Powerhead assembly - piston pins - are tight

[Fl_Richard]

Just beginning re-assembly of my 150 -1995 engine. Have all new pistons and bearings, I'm removing the piston pins from the two scored pistons and they are tight. I pulled them out ; they are tight in the new pistons but they will fit. Probably wont spin in the piston.

Do I need to replace these two pins or is tight OK?

Thanks
Richard

 

[daselbee]

Re: Powerhead assembly - piston pins - are tight

Just wondering?

What brand of pistons and bearings did you select?
I am beginning a rebuild of a 1996 V6 200, and I need to know the best parts source.
Thanks

 

[Fl_Richard]

Re: Powerhead assembly - piston pins - are tight

I used OEM pistons - .020 over, rings and bearings. Everyone says you cant get OEM in .020 but their wrong. I have the boxes to prove it. I used boats.net for most parts. Their prices are ok.... not great but ok. I've had some bad luck with actually getting parts from the e'cheepo sites.

 

[fixmyevinrude]

Re: Powerhead assembly - piston pins - are tight

I rebuilt a 1994 200hp Evinrude last fall and bought all my parts from Pro Marine.I believe they are in Florida. Parts came when promised and all worked out well. By the way the pistons came with the wrist pins and clips and they were a perfect slip fit. The OEM pistons and wrist pins I replaced were a light press fit. Someone last fall had a simalar concern about wrist pin to piston fit being a slip fit and I believe it was Dhadley who answered that the paticular piston company he was referring to had spent a huge amount of money on a machine to produce that perfect fit.

 

[F_R]

Re: Powerhead assembly - piston pins - are tight

I can't say for sure about the engine in question, but historically OMC pistons and pins were slip fit in one side and press fit in the other side. The slip fit side is marked with an "L" or something similar. You remove the pin by pressing it all the way through the tight side, and install the new one by going through the loose side first, into the tight side. Doing it the wrong way distorts the piston.

The idea behind the one loose side is that the piston can expand/contract/slide back and forth on the loose end of the pin.

 

[mrimike]

Re: Powerhead assembly - piston pins - are tight

i have rebuilt dozens of bombardier seadoo engines and every one was tight from the factory. Most would slide in easier with wd40 and a propane torch to warm the piston and keep the pin in the fridge..
brp makes evinrude-seadoo stuff..'
you will be fine..
You DO NOT want it loose..
If need be use a piston pin puller.

 

[F_R]

Re: Powerhead assembly - piston pins - are tight

OK, I just checked a 1989 V-6 service manual and the pistons no longer have the "loose" end. They do, however specify using a cradle to support the piston from distortion while pressing the pin in.

Anything newer than 1980 is a new motor to me. Anyhoo, to prove I'm not nuts, this is from 1972

 

[mrimike]

Re: Powerhead assembly - piston pins - are tight

wow thanks fr that is interesting that they used to do em like that..... that was before i was even born! Learn something everyday

 

[Dhadley]

Re: Powerhead assembly - piston pins - are tight

The OE pistons are a slip fit. I don't think anyone used a "press fit, one side" piston anymore, even to replace the ones that were originally. It'll be fine, just kind of odd it didn't come with a new pin.