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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26014
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a model #31C707 in a TroyBuilt mower. While mowing I

Customer Question

I have a model #31C707 in a TroyBuilt mower. While mowing I lost engine RPMs. It will start OK, but it wouldn't raise the engine speed above a high idle. Even with the throttle lever raised to full. What might cause this abrubt loss of RPMs?
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Is throttle cable moving at lower control? Are springs on place?

Customer: replied 1 year ago.
The throttle lever is connected and springs are in place.
Expert:  Curtis B. replied 1 year ago.

Is the cable slipping under the clamp?

Customer: replied 1 year ago.
No. I can manipulate the throttle valve directly on the carb. But it still wouldn't come up to speed.
Expert:  Curtis B. replied 1 year ago.

Is the carburetor loose on the cylinder head, may a bolt fell out!

Expert:  Curtis B. replied 1 year ago.

If not, have you drained the carburetor and checked for water?

Customer: replied 1 year ago.
It runs. I can shut it off and restart it. I just can't raise the RPMs.
Customer: replied 1 year ago.
I can raise and lower the RPMs with the carb throttle valve, it just wouldn't raise higher then a high idle.
Expert:  Curtis B. replied 1 year ago.

See if the throttle valve is loose on the shaft!

Customer: replied 1 year ago.
No. The valve is firmly on the shaft.
Expert:  Curtis B. replied 1 year ago.

Remove the solenoid in the carburetor, it may be sticking, and it will let you clean the float bowl.

Customer: replied 1 year ago.
I did clean out the bowl and float valve.
Expert:  Curtis B. replied 1 year ago.

Does the engine have the pulse fuel pump? Is it working?

Customer: replied 1 year ago.
Is that the thing hanging under the carb bowl? The engine wouldn't start with it unplugged. It started after I reconnected the wire. Is that the pulse fuel pump?
Expert:  Curtis B. replied 1 year ago.

no, that is anti-backfire solenoid, it plugs the main jet. Fuel pump would have three lines, between tank and carb.