OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk GV150 tuneup help needed

I can't identify that device. It looks as if it is a press tool, probably for installing a seal or bearing (or maybe one of each), but I have no idea what its specific application was.

To move forward with this top seal problem, I suggest you measure the diameter of the crankshaft, where the oil seal runs on it. If you look at the diagram from the parts list, you can see a parallel section (circled in red) just below the flywheel taper, then a step up to the larger diameter for the inner ring of the ball race:


According to the engine repair manual, the oil seal diameter (circled in red) should be 21 mm, and the ball race diameter right below it, should be 25 mm. If you confirm those diameters, we will know that the workshop manual refers to the engine you have. I can't see how it can be otherwise: your serial number fits for a GV150 K1 (that is, not an early production GV150) but let's just make sure we are all talking about the same engine. So far I have never known a Honda workshop manual to talk nonsense, but we all have new experiences every day.

Here are the production records for the GV150. As you can see, they were all made in Japan:


The reason I want to be very sure about this, is that the Honda spare parts list seems to only show a 25x41x6 oil seal (part number 91201-Z0T-801). This would be the right size to fit on the same diameter part of the crankshaft as the ball race. So, we need to confirm that your crankshaft is like the one in the diagram I've shown in this post, with a step down in diameter from 25 mm where the ball race fits on it, to 21 mm where the oil seal runs on it.

The parts list and the manual could both be correct if there had been a running change in the engine design, making the crankshaft diameter a constant 25 mm, and deleting the step down to 21 mm shown in the workshop manual. Workshop manuals are often not updated when that kind of thing happens. The problem we have is that if your engine is the original 21 mm version, it may be difficult to get an oil seal for it. 21x41x6 is not a standard size for oil seals.

Of course one possibility here is that someone in Honda's Department of Cost Saving Ideas That Only Screw Up the Product a Little Bit, found that the recess in the top of the crankcase casting that the oil seal presses into, was just about deep enough for the oil seal's lip to reach onto the 25 mm diameter part of the crankshaft. They could then substitute the 25x41x6 seal for the original 21x41x6 seal, and warn their dealers to be sure and always press the seals in as deeply as possible, because if they didn't, the points compartment would fill with oil and the engine would stop.

Please come back to us with a picture of the top part of the crankshaft, and those two diameters.