Rebuilding sons 25 hp 2002 merc 2 stroke

**XstreamVking** · 07-10-2017, 06:21 PM

As said doing a rebuild, anyone used kits from PWC engines? They use wiseco pistons and rik rings supposed to be good according to them. I am leaning toward getting merc parts, son is thinking this place.... What's the good stuff? I don't care if it costs more for the merc stuff me self....Any one with any experience? https://www.amazon.com/dp/B01C1QWU3K...aa957041a1fd_S

**FMP** · 07-10-2017, 06:45 PM

Been wondering myself, chrome bore?

**XstreamVking** · 07-10-2017, 06:57 PM

Has a sleeve, so I don't believe so. I was wondering about the x-tra clearance with the wiseco's since the v-6 motors using wiseco's need more than a stock piston does. Sucks a merc new p-head is nla.....

**rock** · 07-10-2017, 08:36 PM

Not sure about year to year changes but at least some of the 25s are Mercasil. My understanding is it is comparable to Nicasil.

Rock

**XstreamVking** · 07-11-2017, 07:12 AM

Rock your right. Did a little digging and it is a mercasil bore. No sleeve! I'm thinking that a new block and stock pistons etc would be better than boring and going oversize..Prob fairly close in cost also. It's been a great motor and has thousands of hours on it....Just worn out. Son has had it since new. He is def keeping it going since it is the perfect motor for his 13' homemade tunnel. Might start tearing it down this wknd for inspection.

**FMP** · 07-11-2017, 07:33 AM

That's what I thought. Have two , one with years of hard hrs. Still strong but down a bit in one cyl. No PH available, wiseco I like . Go a hair over the box size if worried. Sleeved??? What's psi on these 135?

**XstreamVking** · 07-11-2017, 07:43 AM

Our motor was 125+ when newer. Now it's 110 psi. Didn't do leakdown, i'm sure it's high. ... Lost speed but still runs good. No sleeve. Cylinders coated with mercasil. And mixed results when bored from what I have read... We just bought a 2nd motor cheap for some x-tra parts, it's knocking so it has a con rod issue? Prev owner says it was bored and re-built and never performed as good as original then started knocking and was taken off. Don't know what parts were used.

**FMP** · 07-11-2017, 07:44 AM

Check other thread , just ttt you.

**W2F a V-King** · 07-11-2017, 08:14 AM

Originally Posted by XstreamVking

Our motor was 125+ when newer. Now it's 110 psi. Didn't do leakdown, i'm sure it's high. ... Lost speed but still runs good. No sleeve. Cylinders coated with mercasil. And mixed results when bored from what I have read... We just bought a 2nd motor cheap for some x-tra parts, it's knocking so it has a con rod issue? Prev owner says it was bored and re-built and never performed as good as original then started knocking and was taken off. Don't know what parts were used.

The difference in performance is likely the bored and re sleeved motor has a steel bore now vs the OE mercasil bore. Big difference in friction between the two. And likely more noticeable on a smaller hp motor.