Yanmar builds tough little diesels, and it builds some of their injection pumps in-house. The YPES is one of them: a Yanmar inline pump found on some of the company’s smaller engines.
We will be straight with you. Public information on the YPES is thin, so this page leans on what matters most: identifying your pump from its tag. Send us a clear photo, and we will confirm what you have before you pull anything off the engine.
Also Known As
Owners and parts sites use a handful of names:
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Yanmar YPES or “YPES pump”
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“Yanmar inline injection pump”
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Pumps identified by a Yanmar number such as 719xxx-51xxx
How the YPES Works
An inline pump gives every cylinder its own plunger, lined up in a row like soldiers on parade. A camshaft lifts each one in turn, and a control rack sets how much fuel each stroke delivers.
That makes it different from Yanmar’s MP distributor pump, which uses one pumping element and a rotating distributor to serve every cylinder.
Shop Talk: Inline or distributor? Look at the outlets. Outlets standing in a straight row usually mean inline. Outlets grouped around one head usually mean a distributor pump.
What It Fits
| Make and model | Engine | Years | Notes |
|---|---|---|---|
| Yanmar TNV-series engines | Some TNV82A and TNV88 | 719xxx-51xxx numbers appear on some of these pumps | |
| Older Yanmar TN-series engines | Three-cylinder TN84 family | One parts listing ties the YPES name to a John Deere 955 | |
| Compact tractors, mini excavators, generators | Various Yanmar | Read the tag before ordering anything |
Part Numbers We See
Yanmar injection pump numbers commonly follow a 7xxxxx-51xxx pattern. On some TNV82A and TNV88 pumps that number starts with 719. The equipment maker may add its own number too.
Owner’s Tip: Before you call, photograph the pump tag, the engine’s model plate and the machine’s serial plate. Those three photos answer most of our questions in one go.
Why YPES Pumps Fail and the Symptoms
Like any inline pump, the YPES wears from dirt and water in the fuel and sticks from varnish when a machine sits. Seals harden with age.
Common symptoms:
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Hard starting
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Low power under load
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Black or white smoke
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Rough or hunting idle
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Fuel leaking from the pump
What We Do to Your YPES
| Service option | Typical evaluation or service scope |
|---|---|
| Test and report | Identification, bench test as received, written results and a service recommendation |
| Rebuild and calibrate | Teardown, cleaning, worn parts and seals replaced, delivery set on the bench |
| Exchange (when available) | Ask whether a compatible exchange unit is available and how the core process works |
What Model-Specific Verification Can Document
Evidence for Yanmar YPES: When an approved procedure exists for this exact component, useful documentation can distinguish identification, visible condition, observed wear or contamination and supported functional test results. Record the assembly number and available engine data before deciding which checks will answer the reported complaint. Bench findings cannot replace the engine-side diagnosis. See how pump testing is evaluated.
Repair Options and Technical Considerations
Repair decisions depend on the exact pump, its condition, the components required and the service approved after evaluation. Ask about any available exchange options and review the service scope before authorization. Parts availability for your complete identification is central to determining serviceability.
How to Ship Your YPES
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Send tag photos first so we can confirm the pump.
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Note the engine model and serial number.
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Drain the fuel and cap every fitting.
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Bag the pump and pack it in at least 2 inches of padding.
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Complete the mail-in form, include a copy and ship to the address provided during intake with tracking.
Ship It Right: Small pumps rattle around in big boxes. Fill every gap so it cannot move when you shake the box.
Related Pumps and Parts
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Yanmar MP pump, the distributor pump on many TNV engines
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Yanmar TNV engine guide
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All Yanmar pumps
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Injector repair
FAQ
How do I know if I have a YPES or an MP pump?
Look at the outlets and the tag. A row of outlets suggests an inline pump like the YPES; outlets around one head suggest the MP. A tag photo settles it.
Can you rebuild a YPES?
Send it in for evaluation, and we will tell you plainly what can be done.
My tag is unreadable. Now what?
Send the engine model, engine serial number and a few photos of the pump. That is often enough to narrow it down.
Should I send the injectors too?
If the engine smokes or knocks, yes. A fresh pump cannot fix a dribbling nozzle. See injector repair.
Small engine, small pump, big headache when it quits. Send us the tag photo and let us take it from there. Start a Mail-In Repair or request a repair evaluation.