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Rebuilding 1990 Johnson GT175 - Problem?

S

stratos285

New member
I'm rebuilding at 1990 Johnson GT175. Have installed the new pistons and attached the connecting rods to the crank but have not but the case together yet. When I turn the crankshaft, the pistons or connecting rods "pop" when they get to full stroke. Is this a problem or is this because I have not joined the case halves together and stabilized the crankshaft. I do have it bolted at both ends with the top and bottom seal plates. The heads are not on. Have removed the crankshaft and made sure it was installed correctly with center main bearings in pins. :confused: Don't want to proceed if this is a problem......
 
All of the engines I've rebuilt (since 1960), the rotation of the crankshaft, and pistons thru their full cycle has been a smooth flow.

You say "the piston or connecting rods pop when they get to full stroke". Are these std pistons in a original std bore or new std sleeve OR oversize pistons in the original sleeves that have been bored oversize, OR a mixture of some kind. You need to state exactly what has been done to the crankcase (block).

At "full stroke", a piston will be at TDC.... BUT by the same token, a piston is bound to be at the bottom of the sleeve. If an original sleeve was bored oversize and done improperly, the boring may have left a small section as standard bore which the oversize piston would be running into a ridge or sorts.

I don't know what you mean exactly by "pop" but if resistance of any kind is encountered, no that's not normal.
 
John,you should start your own thread.They don't like it when you hi-jack another peoples threads.
You have a stator which charges as you run.Include motor,HP,year,model etc.
Solor chargers:to charge a battery quick,you'd need a panel the size of your boat.J
 
Now to the original: The pistons fit with no binding?
The pistons installed right? My first one I installed them 180 out.
The pistons not hitting the table when extended?I did that too.
Like Joe says they shoud cycle without comming out.
 
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