Newbie and Stumped

[Dave in Md]

I'm a newbie to this forum and the new owner of a '53 Cub (...175313J). I picked it up about a month ago and have been working on little repairs in between cleaning 50 years of life off of it. I drove it before I bought it, drove it onto the trailer, and have driven it around the farm as part of a 'wring out' process. It didn't have the power it should have, but was running. It's a solid little machine, no rust, no dents, and no welds.
I decided to rebuild the carb. I've begun to doubt the smarts to that decision because now I can't get the Cub to start. Per the book I seated the adjustment screw then backed it out one turn. After a minute of cranking I had fuel dripping out of the intake of the carb. Thinking something may not be correct inside I pulled it off the tractor, opened it up, checked everything, and installed it back on the tractor. Same results. I leaned the mixture (backed the screw out) and the fuel no longer drips out of the intake after cranking as long as it's out 2 or more turns. At 2 1/2 turns out it'll fire and sometimes run for 1 - 3 seconds before it dies. Any further in or out and I get nothing.
The plugs are clean. I'm getting good spark. Points are at 0.020. And I'm getting constant fuel flow when I pull the line out of the carb (let about a pint run out). I'm stumped. I don't know what else to look for other than a static check on the timing. Any suggestions?
Thanks in advance. (sorry for the long post)
Dave

[Bigdog]

Dave, You probabaly should go ahead and check the timing just to be sure. Proper timing will help offset other mis-adjustments and might make the difference between starting and not starting. It does seem though that you still have a carburetor issue. Re-check the float level and remove and re-clean the main jet to make sure it is open. It should at least start with the idle screw out 1 turn.

[John *.?-!.* cub owner]

Dave, this might be a stupid suggestion (I've made them before), but pull the air hose off while you are cranking it and make sure the choke is opening and not slipping on the shaft, or the lever on the shaft upside down so it is closed when you think it is open. Cubs unless it's extremely cold don't need much choke.

[EZ]

If you have ruled out dirt blocking fuel, a fresh set of plugs would be in order, plus check your timing as Biggy suggests.

You may be getting good fuel flow TO the carb, but maybe your needle has some crud blocking flow to the intake ports.

The carb on these is very touchy as I found, once you get it tuned up proper though they are excellent. I fiddled with one for a couple weeks and it was quite frustrating. You say you have rebuilt the carb? New needle and seat? gaskets? etc........?

[Rudi]

Dave:

First, let me say welcome to the Greatest Forum on the Net and to the Cub Family

Second, might I suggest that you read New Members and Visitors, Please READ. The Cub FAQ's are filled with a lot of really good general knowledge and the Cub Info has some good trouble shooting tips. The Best of H.L. Chauvin puts a humourous yet very helpful tone to fixing your Cub. The Won't Start articles will be really helpful. Also, the Cub Manual Server has lots of info to assist you as well.

You might also want to have a look at Lurker Carl's Cub Carb Fixes on the Manual Server. This is one handy and well written article or should I say a series of great articles that will almost assuredly help you with your carb woes.

As BD, John and EZ already stated, it is probably a fuel problem. Return the main idle screw to the fully seated position. Back it out 1-1/2 turns only. Then adjust the high idle screw by the throttle rod. This may make a difference.

Timing may be an issue but I sort of doubt it especially since you had it running and only played with the carb. Again check the air. Make sure that the manifold gasket is well seated and not leaking/sucking air. Make sure that the upper and lower carb bodies are well mated, the gasket is not pinched and is not sucking air at this point either.

Hmmm, what else?????

I keep coming back to this:

At 2 1/2 turns out it'll fire and sometimes run for 1 - 3 seconds before it dies. Any further in or out and I get nothing.

I ain't no mechanic, but as the guys can tell you I have rebuilt Ellie's carb so many times I can probably do it blindfolded now Don't ask why

This does not make much sense. It keeps pointing to the high idle screw for me. This is the one on the throttle assembly - part #3 is the spring for the screw.



Hope this helps a bit.

Again, Welcome to the Cub Family

[Dave in Md]

Thanks to all for the information. I'll get on it this evening, pull the carb & new plugs just to make sure. Wanted to get at it yesterday but the PC at home has been giving me fits with spyware and adware! If it ain't one thing...
Thanks again, I'll let you know when it's purring again.
Dave

[Yo's Dad]

To really check to see if you are at least getting gas to the inside of the carb, unscrew the drain plug on the bottom of the float chamber. If it doesn't keep running out, then you have a restriction.

[beaconlight]

When I suspect bad carb. I take a spray bottle of gas and shoot a little into the carb with the air filter off. If it starts I shoot a spray in to keep it going. If it does I put my hand over the carb to try to choke it out much stronger than the choke it self will. It worked only once. But it proves that it is carb and not something else.
Bill

[cfrost5]

IM HAVING EXACTLY THE SAME TROUBLE
I REALLY BELIEVE THE FLOAT LEAKS OR THE FLOAT
ARM ISNT PUSHING UP HARD ENOUGH ON THE NEEDLE VALVE
GOING TO CHECK THAT OUT TONIGHT
CARB HAS BEEN REBUILT
WE WILL SEE,,BUT I AGREE THAT IT IS HUGE FRUSTRATING ESPECIALLY
AFTER THE TRACTOR RAN SO GREAT FOR AWHILE..
I EVEN HAD THE LOCAL FARM SUPPLY LOOK AT IT
SAID IT WAS OKAY..
THE FIRST TIME I PUT IT BACK ON, IT RAN FOR 4-5 MINUTES
THEN QUIT AND WONT RESTART
WHO KNOWS.ILL LET YOU KNOW IF I FIGURE IT OUT

[beaconlight]

I hit a bump last summer. And had to run with the choke on to keep running enought to make the garage. I drained the bowl and there was fine rust in it, cleaned the screen in the bowl. Then took the carb off and there was sediment in the bottom of the bowl after that was cleaned I took a fine wire from telephone wire and poked in all the passages and the tube. The idle adjustment screw was out when i did this. Then air was blown through all the passages. Every thing was assembled, the screw reinserted and gently bottomed and backed off 1 1/2 turns. Before the gas line was reinserted all the gas was drained into white plastic buckets. You could not imagine all the brown on the bottom of the buckets. Then the gas was strained through a coffee filter. This cleaned up the gas. (No problem gave up smoking in 1968) Last but not least poured a gallon into the tank and draind it out and filtered it again. this was done several times till it came out clean. of course I had to clean the filter bowl and its screen again. I don't have the screen that is supposed to be on the inlet to the carb so it wasn't touched.
Cub carbs are pure basic stuff. They work well.
After all of that i realize that you seem to have too much fuel. Thats easy too, just get a barbed fitting and plastic hose. remove the plug from the side of the carb replace with the barbed fitting and plastic hose. Hold the hose up and the hight of the gas in the hose corresponds to the level in the carb. There are specs for this but as long as it is at least 1/16" below the gasket and no more than 3/8" they seem to work well. If the gas is higher than the carb, your float or its shut off needle are bad or dirty. Earlier in this thread some one was kind enough to post a carb break down from Rudies files. There is one other possibility, namely that the body of the carb is bent and restricting float movement. Gently, very gently straighten if this is the case.
Yes there are a couple of more exotic problems that could exist but this should get you running. Then if they exist we can all look at them and help you..
Bill

[virg]

I went thru the same process with my cub, gas everywhere and no start. I even tried a new carb with no results. My tractor is magneto equipped and showed plenty of spark on the bench--but I learned that the spark was non-existant when starting the tractor. I replaced the magneto with a rebuilt unit and it cranked on the third revolution. I can now use the hand crank for fun and show-off.

Purchased the magneto while on vacation from JAECKEL BROS PARTS, JEFFERSON, WI. 920-563-3447.

Great folks and a lot of Cub parts.

Dave, if your cub is distributor equipped it still may have the same ignition problem. Please let us know what works.

[beaconlight]

Dave how are you doing? Is your Cub running??
Bill

[Dave in Md]

I have good news... IT'S ALIVE! The re-birth took place yesterday. I worked on the carb in the evenings this past week when I could find time. I discovered that the float limits were wrong and the top half of the carb was slightly distorted. To be on the safe side, I followed the suggestion to make sure it was clean. Once again it was torn down and compressed air & carb cleaner were blown thru all of the ports. Before mating the halves as the last step to getting this done I got to thinking about the articles that were suggested for reading (Lurker Carl's I believe). Especially that one about the gaskets that come in the kits. I had used a small screw driver thru the drain hole to see if the float was able to move freely before I began the tear-down. Just for grins and giggles I decided to trim the gasket as shown in the article. When the carb was back together I checked the ease of travel on the float again. It moved easier! I reassembled everything. Then double checked that I hadn't missed anything, pulled the ignition switch, set the choke at about half way, and hit the starter. It cranked. Deep breath. Pulled the starter again and she came to life!
Thanks to everyone for their responses and suggestions. You helped me to correct something myself when I was almost at the point of grabbing the telephone and my check book.
Dave

[beaconlight]

Congrats.

Bill

[Rudi]

Dave:

Congratulations

Amazing isn't it, that feeling you get when you have fixed something yourself. I have been fixing things for nigh on 45 years or so, ever since I was a wee tyke and started breaking things and I still get that feeling every time I fix something.

I will say though, there is nothing like the feeling you get when you fix your Cub, that is in it's own special category

We knew you could do it. Along with assistance from the wonderful articles the guys have contributed along with the excellent advice that is available on this forum, I don't think there is much that you will find you cannot fix.

Post some pics.....

Again, Congrats