1987 120hp question

[weezzell_5400]

Got a 1987 120hp v4..model number E120TXCUR ........has low compression so I figured I would check the easy things first ....head gaskets ....and they were fine also checked for stuck rings ...nope...so now new rings and pistons are in the near future ...was wondering if anyone could tell me the specs on the cylinder bore on the motor.....what is out of specs....I need to buy a service manual...just ain't ready to drop $50 just yet until I find out the engine is worth saving ....thanks

 

[jbuote]

I don't have any answers for you, but this might be helpful... Mixed reviews on these manuals, and accuracy of some of the specs for some years etc, but could be a starting point for you.

http://boatinfo.no/lib/evinrude/manuals/1973-1991johnsonevinrude.html#/0

Definitely best to buy an OEM manual specific to the year, but in the meantime, you may find SOME of your answers, and maybe help decide on getting the right manual.. At least until the real experts here have a chance to weigh in..

​For what it's worth...

 

[Faztbullet]

You have the small bore looper with bridged exhaust. Std bore is 3.500 and anything above 3.503 needs bored. The replacement pistons will need to have cooling oil for bridge drilled and bridge modification.

 

[weezzell_5400]

What do you mean by the pistons need to be drilled ....never heard of this

 

[Faztbullet]

OEM pistons has hole drilled in them on the exhaust side to provide extra cooling/lubrication to bridge to keep bridge from scuffing piston, replacement piston don't.

 

[weezzell_5400]

Thanks so much for the info....was looking at the rebuild kids for this engine...and the ones found on eBay come with wsm pistons.....are these pistons and rings any good....not really heard of them before....was looking for what's best for this application...thanks

 

[Faztbullet]

That all I sell is WSM........110% good quality parts. Take pistons to machine shop as drilling is not a DIY project

 

[weezzell_5400]

Thanks....and I wouldn't dare attempt to do something such as that in my shop....thanks for all the advice...