Stumped with Cub Lowboy

Posted by Jeff Killin on April 27, 2002 at 16:48:32 from (65.133.230.16):

I can't think of anything else to try and could really use some advise......

I've owned a 1966 Cub Lowboy (yellow/white) for 7 years and up until this spring it's run just great. It has a Woods belly mower which does a fine job cutting my 3 acres. Had some major work done over the winter (replace rear engine oil seal, new radiator couple of other items) so she'd be ready to go this spring. 1st time cutting, after an hour of running great, my problem developed.

The problem - All of a sudden she lost power, acted as if it was hitting on two cylinders, finally stalled out. Could only re-start her if the throttle was way back, and as soon as I'd give her more gas it would die. After a lot of trouble shooting and replacing suspected parts (see below) I determined that if the choke was pulled out so the choke plate restricted the carb air intake by approx. 75% she ran ok. I finished cutting the grass but she didn't seem to have as much power.

Since the choke restricts the air intake, I thought, for some reason she must not be getting enough fuel, so I rebuilt the carbarator, and flushed out the fuel line and tank from head to toe. No luck – She runs/sounds good (suspect low power though) but only if the choke plate is 75% closed. If I open the choke plate even slightly she starts sputtering and coughing. Take out all the choke (air intake full open) and she stalls. So I'm left with carefully positioning the choke plate till she sounds/runs good. At idle I can open the air intake and it will run, but barely, give her just a bit of gas and she dies.

I can't figure out what is causing the problem and what to try next!

If anyone has experienced this, or knows what could be going wrong I'd be gratefull if you could pass on advise. I'm at my wits end and just can't believe that the best thing to do is continue to run her by restricting the air intake by carefully setting the choke.

I've listed below everything I've done already.

Electrical
New coil, condenser, plugs & wires
Points & gap replaced last fall and look ok.

Fuel - IH carborator
Re-build kit, new main gasket between two halves, fuel valve and seat. main fuel jet is clean/clear. Carb completely clean. No air leaks around top/bottom sealing gasket or gasket at intake manifold. Fuel line is new, no filter on line, and fuel flows freely from gas tank to carb. Gas tank cleaned, fuel cock cleaned, and tank is vented ok.

Air
Air cleaner & pathway is clear (oil bath type) and air cleaner intake pipe has good suction when running

Possibilities??
timing? Had her re-timed at the shop and she ran great for an hour. Could timing have slipped??

carb. float?? looked ok when rebuilt carb

Thanks for listening and any help appreciated.

Jeff Killin

Follow Ups:

• Re: Stumped with Cub Lowboy Andy Martin 14:15:26 04/28/02 (1)
  • Re: Re: Stumped with Cub Lowboy Jeff Killin 18:04:05 05/02/02 (0)
• Re: Stumped with Cub Lowboy ltf in nc 07:46:50 04/28/02 (0)
• Re: Stumped with Cub Lowboy Todd Wilson 22:21:52 04/27/02 (0)
• Re: Stumped with Cub Lowboy Dale 20:13:38 04/27/02 (0)
• Re: Stumped with Cub Lowboy BIG JOHN 18:27:05 04/27/02 (0)
• Re: Stumped with Cub Lowboy Jon D 18:20:44 04/27/02 (0)

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