Throttle and carby settings for honda hru 215 just runs at the same revs whether on low or high

Sounds like lung failure rather than fuel, If it is lumpy at idle it is usually air/fuel mix may also be sucking air at carby vibration mount.Maybe a full test before replacing anything else will tell the story. see points below to concentrate on.

Check inlet and exhaust valve clearances, they are very finicky.
Secondly the fuel tap at tank sometimes gets shellac inside and restricts flow. have you done:
a) a fuel flow test?
b)cylinder compression test
c) Exhaust emission /flow test?
Air leak test at carburettor manifold mounts - Aerostart, ether spray or lpg sprayed at mounts while running. WARNING these are flammable so just quick bursts. If concerned fine mist of water from spray bottle will do the job. What you are looking for is a change in revs while spraying at joints.
Good luck
AJ

Set both the high and low mixture settings two full turns back from the closed setting(full clockwise).. Set idle speed for all ahead full.

Start sucker and after a warmup throttle it down and then start adjusting the low mixture screw for fastest idle. Then lower idle some more but not to point where it starts to run rough. Then rev the sucker to high speed and adjust the high mixture for max speed. You may have to make a slight adjustment on the high speed to get a smooth transition from low speed to high.

Check your govenor linkage and action. Your engine has a plastic gear running the govenor inside the crankcase.

Hi if it stop when the trigger is pulled the issue is with the motor.
stopping is caused by , low revs on motor or low compression or poor spark, sometimes faulty carby.
change spark plug , adjust valve ( when valve has some slight side movment it is ok if up and down , it should be tighter (valves usually under side cover near top ) increase revs a little ( make sure revs dont get rough when running high) set max revs to when the engine still runs smoothly at max.

check for a full fuel flow to the carby
indicates a low fuel level possibly float level
check that there is a heat insulation block between the head and the carby
maybe head heat is tending to boil off the carby fuel if too low a level

Turn the engine off, Put the throttle
lever to the HIGH position. Loosen the
pinch bolt nut on the governor arm a
turn or two; just enough that the arm will
move on its shaft.

With one hand, move the governor
arm so that the throttle plate of the
carburettor is wide open. With your other
hand, use smallish pliers that's
why there is a flat on the shaft to turn
the shaft in the same direction. Hold
everything in that position and tighten
the pinch bolt.


You've just taken all the slack out of the governor linkage.

Recheck the choke, idle and maximum RPM
and you've done all the adjusting
you can do.

fuel pump could be the cause but also the float in the carby could be not set at the right level and starve the motor at high revs .

The air looks after itself when you operate he throttle. This how you adjust the fuel....There are two screws on the carby marked L and H. Turn these only 1/8th of a turn at a time. Start with H (high) with the saw at full revs. Turn anti clockwise untill you get max revs then turn it back a little bit. If its running too lean it will over heat the motor and damage it. Then if needed adjust the L (or Low)screw. If you get black or grey smoke when you push the throttle up from idle to full its too rich so turn clockwise. If if slows before it picks up to full revs turn anti clockwise.

Hi this most honda engines dont have a mixture adjustment screw they only have a air bleed adjusment on the front of the carby close to the head though you can only move it a bit either way on some others should be about 2 turns out from closed, the main problem that honda engines have is they will still run with water in the carby , I would try cleaning out the carby bowl first its only held on with a bolt in the centre.