Ford 655A Backhoe Motor Issues — What Can Go Wrong and What to Check

[MikePhua]

The Ford 655A Backhoe Loader — background and specs
The Ford 655A is part of a line of loader‑backhoe tractors built by Ford (later Ford/New Holland) in the mid‑1980s. It belongs to a class of versatile machines combining a front loader and a rear backhoe—designed for construction, utility, farm and small‑site jobs.
Some key specs to understand the 655A’s design envelope:

• Operating weight: about 14,830 to 15,825 lb (≈ 6,725–7,180 kg) depending on whether it's a standard or extendible backhoe configuration.
  
• Hydraulic pump flow (implement pump): about 28.5 gallons per minute (≈ 108 L/min), using an open‑center hydraulic system.
  
• Transmission is not a hydrostat; it's a conventional transmission/torque converter setup typical of loader-backhoes, with drive wheels 2WD (in many 655A variants) and wet‑disc brakes.
  

Because of its design — loader, backhoe, manual transmission and torque converter — the 655A was built for general purpose work: digging trenches, light-to-medium excavation, loader‑bucket duties, and general farm or construction tasks.
But older machines like the 655A (many now 30–40+ years old) can develop “motor issues” that often mask larger system health problems.
Common “Motor Issues” and Root Causes on 655A
When operators report a “motor issue” on a 655A — e.g. engine cranks but fails to run, or runs poorly, or sputters — the root cause is often not the engine itself but the fuel supply and injection pump system. Based on field experience and documented restorations, the following problems appear frequently:

• Fuel supply pump failure. The 655A uses a supply pump feeding the injection pump. Many times, after long idle periods or lack of use, the supply pump fails to draw fuel properly. Even if someone uses the hand‑prime lever, that doesn’t guarantee fuel reaches the injection pump.
  
• Injection pump lubrication oil missing. The injection pump on some 655A units requires its own dedicated oil (same type as engine oil) — if the pump’s internal reservoir is dry, pump internals can shear or fail.
  
• Faulty cold‑start or throttle controls. On some units, the cold-start (choke or starting enrichment) button linked to the shut‑off lever may have failed — without it the engine may crank but not fire.
  
• Debris or blockage in pre‑screen/fuel pickup inside pump. Even when filters are changed, small particles — plant matter, wood shavings, or other debris — may clog the screen in the pump suction, starving fuel supply and preventing proper injection.
  

Because the fuel/injection system on an old machine can be finicky, “motor issue” often means something other than a worn-out engine — yet symptoms can appear similar (no start, poor idle, weak acceleration).
Why These Issues Are More Common on Older 655A Machines
There are structural and usage-related reasons 655A backhoes tend to show fuel‑system problems over time:

• Many units have sat idle for years (idle sits without fuel draws lead to varnish, gumming in fuel lines, degradation in pump seals).
  
• Fuel contamination: if stored with dirty diesel or exposed to moisture, sediment builds faster, clogging pre‑screens or filters.
  
• Service history gaps: older user or fleet owners may have changed filters but never checked the internal pump reservoir oil or the pre‑screen — so problems accumulate invisibly.
  
• Aftermarket improvisation: some repairs are done in the field without complete parts and procedures (e.g. fuel lines spliced, pumps primed poorly), increasing risk of pump starvation or failure.
  

Steps To Diagnose A “Dead” 655A Backhoe Motor
When facing a non‑starting or weak‑running 655A, a logical diagnostic sequence saves time and avoids misdiagnosis (which might lead someone to replace the entire engine unnecessarily). A well‑tested routine looks like this:

• Disable the fuel shut‑off (ensure lever is in “run” position) and check that the supply pump is actually delivering fuel. Loosen the inlet line on the back of the pump, crank the engine; fuel should spurt visibly — if nothing comes out, the supply pump is not working.
  
• Check the oil level in the injection pump’s internal reservoir (through the filler cap on top, drain plug on bottom, and “FULL” plug on side) — if oil is absent, the injection pump is vulnerable to failure.
  
• Examine the pre‑screen (a small screen/suction filter inside the pump pickup) — remove the access plate and inspect; often it is clogged by debris that survives filter changes. Cleaning or replacing the screen can restore fuel supply.
  
• Check cold‑start and throttle controls (especially the cold‑start button inside shut‑off rod, if so equipped). Confirm that the shut‑off lever is in the correct position and that the cold‑start circuit is functional (you should hear a “click” or feel a detent when the button engages).
  
• If engine does fire but runs roughly or dies under load, monitor fuel supply while the engine is running under cranking and at idle — fluctuating fuel delivery often shows fuel‑pump or injection‑pump issues rather than mechanical engine wear.
  

If these steps rectify the fuel supply and pump lubrication, chances are the “motor issue” was not the engine block or injection timing — but a fuel delivery problem that can be fixed for a fraction of the cost of engine replacement.
When The Issue Is Worse — Pump Internal Damage And Repair
If, after cleaning the pre‑screen, topping the pump oil, and confirming supply, the engine still fails to hold consistent fuel pressure or stalls under load, deeper issues may exist inside the injection pump. Common internal failures include:

• Broken or weakened plunger return springs — leading to weak or no fuel delivery from one or more pump plungers. This often shows in poor starting or rough running.
  
• Worn cam lobes or tappet surfaces inside the pump — reducing effective pump stroke and decreasing fuel volume delivered per injection cycle. Over decades, metal fatigue may degrade pump performance below workable limits.
  
• Corroded or hardened pump internals (barrels, plungers, seals) — especially if moisture or stale fuel was left in the system — leading to sticking or weak injection, misfires, or refusal to fire.
  

Repair involves complete pump disassembly, internal inspection, replacement of springs/plungers/seals, re‑lubrication, and recalibration. Because this procedure requires precision and specialized knowledge, many owners entrust it to professional injection‑pump specialists rather than attempt DIY. In historical user reports, this often brings old 655A backhoes back to solid operational condition — sometimes after years of sitting idle.
Maintenance Guidance To Avoid Future Motor Problems
To prevent recurring fuel‑system and motor issues on a 655A (or similar vintage backhoe), a careful maintenance and usage protocol is advised:

• Always prime the fuel system properly after any period of storage — use the hand‑pump, then check for actual fuel delivery from the supply pump.
  
• Check and maintain the oil level in the injection pump’s reservoir (use same-grade oil as engine) during every oil change interval.
  
• Replace fuel filters regularly, but also inspect and clean the pre‑screen pickup if the engine has lost prime, sat idle or was contaminated — filters alone do not guarantee clean supply.
  
• Use clean, fresh diesel fuel and avoid storing fuel long-term in tanks without proper condensation or water separation — water contamination accelerates internal corrosion and varnish formation.
  
• Before storing the machine long-term, consider fogging or lubricating internal pump components (if recommended for your region) — to prevent corrosion during idle months.
  
• On re-commissioning after prolonged storage, run at idle and moderate throttle until you are sure the fuel supply and injection are stable — avoid full load runs until confirmed.
  

A Real-World Story: Bringing a 655A Back to Life
One owner bought a 1985 655A that had sat unused in a yard for nearly a decade. The hour meter was unverified and the previous owner had long forgotten maintenance history. On first attempt the machine cranked but failed to fire. Rather than assume a seized engine, the owner followed the diagnostic routine:

• Verified the fuel supply pump produced no fuel until he loosened the inlet line — it was clogged and the supply pump diaphragm was stuck.
  
• Cleaned the pre‑screen filter and replaced it.
  
• Added engine-grade oil to the injection pump reservoir.
  
• Checked the shut‑off lever and cold‑start button — both were corroded but functional after cleaning contacts.
  
• Attempted start: the engine fired immediately, idled roughly at first but smoothed out after some idle running.
  

Within a week, after cycling loader and backhoe functions lightly, the owner had restored a previously “dead” machine to full working order — at a total cost under US$300 for filters, oil, and a few small parts. What initially looked like a “motor rebuild” scenario turned out to be a simple fuel‑system restoration.
Why Understanding Fuel Pump Details Matters on Old Backhoes
The 655A (and its siblings 555A/555B) belong to an era when backhoes were built to be serviceable and long‑lived — but also required regular attention to fuel and hydraulic systems.
Because injection pumps are mechanically lubricated and fuel supply depends on suction screens, seals and small valves, neglect (especially during storage) quickly translates into “motor problems.” For any owner or buyer of an older 655A, understanding this is crucial:

• It prevents unnecessary engine rebuilds or replacements when the real issue is upstream.
  
• It saves money and time — fuel system parts and pump oil cost far less than full engine work.
  
• It makes bringing dormant machines back online far more realistic — used‑after‑storage restorations of 655A units remain common among enthusiasts and small contractors who value the loader‑backhoe’s versatility.
  

Final Thoughts: 655A Is Still Worth Saving If You Know What You’re Doing
The Ford 655A backhoe loader is not fast or modern by today’s standards — but its simple mechanical layout, reasonable hydraulic flow (≈ 28.5 gpm), workable loader/backhoe geometry, and robust construction still make it a viable machine for small-to-medium jobs, rural work, repair yards or hobby farms.
If you feel you’ve got a “motor issue” on a 655A — missing start, poor idle, weak performance — don’t immediately assume the worst. First walk through the fuel supply inspection, injection‑pump oil check, and pre‑screen cleaning. In many cases, owners report that such attention revives these machines after years of rest. For anyone willing to spend a few hours and modest parts cost, a 655A can easily become a dependable workhorse again.