What is the internal difference between JPR-YM08IH and model JPR-YM08IH2? The difference is the thickness of the machined "Cam" which is incorporated or part of the Body / Casing itself. The machined thickness of YM08IH is greater (4mm) vs a smaller thickness (2mm) found in the JPR-YM08IH2, so the JPR-YM08IH model will give a higher flow rate vs JPR-YM08IH2. This is why it is very important to order the correct pump for your model of the engine by referring to the cross-reference information provided.
Note: You can also use JPR-YM08IH for the replacement of Yanmar 121575-42000 (replaced by 721575-42702), which is the pump with the NPT threaded nipple port design, but you MUST make sure that you have the rubber hose for the inlet and outlet for the JPR-YM08IH hose connections.
How to Install Mounting Bracket on Pump? The mounting bracket does not come pre-installed on the pump; if you are using this bracket for your application you can find the step-by-step installation instructions by going the Blog Page Post "How to Install Mounting Bracket on JMP Marine Yanmar Replacement Engine Cooling Pumps JPR-YM08IH & JPR-YM08IH2"
Port Size (Inside Diameter)
Port Size (Outside Diameter)
Approx 3/4" HOSE
Uses JMP Impeller p/n
7050-01 (search 7050-01K)
Pump Size (LxWxH,mm)
91 x 114 x 76
Pump Weight (approx)
4.0 lbs (1.82 kgs)
Replaces Genuine Yanmar Pump p/n(s)
Yanmar 128397-42500, 128990-42500
2GMF, 3GMF, 2YM, 3YM
Replaces Johnson Pump p/n(s)
Johnson 10-24509-01, 10-13337-01, F4B-903
Parts Internally Compatible to Genuine
NO(Internal Changes made for better performance & Reliability)