Starts easily but wont run under load???

jefftinker

Member
Joined
Jan 20, 2020
Threads
1
Messages
10
Now getting back on track.
Start your engine then get off and manually open the throttle butterfly bu pushing on the governor rod.
The engine should accelerate up to about 4000 rpm without faultering,
If it does this then the governor is at fault.
'If it dosent then you have an engine problem
ok tried that and it still stalls out so i guess its the engine. would it be a easy fix or just junk it.
 
Last edited:

Hammermechanicman

Lawn Addict
Joined
Jan 10, 2020
Threads
49
Messages
3,484
When you did the test bertsmobile1 told you where you open the carb butterfly manually and the engine stumbles I would suspect the main jet in the carb needs cleaned. You might remove and clean the carb before pulling the head to check the valves.
 

jefftinker

Member
Joined
Jan 20, 2020
Threads
1
Messages
10
When you did the test bertsmobile1 told you where you open the carb butterfly manually and the engine stumbles I would suspect the main jet in the carb needs cleaned. You might remove and clean the carb before pulling the head to check the valves.
it has a new carb fuel filter and fuel lines. sounds like more troble tahn its worth if i have to rebuild the engine
 

one_fjr_pilot

Forum Newbie
Joined
May 27, 2020
Threads
0
Messages
1
Now getting back on track.
Start your engine then get off and manually open the throttle butterfly bu pushing on the governor rod.
The engine should accelerate up to about 4000 rpm without faultering,
If it does this then the governor is at fault.
'If it dosent then you have an engine problem

Bertsmobile, when you say "if it doesn't then you have an engine problem" - can you elaborate? My crafstsman T2500 is not that old and just started doing as described in the original question. sputters under load. I replaced the fuel and fuel filter, cleaned the jets and carb with carb cleaner, cleaned the air filter and tried your procedure above, it runs fast and clean when you operate the governor rod, but when you run it at full throttle (mowing, or just driving it) and the pedal is all the way down it sputters. Running at lower throttle it does not sputter, but is clearly too slow to mow. :)

Your thoughts are much appreciated!
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
You have to understand that an engine under load requires more fuel than an engine with no load on it.
This is why we call an unloaded engine running @ 3500 prm a "HIGH IDLE" becaus that is exactly what it is doing
Running on the idle jet or most likely 90% idle & 10 % main jet.
When you load the engine by putting the blades on the throttle has to open further in order to spin at the same speed.
IT is exactly the same as you driving up a steep hill.
You put your foot hard down on the gass but the engine spins at exactly the same speed.
So the governor allows the throttle to open wide and when that happens any obstruction to the main jet or extra effort to draw the fuel into the engine ( low float level ) will cause the engine to faulter
Squirting goo up a carbs skirt is not cleaning the carb
IT has to be dissassebbled and cleaned manually , or soaked in a strong solvent or subjected to ultrasonic cleaning to do it properly.
If you go through all of the posts here you will find hundreds when the original posted started out saying they had cleaned the carb
Then they get directed to soewhere like the outdoor power Equipment site which shows how to do the job properly
25 % come back to say thanks, I did it proprly & now the mower runs fine
70% just vanish so we can assume the cleaning worked
5 % come back with another problem because the cleaning did not work.
 
Top