Fuel - carb problem

The Cub Club -- Questions and answers to all of your Cub related issues.
Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
Jim Becker
Team Cub
Team Cub
Posts: 16074
Joined: Sun Feb 02, 2003 2:59 pm
Zip Code: 55319
Circle of Safety: Y
Location: MN

Re: Fuel - carb problem

Postby Jim Becker » Fri May 10, 2019 9:06 pm

Dan Stuckey wrote:
Jim Becker wrote:. . . Have you checked the quality of the ignition spark when it acts up? . . .

. . . Listen to all the suggestions here but would a weak spark cause this problem like immediately turning from downhill to going uphill? . . .

Voltage required to jump a gap increases with the air pressure at the gap. Turn from downhill to uphill, the governor opens the throttle and more air/fuel mixture is drawn into the cylinder. Increased cylinder charge results in more compression pressure thus more voltage requirement.

cubbrian
10+ Years
10+ Years
Posts: 891
Joined: Sun Apr 08, 2007 7:47 pm
Zip Code: 47631
Tractors Owned: 1955 Cub w/9 different 1 point implements
1948 Cub
1948 McCormick W-6
1949 H
1949 M
1961 560 w/ 412 fast hitch plow
1966 140
1973 666
Allis Chalmers C w/sickle mower
Case 400
Economy 14 hp tractor
Location: IN, New Harmony

Re: Fuel - carb problem

Postby cubbrian » Fri May 10, 2019 9:32 pm

Could the governor weights sticking cause this problem? Seems like it would happen on level ground as well though.

Dan Stuckey
10+ Years
10+ Years
Posts: 174
Joined: Thu Jul 08, 2004 6:00 pm

Re: Fuel - carb problem

Postby Dan Stuckey » Mon May 13, 2019 5:58 am

Jim Becker wrote:
Dan Stuckey wrote:
Jim Becker wrote:. . . Have you checked the quality of the ignition spark when it acts up? . . .

. . . Listen to all the suggestions here but would a weak spark cause this problem like immediately turning from downhill to going uphill? . . .

Voltage required to jump a gap increases with the air pressure at the gap. Turn from downhill to uphill, the governor opens the throttle and more air/fuel mixture is drawn into the cylinder. Increased cylinder charge results in more compression pressure thus more voltage requirement.


Will certainly dig that way if my carb cleaning fails to produce results. Got the carb apart yesterday and flushed it all out. Anxious to ck results later in the week, if this rain ever stops.

Dan Stuckey
10+ Years
10+ Years
Posts: 174
Joined: Thu Jul 08, 2004 6:00 pm

Re: Fuel - carb problem

Postby Dan Stuckey » Mon May 13, 2019 6:02 pm

UPDATE on my Cub.
Certainly wanted to post my results of my Cub. Well over the weekend I took the carb apart and went over it all with just carb cleaner, checking inlet screen real well and reassembling. Today I got back to the Cub and put it back together. Gave it a good workout in high wet grass for about a hours and it never missed a beat. Was raining out but really wanted to give it a test. As I said in my initial post, I put on a new shut off and screen just last year and my tank is in pretty good shape so I thought about this as I mowed. I so a lot of small engine repairs and have seen first hand just what ethanol fuel can do to rubber fuel lines inside. So I had some 5/16'' fuel line that I cut and replaced the old line which was probably 6-8 years old. Thought perhaps a bit of the old line might have been what caused my problem.

Felt pretty good as I went some through some muddy grass without getting stuck. Last fall my old rims and turf tires went south so I replaced with new rims, new ag tires and found my some wheel weights. I can now go through mud without the scary feeling of getting stuck and thinking, why did I have to go through mud. Ha And half a dozen years ago my rear main seal was leaking bad and I happened onto a rebuilt engine on this forum that was out of a numbered Cub and since I had to split this thing I thought might as well update my engine and double the hp. Really helps with the big mower deck. Just had to pull the crank out of the numbered Cub engine to have it drill for a pilot bearing to have this engine fit my '49.

Thanks guys for the hints and suggestions to my problem. Runnin Hard!!

Waif
5+ Years
5+ Years
Posts: 1025
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Fuel - carb problem

Postby Waif » Tue May 14, 2019 12:49 pm

That's good to read.

Your mention of that cruddy evil ethanol garbage brings to mind the carbs air cleaner hose/hoses depending on model.

Looking at a tired out carb air intake hose on one of the tractors.
That could cause problems as hose breaks down....
Too , the hose has to be able to tolerate oil and gas as well compared to a radiator hose type.
The wrong hose , or a weathered one could be feeding debris into the carb on yours once in a while.

Dan Stuckey
10+ Years
10+ Years
Posts: 174
Joined: Thu Jul 08, 2004 6:00 pm

Re: Fuel - carb problem

Postby Dan Stuckey » Tue May 14, 2019 3:06 pm

Waif wrote:That's good to read.

Your mention of that cruddy evil ethanol garbage brings to mind the carbs air cleaner hose/hoses depending on model.

Looking at a tired out carb air intake hose on one of the tractors.
That could cause problems as hose breaks down....
Too , the hose has to be able to tolerate oil and gas as well compared to a radiator hose type.
The wrong hose , or a weathered one could be feeding debris into the carb on yours once in a while.


Regarding cruddy ethanol fuel, I have worked on several mowers or blowers that were not getting any fuel from the fuel tank to the carb. My discovery was that the layers of the gas fuel line had delaminated and collapsed, stopping all fuel flow. Ethanol sucks.

Waif
5+ Years
5+ Years
Posts: 1025
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Fuel - carb problem

Postby Waif » Tue May 14, 2019 4:49 pm

Dan Stuckey wrote:
Waif wrote:That's good to read.

Your mention of that cruddy evil ethanol garbage brings to mind the carbs air cleaner hose/hoses depending on model.

Looking at a tired out carb air intake hose on one of the tractors.
That could cause problems as hose breaks down....
Too , the hose has to be able to tolerate oil and gas as well compared to a radiator hose type.
The wrong hose , or a weathered one could be feeding debris into the carb on yours once in a while.


Regarding cruddy ethanol fuel, I have worked on several mowers or blowers that were not getting any fuel from the fuel tank to the carb. My discovery was that the layers of the gas fuel line had delaminated and collapsed, stopping all fuel flow. Ethanol sucks.


Yes ethanol does suck. We have come a long was from low compression white gas. Additives to reach octane with less octane being used are bad enough without adding ethanol....

Added fuel treatment (with ethanol being the reason the type treatment was used) with the fuel for an outboard motor and ended up with a bad line eventually anyways.
Soft , then mushy like it was melting , then failed. Have had a hose kink before too when it weakened.

Small engines really suffer fast. Not only old style fuel lines , but carbs too if fuel is left in them.

Recently found a rec fuel source closer to home , so will be using more of it.


  • Similar Topics
    Replies
    Views
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: inairam, Nautiluscont, raystractors and 3 guests