Strange knocking noise

[Mahoman]

Thank you everyone I’ll look into these suggestions I gotta use this tractor for this year but this winter it’s coming apart for The. Last. Time. I already had to re spit it because the rear main was spinning with the crankshaft. Every day I’m thinking I should’ve just got a good running cub to begin with. Also my 2nd gear has a tooth missing and makes a hell of a noise if i use it so I’ll be doing a gear replacement as well.

[Mahoman]

The gas cap seems to leak gas out onto the hood, that isn't very safe to use it that way.
If the surface where the gas cap gasket fits on the gas tank is good, and the gas cap gasket is old and hard, the gasket probably needs replacing.
TM Tractor has a new gasket for the original style gas caps, below is the listing.

http://www.tmtractor.com/new/fl/785fp.htm

They also have a free replacement gas cap, it looks different than the original. You can read about it.

http://www.tmtractor.com/new/fl/fuelcap.htm

They won't seal well if the surface on the gas tank is bent.

I sent you a PM.

I sent in my request for a free one about 8 months ago I only put 5 gallons in at a time it never gets past an inch or two away from the cap

[Mahoman]

is the fan good, has oil in it, not all worn out

yep, I redid the fan myself put new oil in, it did have a little play but not much fan is not bent it looks pretty good

[Mahoman]

That is odd, mine sounds kinda like that under really heavy load like up hill cultivating in second gear but it's definitely not a knock in my case just normal engine noise and it dosen't stick around. Yours sounds like it loses alot of power all of a sudden too? Check your fuel system as I had the sudden power loss happen from a sticking needle and maybe jiggling the throttle knocks it loose? I keep listening to the video and it sounds alot like it just suddenly gets really loaded down hard.

It does lose almost all of its power. If I return the throttle to idle it will die, but it always starts right up and runs fine

[Larry in WNY]

Mine was making a tapping sound and somehow the PTO engagement pin was out of the groove and catching the splines of the shaft. First startup after sitting all Winter. I rebuilt my engine too and ran it a couple hours without hearing any strange noises. Then that happens. Strange.

Larry

[Waif]

That is odd, mine sounds kinda like that under really heavy load like up hill cultivating in second gear but it's definitely not a knock in my case just normal engine noise and it dosen't stick around. Yours sounds like it loses alot of power all of a sudden too? Check your fuel system as I had the sudden power loss happen from a sticking needle and maybe jiggling the throttle knocks it loose? I keep listening to the video and it sounds alot like it just suddenly gets really loaded down hard.

It does lose almost all of its power. If I return the throttle to idle it will die, but it always starts right up and runs fine

Original fuel cap?
A plugged cap vent can starve an engine.
As can a clogged filter. Or filter fighting gravity flow.
A chunk of debris floating about ,stuck under suction /vacuum , then free when demand stops.

[Peter Person]

Hayden,
Going back to your engine rebuild, you had some questions on rod bearing orientation and condition. I wonder if something is amiss with them.
http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=108691&p=862224#p862224

[Mahoman]

That is odd, mine sounds kinda like that under really heavy load like up hill cultivating in second gear but it's definitely not a knock in my case just normal engine noise and it dosen't stick around. Yours sounds like it loses alot of power all of a sudden too? Check your fuel system as I had the sudden power loss happen from a sticking needle and maybe jiggling the throttle knocks it loose? I keep listening to the video and it sounds alot like it just suddenly gets really loaded down hard.

It does lose almost all of its power. If I return the throttle to idle it will die, but it always starts right up and runs fine

Original fuel cap?
A plugged cap vent can starve an engine.
As can a clogged filter. Or filter fighting gravity flow.
A chunk of debris floating about ,stuck under suction /vacuum , then free when demand stops.

Yes it does have the original fuel cap however I took the new recall replacement one off my H and used that to stop my fuel leak from the cap and it did the same thing. The tank is clean and I cleaned my sediment bowl during the rebuild and I don’t have another fuel filter.

[Mahoman]

Hayden,
Going back to your engine rebuild, you had some questions on rod bearing orientation and condition. I wonder if something is amiss with them.
http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=108691&p=862224#p862224

Yes I was suspecting that for a while I’m going to pull the pan this winter, my rear main seal retainer has a stripped bolt hole so I’ll have to heli coil that anyway so I’ll take a look at my rebuild job while I’m in there. For right now I’m suspecting the governor because the keyed socket is extremely worn and the engine accelerates very strangely sometimes it won’t accelerate at all and sometimes it will go to full rpm with a tiny movement of the throttle lever.