4041 PowRMax 19.5 cckb power loss

[PowRTim]

My 4041 has a relatively new engine. Ituses no oil has good compression. After a few minutes after it warms up, it loses power. This only happens when mowing. If you pull the grounf=d speed back it will come back up to power. I've rebuilt the carburetor and checked the timing. Two of my thoughts are that the rebuild kit did not come with the main adjustment needle and this is bad. The second thought is timing. I think there is a warp in the bottom of the breaker box. I smoothed it out some and was careful not to tighten it to much upon mounting it. The timing moves to the right slightly ( only about2-3 mm) when I tighten the box. Cant get it dead on, but also, the exhaust pie is in the way ( it looks different from viewing below pipe and above pipe. Is this small degree of timing that important? Also, why is it powerful for the first few minutes before it heats up. Would appreciate any help, very frustrating. Thanks

[CleanBee]

A coil when heated up can cause a power loss. It may have a small crack in the insulation that expands when heated causing a short. Main needle issues usually cause a searching at idle on these motors, if your needle has any pitting or a grove I would replace it. If the needle is bad, usually the owner ends up running the tractor on the rich side. Dan

[D-17_Dave]

Is the timing that important? YES. If the points box has any movement after you "tighten" it then you need to fabricate a spacer or simular to help lock it in place. Or replace it if needed. As said above, a coil or condenser that is comprimised or contaminated with fluid, either oil vapor or water will when hot short out the component and cause it to fail. In your case partially fail and cause a lose of ignition or a change in timing. One way to isolate a fuel problem is when the condition occurs lightly apply the choke. If the engine recovers then you have a fuel starvation problem like a blockage or a failing fuel pump. If the choke doesn't help then you likely have an ign. problem and the coil or cond. is your likely candidate.

[dhardin]

Loss of power is kind of a vague description? Dose the RPMs drop under a load? or will the RPMs stay about the same but slow down. Bad fuel pumps are common and a luckily cause. Another cause could be a crack in one of the gas lines causing it to suck air once it gets running. Valve lash is also a possible issue, once it warms up the valves expand and takes them out of a working tolerance. I have seen the throttle not hold tight once it warms up and slide back (but you should see that). But the Number one issues i have seen when the RPMs stay about the same but loose power is the 2 dive belts are worn.