Carborator help 1958 (1951??) cub Lo Boy

Tue Nov 20, 2012 9:48 pm

Hi all,

On Saturday I purchased a 1958 Lo Boy and a 1951 standard Farmall Cub tractors. These were in a far away land (SeaTac, WA) and he listed the Lo Boy as in running condition. Well, when he called to deliver, he said he couldn't get it started, but only that day he could deliver. Yes, my wife keeps me away from bridges in Brooklyn. He said it seems to be flooding. He also said he swapped the engine from the 51 HiBoy to the 58 LoBoy, but he said run fine in September.

It turns over, has spark, but gas pours out of the drain in the bottom of the throttle body portion of the carb. I have had it apart 7 times (lucky 7??), have soaked the carb, cleaned all ports and passages, installed new needle and seat, new bowl and manifold gasket, adjusted float to 1.4 /1.6 inches. The needle seats when tested, float does not leak and moves freely after assembly. NOW WHAT??? Only marks on the carb is the IH symbol.

HELP!!! Thanks!!!
Tony in wind and rain swept northwest Washington state

Re: Carborator help 1958 (1951??) cub Lo Boy

Tue Nov 20, 2012 10:07 pm

You may have a boatload of crud between the sediment bowl and carb.

Open the fuel line at the carb and run a quart or so of gas through a white coffee filter and see what is getting to the carb.

Since this cub is new to you for all you know the sediment bowl screen could be missing.

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 5:45 am

check the timing.

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 6:17 am

You should clean the sediment bowl and be sure there is a screen in it .
For some reason the float may work while you are checking it off the tractor but when you put it back on the tractor it must be rubbing or the needle is not shutting the flow off. Either from getting trash in it or worn out.
Have you put a kit in the carb.
Be sure and do the float measurements with the gasket on.

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 9:22 am

Start at the beginning with a 100% engine tune up. Conduct compression tests. Move on to ignition timing. Lastly the carburetion issue.
but he said run fine in September.
Sounds like a statement a politician would make. September in which year.

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 10:13 am

Have you tried to pull start it?

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 10:45 am

WELCOME TO THE FORUM! Good luck getting it running.....I'm sure it's something simple

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 4:33 pm

Here comes the bad news, maybe. During the 1953 model year, some engine improvements were introduced for the Cub. The changes did boost power slightly but probably were intended more to extend engine life, especially under heavy use. If the owner put the 1951 engine in the 1958 LoBoy, that was not an improvement to the tractor. And it raises questions about the engine presently in the 1951 tractor. Is it the 1958 engine which has since been repaired/rebuilt? Simply swapping the engines between tractors without doing other things accomplishes nothing but busy work. So why the engine swap?

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 9:20 pm

I have both tractors, taking the previous owner's word. The 51 is now a parts machine, the engine has been cannibalized, I assume that the engine in the 58 was shot. I have tried compression on the 58, 95-100# all four cylinders, good blue spark. I even tried spraying WD40 into the carb intake with fuel drained, not even a burp. What should I try next?
Thanks
Tony

Re: Carborator help 1958 (1951??) cub Lo Boy

Wed Nov 21, 2012 9:32 pm

tonystoy wrote:Compression 95-100# all four cylinders, good blue spark. What should I try next?
Time ignition to engine.
Eugene wrote:Start at the beginning with a 100% engine tune up. Conduct compression tests. Move on to ignition timing. Lastly the carburetion issue.

Re: Carborator help 1958 (1951??) cub Lo Boy

Thu Nov 22, 2012 8:27 am

Where are you getting the blue spark at ?
If your checking it at any place but the spark plugs, put new plugs in it.
Make sure the plug wires are in the correct firing order.
Check ignition timing.
Check valve adjustment.
Make sure intake manifold is tight.

tonystoy wrote:It turns over, has spark, but gas pours out of the drain in the bottom of the throttle body portion of the carb. I have had it apart 7 times (lucky 7??), have soaked the carb, cleaned all ports and passages, installed new needle and seat, new bowl and manifold gasket, adjusted float to 1.4 /1.6 inches. The needle seats when tested, float does not leak and moves freely after assembly. NOW WHAT??? Only marks on the carb is the IH symbol.


Is the fuel leaking with the fuel on only, or while trying to start it ? If it is with fuel on only, you have a needle and seat or float problem. If it only leaks trying to start it, it is fuel that is not drawn in to the cylinders and drains back into the carb because of the updraft design. The amount of fuel depends on how long you crank it.