154 has me scratching my head...

[bigys73]

Here's the problem, when I start the tractor cold it runs real rough, spits and sputters, chokes out, just sound terrible. Until it gets warmed up and hot then it smooths out and runs pretty well... To me it sounds like an air flow or air mixture problem. Something must swell shut after it gets hot. I've soaked the carb and rebuilt it, checked all fuel lines, changed the points and condenser.
If anyone thinks they can shed some light on the problem I would greatly appreciate it. Thanks.

[Bigdog]

Possibly an air infiltration around the intake manifold. If you are very careful you can take an unlit propane torch and move it around the manifold sealing surfaces. If it is sucking air anywhere it will smooth out when the propane is drawn in.

[Eugene]

Agree with BigDog. Sounds like there is a vacuum leak - some place. Check the gasket between the carburetor and manifold. Since you rebuilt the carburetor, double check the mating surface on the manifold at the carb/manifold junction.

Suggest doing a full - complete tune up including valve tappet adjustment - etc.

[BigBill]

Here's the problem, when I start the tractor cold it runs real rough, spits and sputters, chokes out, just sound terrible. Until it gets warmed up and hot then it smooths out and runs pretty well... To me it sounds like an air flow or air mixture problem. Something must swell shut after it gets hot. I've soaked the carb and rebuilt it, checked all fuel lines, changed the points and condenser.
If anyone thinks they can shed some light on the problem I would greatly appreciate it. Thanks.

Does it spit and sputter when the choke is on?
How is your float level?
Your spark plugs can be carboned up too from too much gas.

My last 154(#3) when i go to start it up its very sluggish but i have to pull the choke out crank it and push the choke in right away to start it. The throttle is at the idle position. It has the IH carb and i think the float level is too high because it seems to get too much gas when the float is pulled out. When its warm it runs awesome.

My first 154 will start when the choke is all the way out and run will its warm but then after a while it will sputter from too much gas. I don't wait that long to push the choke in. (zenith carb) Again the throttle is at the idle position. It runs great when its warm. I think its running normal with a hand choke.

To me setting the float levels can be really finiky at times. The normal setting is a starting point and if its still not right we need to tweek it to make it right. When i run into this happening i think the PO or someone else bent the float tangs a bit too much or in the wrong place to adjust the float level. Now its up to us to make it right. Sometimes its adjusting it a tad more low so it shuts off the gas in the right spot.