Throttle dropped to about 1400 rpm and will not go any higher on my 5600 Tool Cat

governors always stop in the full throttle position
when the engine starts the governor action is to move to the idle position against spring tension
the higher tension the higher the rpms
moving the throttle lever increases the spring tension on the governor lever an so the rpms increase
from what you say there is something wrong with the governor/ spring set up
from your photo the system may be reversed and the spring pulls to idle in which case the throttle will decrease the spring tension for higher rpm
which ever way check where the spring is located

Depressing the throttle slightly we listen to the engine. If the engine hesitates to accelerate, the LO screw should be opened 1/8 of a turn. If we open the screw too much, the engine will not accelerate smoothly and start shaking (too rich of a mixture). In this case we should close the LO screw slightly. We repeat this procedure until the engine reacts smoothly when adding power. Meanwhile, a readjustment of the idle speed may be needed.

After the LO mixture has been adjusted, we proceed with the HI screw adjustment. After securing the paramotor, we open the throttle to full power. We turn the HI screw to the left or right until the maximum RPM is reached. From this position just a slight turn to the right should cause a significant RPM drop. This means the lean side of the mixture has been achieved. Immediately we OPEN the screw to the left to prevent the engine from overheating!


Let us repeat once again this critical step:


At full power we tune for maximum RPM, then we close the HI screw more, until a drop in RPMs is noticed. When the drop in RPMs occurs we open the HI screw again until we reach maximum RPMs once again, and then we open the screw more until we have a drop of 20 to 60 RPMs. In this position the carburetor will be perfectly tuned slightly on the rich (safe) side.


Next, we should close the throttle and recheck the idle and the LO screw adjustment. If the carburetor was tuned properly, the idle will return to the normal setting described above.

To put it in a nutshell, if the engine idles and accelerates smoothly, does not smoke heavily and achieves 20- 60 RPM below maximum RPM, the carburetor is tuned correctly.

Depressing the throttle slightly we listen to the engine. If the engine hesitates to accelerate, the LO screw should be opened 1/8 of a turn. If we open the screw too much, the engine will not accelerate smoothly and start shaking (too rich of a mixture). In this case we should close the LO screw slightly. We repeat this procedure until the engine reacts smoothly when adding power. Meanwhile, a readjustment of the idle speed may be needed.

After the LO mixture has been adjusted, we proceed with the HI screw adjustment. After securing the paramotor, we open the throttle to full power. We turn the HI screw to the left or right until the maximum RPM is reached. From this position just a slight turn to the right should cause a significant RPM drop. This means the lean side of the mixture has been achieved. Immediately we OPEN the screw to the left to prevent the engine from overheating!


Let us repeat once again this critical step:


At full power we tune for maximum RPM, then we close the HI screw more, until a drop in RPMs is noticed. When the drop in RPMs occurs we open the HI screw again until we reach maximum RPMs once again, and then we open the screw more until we have a drop of 20 to 60 RPMs. In this position the carburetor will be perfectly tuned slightly on the rich (safe) side.


Next, we should close the throttle and recheck the idle and the LO screw adjustment. If the carburetor was tuned properly, the idle will return to the normal setting described above.

To put it in a nutshell, if the engine idles and accelerates smoothly, does not smoke heavily and achieves 20- 60 RPM below maximum RPM, the carburetor is tuned correctly.

you assumption is right
the pump is operating at idle as at full rpms and is controlled by pressure relief valves
When demand for pressure is low the valves will be partially opened and will operate when the pressure is reduced ( ram valve is moved)
Higher rpms maintain the pressure for faster ram operation
I would suggest that you have the system pressure tested by a service centre as it could be a malfunctioning valve (solenoid) or a failing pump

The cars computer has a rev limiter built in so a no load rev is about 2 grand. but driving the car it should reach 4800 rpms or 5600 rpms if not then install a vacuum gauge on a intake manifold port normal readings should be 16 inches or more at idle then drive car as you accelerate to a higher speed this should drop slightly once at full throttle is will read almost zero if below that then the exhaust has a restriction.

It sounds like your float in your carb is getting stuck at high rpms. Try taking the bowel off and pushing the float up(make sure to have a bucket for fuel to run into). If it sticks that's the issue an easy fix.

Check for stuck throttle plate. Check pcv hose that goes to the intake manifold. They get soft and leak, check while running.

CHECK THE STATUS OF THE AIR FLOW SENSOR AND THROTTLE POSITION SENSOR

Most chainsaws and small engines are 1.5 turns out.

You need to set the mixtures for the carburetor. You will find a Low and High adjustment screw. At idle turn the screw in or clockwise until the rps starts to decrease. Then start turning it out till you hit max idle rpms. Turn screw back in a quarter to half turn and it should be idling smoothly. Be careful here and get someone to hold saw if necessary but hold in throttle to full speed and do the same with high adjustment screw. turn it in till rpm starts to drop then back it out until you get to max rpm and it won't go any higher then turn it back in a half a turn.

You will find a Low and High adjustment screw. At idle turn the screw in or clockwise until the rps starts to decrease. Then start turning it out till you hit max idle rpms. Turn screw back in a quarter to half turn and it should be idling smoothly. Be careful here and get someone to hold saw if necessary but hold in throttle to full speed and do the same with high adjustment screw. turn it in till rpm starts to drop then back it out until you get to max rpm and it won't go any higher then turn it back in a half a turn.