Thu Sep 09, 2004 1:34 pm
I have a 56 cub that I have worked on for some time now. I have read all the post about carbs and tuning them up. I have been reading these post here and on atis for about 6 years and I do lots of automotive work so I am no dummy to engines.
I have rebuilt the carb and checked out things from Carl lurkers web page and it seems my tractor still sumbles when running. the govenor will surge once in a while and the exhaust sounds like it sputters and not smooth. I tired the carb off my 48 cub that sounds great never has a problem. It seemed like it ran some what better but not great.
maybe I am hearing the difference in the up right exhaust to the 56 cubs under slung exhaust.
the 48 cub takes off like a rocket in third gear but the 56 has a hard time. maybe becasue it has loaded tires?
I have checked the plugs and cap and rotor. I think I will change the spark plug wires.
any ideas short of buying all new points, plugs, cap and rotor?
the govenor surges sometimes when I idle down for stopping what causes this? and it seems to me that when I rev it up it is almost sputtering through the exhasut. Do you think it is out of time?
some reason I am not getting good power in third gear.
it was rebuilt before I bought about 1 year before and the man passed away he son told me it was rebuilt the year before.
my 48 has never been rebuilt and will run circles around it.
I am going to start over guys but where should I start?
Thu Sep 09, 2004 2:35 pm
Chad, have you thought about checking and adjusting the valves?
Thu Sep 09, 2004 2:59 pm
The extra weight of fluid in the tires will sap some power, but it won't cause the sputtering and surging. Although the PO says the engine was rebuilt, don't assume what the mechanic did to the engine what you would have done to call it 'rebuilt'. Rule out the routine gremlins and do a complete tune up. This gives you a solid foundation to troubleshoot from if the tune up doesn't fix the problem. Since you'll be fooling with them anyhow, replace the plugs, points, cap, etc with new. Replace the plug wires with solid copper core instead of the automotive style designed to supress radio static. Check the compression readings for each cylinder. Reset the clearance for all the valves since tight valves will cause the symptoms you describe.
You've already given the fuel system a good cleaning and I'm sure you set the governor linkage to spec. Check the play in the linkage between the throttle to the governor. A little wear at each joint will add up to a lot of play at the carburetor and give the impression of no power since the carburetor can't respond instantly to the governor with slack in the linkage. It's hard to get to but look closely at the governor spring, it should be a tight coil without gaps and not loose from worn hooks or holes. The governor weights may be sticking and not responding to power demand.
Good luck, hope the problem is an easy fix.
Thu Sep 09, 2004 4:35 pm
Chad. I'm thinking like Bigdog. Colud be carbon buildup on your valves. Check your compression. Build up may be causing leakage around your valves and therefore, your losing power. Sounds like you have the fuel and timing down ok.........
Thu Sep 09, 2004 4:36 pm
To solve the surging - pages 2-18 thru 2-21 in the GSS-1411 Blue Ribbon Service manual outlines how to make all the governor adjustments.
Fri Sep 10, 2004 6:06 am
I will look at the valves have not done those on a cub yet. I wanted to on the old 48 but it runs good so I wont mess with it.
I will assume that the engine was rebuilt properly just becasue I was told that the son-in-law of the PO was a auto mechanic by trade and I would hope that he would do it right.
Maybe the valves like you said I have been thinking about that but didn't want to have to do it.
I think I will do a complete tune up also it may not need it but then I will know it is right and what exactly has been done.
I will try to work on part of it this weekend and report back but it may be a few weeks before I get the time to really look into it. Oh I have also set the govenor linkage to spec and played with it several different times to stop some of the surging.
Fri Sep 10, 2004 7:29 am
my 55 did the same last year I also thought fuel & work the carb over for 4 days it turn out to be a spark plug I never check them cause they were only 2 week old
finally got the helper rod thanks again
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