Weekend Freedom Machines banner
1 - 5 of 5 Posts

·
Banned
Joined
·
30 Posts
Discussion Starter · #1 ·
I have a 140 that surges at low speed. If I hold the hyd. lift lever forward or back the surging stops, and I can drive at low speed also it works fine at full speed. The fluid level is good. Does anyone know what could be causing this problem I'm having?
 

·
Registered
Joined
·
111 Posts
Mike,

Did this issue just start recently? Have you made any changes to the engine recently, or did it just start on it’s own?

Some items you may want to look at (and this is just about word for word out of the manual – excluding issues which would also cause a high speed surge):

1 – Old or dirty fuel.
2 - Idle speed too slow.
3 – Spark plug dirty, fouled, or incorrect gap.
4 – Poor compression.
5 – Faulty breather causing low crankcase vacuum.
6 – Carburetor leaking at gaskets or throttle shaft.
7 – Throttle to governor linkage misassembled.
8 – Throttle to governor linkage adjusted improperly.
9 – Breaker points out of adjustment, worn, or pitted.

Hope this helps as a starting point. Others here may also have additional guidance based on their experiences.

Please let us know if you have any questions.

Tim
 

·
Banned
Joined
·
30 Posts
Discussion Starter · #3 ·
Tim thanks but I think I should word myself better. The engine is not surging. It's the transmission. I have the engine full throttle and if I try low speeds I get a surging unless I hold the hyd. lift lever back or forward. It also works fine when I'm at a higher rate of speed all the while at full throttle. Engine is steady it's the trans making it surge, also the fluid is good and I installed new check valves about two years ago.
 

·
Registered
Joined
·
147 Posts
Mike the first thing I would check is the charge pump and implement relief valve springs. The one just in front of the check valves and the other on the side of the hydro case.

When you remove them be careful not to lose the small shims.

You could have a broken spring or something interfering with their operation.

If you don't find a problem there you will need to get a hydraulic pressure gauge and check the pressure under different conditions.
 

·
Registered
Joined
·
111 Posts
Mike,

Sorry about that, I misunderstood.

You stated you installed new check valves. Did you also install new Charge Pump & Implement Relief Valves?

Possibly at WOT the system pressure is high and the Charge Pump Relief Valve is cycling open and closed until the system opens and the demand for pressure is diverted to the either the transmission and/or implements.

If your check valves are operating correctly, the pump relief valves are the next place I would check.

Performing an Implement Circuit Pressure Check (500 PSI ± 50 PSI – fully open circuit) along with a Charge Pressure Test (1/2 throttle – 75 – 110 PSI) will help to isolate the problem.

Have you done these checks? If so, are you within spec's?

Richard - You type faster than I do.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top