Description

Iseki SG173H, SG173H-E20S, UE20S, U48E20, U48E20S Parts Catalog – What the Workbench Needs

You’ve got a lawn tractor down with a busted suction filter and the parts guy wants a part number you don’t have. Or you’re staring at an exploded diagram from a third-party site and the numbers don’t match the casting on the housing. That’s why this Iseki SG173H, SG173H-E20S, UE20S, U48E20, U48E20S Parts Catalog exists – 177 pages of factory-sourced part codes, reference numbers, and interchangeability notes that tell you exacty what goes where and what replaces what.

Parts Catalog vs Service Manual: Why You Need Both

A service manual tells you how to take it apart and put it back together. A parts catalog tells you which threaded fastener belongs in which hole. This is the latter. If you’re rebuilding an Iseki lawn tractor, you need both. The catalog breaks down every assembly by figure number – filter assemblies, steering components, engine mounts – and gives you the exact Iseki part code. Page 2 shows you how to read the head paragraph: KEY number, PART CODE, DESCRIPTION, QTY, and which models it fits. Without this, you’re ordering by guesswork and hoping the bolt bin has something close.

Reading the Codes: ITC, Color, and Model Suffixes

Iseki stamps a lot of information into a few characters. The catalog includes a full explanation of ITC codes – interchangeability symbols that tell you if a new part can replace an old one (OLD ← NEW) or if they’re not interchangeable (OLD ⇆ NEW). Also on page 2: color codes for painted parts, with spray-type paint numbers and drum quantities. If your tractor’s hood needs the factory “4G CRYSTAL BLUE,” the catalog gives you Iseki’s color code and the exact paint part number. Don’t trust a rattle can match from the auto parts store – get the OEM color code right.

Model Variants: SG173H, SG173H-E20S, UE20S, U48E20, U48E20S

This catalog covers five base models plus multiple sub-variants like U48E20S, U48E40, U48E50, and the U4BRE40. Each suffix matters. Page 1 notes: E20 is for Germany, E40 for UK/Oceania, E50 for France, and “U” means power steering. The “S” suffix indicates a specific engine variation (E374-G01). If you order a filter for an SG173H-E20S and your tractor is actually an SG173H (non-E20S), the part may not fit. The catalog lists each part’s quantity per model in the “TYPE OF MODEL” column – you can see at a glance which parts are standard (*) and which are optional (T) or replacement (R).

How to Order the Right Part Using This Catalog

Step one: locate the figure number for the system you’re working on – say, the suction filter. Find the assembly drawing, note the KEY number, and cross-reference it in the parts list. The list gives the part code (e.g., 1614-508-200-00 for a FILTER ASSY). Then check the REMARKS column for any supersession notes or “SET” part numbers. The catalog explains that parts marked with the same letter in the REMARKS column can be replaced as a set. Example: if your old filter is marked “A” and a new assembly is “B,” you can swap them as a unit. That’s the kind of info that saves you from buying a filter that won’t bolt to the bracket.

Source Authenticity: OEM Iseki, Not Aftermarket

This is the factory parts catalog – the same PDF that Iseki dealers use. It’s not a scanned reprint from a third-party publisher or a cobbled-together list from a forum. The part numbers start with “V” or “W” for standard market parts, but every Iseki-specific code is original. Aftermarket catalogs often leave out interchangeability notes or use generic descriptions. Here, you get the actual Iseki part code, the exact quantity per machine, and the color code if it’s a painted component. If you’ve ever had a return because a part number was off by one digit, you know why OEM documentation is non-negotiable.

Need a power steering pump seal for a U48E20S? This catalog has the O-ring part code (V721-313-100-00) and the figure reference. The page count – 177 pages – covers every assembly from the engine to the mower deck. Iseki TS3110 Parts Catalog – Factory OEM Parts Breakdown covers a different platform, but if you’re working on the SG173H line, this is the one. Also check out Iseki TXG23 TXG23FH TXG23TH TXG23E 2003 Parts Catalog and Iseki TXG23 Parts Catalog – Factory OEM Parts Breakdown for other models in the same family.

For background on why OEM parts catalogs matter in the broader industry, see Automotive Industry Overview and Automotive Industry Overview.

FAQ – Iseki SG173H Parts Catalog

Does this catalog include engine overhaul specs like ring gaps and bearing clearances?

No. This is a parts catalog – it lists part numbers and quantities. You need the factory service manual for clearances and torque values. The catalog only covers replacement parts.

How do I read the ITC symbol for interchangeability?

Page 2 has a full key. OLD ← NEW means the new part supersedes the old. OLD → NEW means the old part can be used in place of the new one – rare but happens. OLD ⇆ NEW means they are not interchangeable. Always check the ITC column before ordering.

What is the difference between U48E20 and U48E20S?

The “U” prefix means power steering. The “S” suffix indicates engine variant E374-G01. If your machine has power steering but no S, you need U48E20 parts. The catalog lists each part’s applicability in the TYPE OF MODEL column – use that to verify.

Can I use this catalog to find paint codes for my Iseki tractor?

Yes. Page 2 includes a color code table with spray-type paint numbers and drum quantities. For example, Crystal Blue is color code 4G with paint number 1300-951-001-10. The catalog lists color codes for each painted part.

If you’re tired of ordering parts that don’t fit and returning them, this catalog gives you the factory data to get it right the first time. Access the Factory Manual.