. It would be a good idea to do a compression check and see if the rings are worn. Also make sure that your ignition system is in good working order. I don't know if you have a magneto or a battery ignition system on that engine. If you have a battery ignition, check to be sure you are getting good voltage to the coil and distributer. Do you have a coil with built in resistance, or are you using an external ballast resister?

hotratz · September 22, 2010, 01:04:57 PM

Are the plugs oil fouled or fuel fouled?

440roadrunner · September 22, 2010, 06:08:42 PM

Quote from: "TDLMOMOWERS"I personally don't like to run a carb. out of gas.

I'd like to hear your thoughts "why." I do that all the time.

The rest of the two poster's comments are right on

1. Determine correct plugs.

2. Are plugs oil fouled or fuel fouled?

3. Run a compression check to be sure

4. Check ignition, make sure you actually have a good hot spark

5. How old/ fresh is the fuel you are using? If any doubt, drain and replace

Some carbs are "fussy" about mechanical limits on float. Might be a possibility that the float is sticking closed, or more probably open due to running it out of gas, then won't "float up." this is not a fault of running it dry, it's either gum in the carb, or a float pivot that is worn, or a mechanical stop on the float allowing it to go "too far" and jam.

One thing you might try "next time" is to NOT turn ON the fuel but rather prime with a squirt can and see if it fires right off.

Also, are the plugs tending to foul AFTER SHUTOFF or at the next startup attempt?

tired iron · September 22, 2010, 11:57:53 PM

I do have a mag ignition. I didn't ever want to think about having to re build the mag, I had heard it was expensive.
I haven't ever tested the compression, I'd assumed it was good because it never smokes at all. I'll swipe a compression gauge from somebody.
I just found the engine numbers, 94373TC- IXB3 Does that tell anybody what plugs i should have? I just got the ones Napa said were for this machine.
the engine was replaced sometime in history and not repainted to match, it's primer brown- possibly a rebuild. I can't say if the plugs are oil or fuel fouled, They are always soaked with gas when I get them out. A couple times I was able to torch them clean and stick them back in and they worked for a while longer. they never are in long enough to get very crusty. How would I know when they foul- just pull them before I try starting it?

TDLMOMOWERS · September 23, 2010, 12:24:40 AM

I guess there are different opinions on whether to run an engine out of gas or leave gas in the carb. I have worked on small engines for 20+ years and have found to my own personal opinion that I have better luck with seasonal storage if I leave gas in the tanks and carbs. I always run Stabil all year long so maybe that makes a difference. For extended storage, like several years, yes you would be better off draining the system. Some fuel, if drained out of the carb. leaves a dry residue in the float bowl as the fuel drys up. I don't like to see the diaphrams get dry and shrink up on some small engines with diaphram carbs. Right now I have an engine on the bench that had fuel in the tank for 8+ years, and it is a mess, so yes ,sometimes it is great to run the engine dry.

440roadrunner · September 23, 2010, 01:44:23 AM

Quote from: "tired iron"I can't say if the plugs are oil or fuel fouled, They are always soaked with gas when I get them out. ?

Oil fouled, running too rich, or gas soaked, I'd guess is the question you have

Oil fouled is usually very evident, sort of slimy, oily, black

Running too rich (when running for a period of time, and warmed) is black, dry, sooty

gas soaked is just that, and if that is your problem, rather than the top two, is almost always a serious carb problem, IE flooding, float level too high and dripping raw fuel over the top of the "siphon" or way way too much choke

You might start by disconnecting the air filter connection--maybe it's plugged

If you turn on the fuel valve and do nothing, does the carb drip raw gas?

tired iron · September 23, 2010, 05:00:05 AM

Sorry, I can't figure out the quotes thing yet.
The fuel used to leak a bit at the sediment bowl, thats why I made a habit to shut off the fuel when parked. It also drips out the intake if it doesn't fire right up. I haven't noticed it leaking from the carb while parked but it think I am going to leave the fuel on for a while and see what happens. Anyways, I think I should pop that carb open and see what's happening in there- check the float and the action. I can't remember if I've gone through it before- maybe 3 years ago. At this point I definately have a gas soaked plug problem but that is always after much cranking. It feels like it will start on the next try because it fires a few but then dies. It will continue to do tis untill the battery is dead, then I pull the plugs and they're soaked. I know I need to pull the plugs as soon as it won't start to get an accurate story. Does anybody have a suggestion on what plugs should be in this engine? I do need new plugs to move on with my testing. I had NGK B-4 plugs. I thought NGK were good plugs, maybe not.

hotratz · September 23, 2010, 01:17:15 PM

If you do a search for "Spark Plugs " there are several entries with part numbers. I'm thinking your spark plugs are not your issue at this point. You said it ran fine a few days ago? Test the plugs you have to see if they give you a good strong blue spark outside of the cylinder. I'm thinking it might be time to put a kit in your carb. I'd pull it apart and soak it in a coffee can with acetone in it for a couple days, clean it out, blow out all the orifices with air, put the kit in it and set it up with the directions in the kit.

440roadrunner · September 23, 2010, 06:56:04 PM

This is starting to sound like a carb/ dirt problem. Don't forget to check for free easy action of the float pivots, and the float itself. Make sure if it's brass it isn't full of fuel (leak) or if it's a non-metallic float, that it actually does float ("waterlogged")

tired iron · September 29, 2010, 09:54:51 PM

I don't have a fouled plugs problem anymore, it has become a no spark problem. It only sends a spark during initial cranking then only number 2 fires. I had all four plugs wired up laying on the tracks. have the mag out now looking for trouble. don't have much knowledge of mags. it's a FM X- B19B Not an oliver original but I think it is the same. I'm having a hard time reading the computer keys, there seems to be some sort of grease on them.

Robert Barbour · September 30, 2010, 01:45:00 AM

Under the cap of the mag you should find a set of points and a condensor just like a distributor with a coil. Change the condensor and clean the points or get new ones if you can find some. Set points to .018". and give a a try.

tired iron · September 30, 2010, 04:12:40 AM

I got a new condenser, the one listed in the book was $18, I and the parts guy thought that was excessive so he gave me a $3 one that works great. I baked the main assembly of the mag for about 3 hours at 200 degrees (before the wife got home). I was amazed after about 10 minutes to see all the water cooking off that thing. Then i filed the points to my liking, slammed it all back together and it started right up even though I mixed up the plug wired. It was too dark to see anything so I'll fix the wires tomorrow. And I'll return the new plugs I didn't use.

440roadrunner · September 30, 2010, 05:33:54 AM

I you actually saw water/ vapor/ steam "baking" out of the coil you probably have not fixed it. Frankly you might try to build a vacuum tank and warm it up good, then pull a deep vacuum on it just like an HVAC/ refer system. Water will boil off at a low temp and "pull out" of the coil.

"Build a tank?" Around here there's lots of old pressure cookers lying about for a few bucks. Plug up the blow off and the rubber "blow out plug" and if it has a good gasket you should be set. There's all kinds of ways you can do that.

Points condenser are a good bet. Points tend to corrode without use, and depending on the age of the condenser, it may be bad. Condensers weren't very good in the "old days, say, pre WWII and maybe up to about '60 or so. Then you could get some good quality say, up into the '80's or so, before everybody discovered China.

tired iron · October 01, 2010, 01:20:39 AM

Quote from: "440roadrunner"I you actually saw water/ vapor/ steam "baking" out of the coil you probably have not fixed it. Frankly you might try to build a vacuum tank and warm it up good, then pull a deep vacuum on it just like an HVAC/ refer system. Water will boil off at a low temp and "pull out" of the coil.

I don't understand what you mean about baking it out. I saw heavy condensation forming all over the top on the mag on the alloy part. It all baked away, now I have consistant sparks. However, it isn't fixed anyway.

I can't get a good firing order. Everything fires good and hot and consistantly. It seems like it's not in time. either 1 and 4 don't hit or two and 3 don't hit. they all have a good spark and the plugs fire fine out of the engine. The engine runs but doesn't run smooth. I can pull the wires off one by one and find that 1and 4 aren't helping. I tried tuning the mag driver back half a turn and then it only backfired hard with no running. When i put it back, it ran poorly again but now 2and 3 don't fire. I think the wires are right, they've been labeled for a few years and always work fine. I am going out for new wires right away but usually when wires are bad they dont switch places.

I am wondering if when I put the points and condencer back if I got something screwed up. I lined up the dot with 'C' on the fiber gear.
I screwed something up, please help me.