johnson 8hp

[Joben]

Hi all
I have a Johnson 2 stroke engine, 8hp, quite old. I amnot sure of the year as I bought it 2nd hand. Unfortunately the impeller gave up yesterday as I was going flat out. By the time I realised and stopped the engine, it was too late. There was a fair bit of smoke and a horrible smell of burning (to me, it smelled like burning electrics). I have taken it all apart today: indeed, the impeller was done (only 8 months old!). The plugs both have a spark and there seems to be compression in both cylinders. The smell is still there and it reminds me of my old scalextric cars when they burnt out when I was a kid. Does anybody know what else I should be checking? obviously the impeller needs changing but if the engine won't start, there is something else too. Thanks a lot

[a64pilot]

Does it have a reed valve? Also maybe the crankcase seal, assuming you can't get it to start and run well as that requires complete dis-assembly.Cylinder head for warpage maybe and the head gasket?
I'd first see if it runs OK before I started taking it apart.


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[Joben]

Originally Posted by a64pilot

Does it have a reed valve? Also maybe the crankcase seal, assuming you can't get it to start and run well as that requires complete dis-assembly.Cylinder head for warpage maybe and the head gasket?
I'd first see if it runs OK before I started taking it apart.


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doesn't run at all. I figure the pistons may be damaged, I'm not sure how long it ran without cooling, max 2 mins. I will look at reed valve tomorrow