Hello, I have a very old 7.5 hp four stroke. It is a long shaft unit s/n BF751003082. The motor wasnt cooling properly (no pee hole water). I have taken the lower unit off and sure enough the impeller is toast and needs to be replaced. My problem is that I can not seperate the longer drive shaft from the lower pinion shaft to access the impeller. I have pounded on it, used a tourch to heat the drive shaft near to the impeller housing, yet I cannot seperate the two shaft assemblies. Anyone have an suggestions?

Thanks

Only had one of those that couldn't get apart and ended up cutting shaft into and installing new shaft so keep soaking with oil and hopefully can break it loose.

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Honda Outboard Parts

Thanks for the feedback. Still it is frozen and not able to separate. At this point I am starting to deform the impeller housing (metal cup insert) and still can not separate the two shafts. Parts are too expensive to cut shafts and replace too many parts unless I can find them used. The engine still runs pretty good, but it is over 30 years old. Maybe I part out what remains and sell it here or on eBay.

My first Honda project was a B75 (white one) about '75 or '76, and it had the plated carbon steel shafts probably like yours, before they switched to stainless steel shafts. I set out to replace the impeller, but like you, tried hammer, torch, PB blaster spray, etc. etc. and it wouldn't come apart. Since the impeller was worn but not broken, I decided it was ok after all and put it back together! Unfortunately you don't have that option though.
I would try more of the same.
Good luck.

Thanks Honda John....yep I also have tried PB Blaster, Liquid Wrench, and the rest of the stuff hammer, etc. It still will not separate between the 2 shafts.


I found a lower unit on eBay and have that coming. It was costly but less than a new engine, so hopefully I can salvage what I have.

I do appreciate the info though....BTW, my engine is the older white one with points.