2.5 ff rebuild

**Merc 2.5** · 09-30-2018, 06:29 PM

So far crank is rotating very smooth ea time a piston goes in, sealing r staying in place and not dragging around. I being paranoid with ring compressor and rings on the pins correct, I keep quad druple checkin (spellin?)

**Merc 2.5** · 09-30-2018, 06:35 PM

Nope left that alone , If i ever rebuild it again i may do slots and heavier porting, but since this is my 1st complete build , i wanted keep it on mild side. Plus my bote wouldn't handle all of what the 2.4 had , So I know this one gonna be nite and day from the 2.4, when this motor is broke in and doin gud . I'll be over on the 20ft under section tryin find a stream!!

**Merc 2.5** · 09-30-2018, 06:38 PM

As far as I can tell ,if u buy a new set rings for used pistons then may have to file or sumthin ,idk but all these r great, plus James is the man and we know the bores r dead on!

**Merc 2.5** · 09-30-2018, 08:05 PM

Well here's a pic with 5 new slugs in, I have a questionable rod so on have 5 in, should have another rod here prob Wednesday, has a micro size chip on bearingsurface.. I do have a engine stand but its loaned out and Hes out town workin. So I have been building it on a stainless bench

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**Merc 2.5** · 09-30-2018, 08:09 PM

One thing I didnt do was go light on the oil! When it says oil lightly most time I let it have it , including soaking bearings, it wont b started for Couple weeks and I know they love the oil

**Baker343** · 09-30-2018, 08:49 PM

Originally Posted by Merclover

One thing I didnt do was go light on the oil! When it says oil lightly most time I let it have it , including soaking bearings, it wont b started for Couple weeks and I know they love the oil

Enjoying the read

**NeedOne** · 10-01-2018, 07:57 AM

Subscribed.. thanks for posting, def gonna be a good reference for some of those stray details that dont make it in the maunal

**bbezok** · 10-01-2018, 11:35 AM

[QUOTE=Merclover;3080108]One thing I didnt do was go light on the oil! When it says oil lightly most time I let it have it , including soaking bearings, it wont b started for Couple weeks and I know they love the oil[/QUOTE
Following your progress daily, will soon be doing a 2.5L build and currently on the fence as to trying it myself or having someone with experience do the long block.
keep the posts coming.

**Merc 2.5** · 10-01-2018, 11:41 AM

I am mechanically inclined, i dont wanna speak to soon but to me I knew if I did my homework and talked to the "right" people I could do it. Take your sweet time and if you catch yourself starting to rush, then just stop and take a break for min. Count everything 3 times,and have a merc manual either pdf on ur phone or a book beside ya. And clean clean clean

**bbezok** · 10-01-2018, 11:53 AM

Same here, have built several car engines and even a tranny or two over the years, most recently restored a 1970 Dodge Challenger to factory specs but never touched anything that was 2-stroke before so not being real familiarwith them, it's a bit intimidating.
Have to say though, there is such a wealth of knowledge on this forum and the willingness of members to take the time to share their views and information is truly priceless.

**Merc 2.5** · 10-01-2018, 12:01 PM

Yep I agree. If it weren't for this site and the awesome guys with TONS knowledge, I wouldn't be doin it , I'd prolly bought another half wore out motor. My rod should be here wed and I'll be able to continue the build. I love to read a successful rebuild thread from start to finish , unfortunately most threads stop half way or so .. good or bad this thread will be updated til its finished and hopefully running. (Praying lol)

**rock** · 10-01-2018, 12:46 PM

I highly recommend anyone with even a bit of mechanical aptitude that is into boating give it a shot. Knowing what is in there and what is going on can be very beneficial. Especially when you start trying to diagnose an issue. Its not rocket science.

Rock

**Merc 2.5** · 10-01-2018, 06:19 PM

Originally Posted by texasvector

thats how ive done mine...never filed a damn thing

any rod slot work?

Ok so he we go. I did a little back tracking when I got in from work. I ended up pulling slugs back out and checking ring gap, I know there is alot of controversy about this subject and I started not to post it ,but for those who are tryin this for 1st time ,would prolly like to know. With a bore of 015 over I end up with a gap average 022. If I'm not mistaken this gap # would be less on std bore? More on larger bore? But these numbers all check in spec for a steel sleeve and cast piston.(non forged) ,according to merc , nic cyl and forged pistons will have a different gap setting?, different clearances ,So I feel I'm good to proceed with the build.

**Merc 2.5** · 10-01-2018, 06:35 PM

Originally Posted by Baker343

Enjoying the read

Hope you kill it at the enduro, is yours going back together or back together?

**wrechin2** · 10-01-2018, 07:17 PM

Originally Posted by Merclover

Ok so he we go. I did a little back tracking when I got in from work. I ended up pulling slugs back out and checking ring gap, I know there is alot of controversy about this subject and I started not to post it ,but for those who are tryin this for 1st time ,would prolly like to know. With a bore of 015 over I end up with a gap average 022. If I'm not mistaken this gap # would be less on std bore? More on larger bore? But these numbers all check in spec for a steel sleeve and cast piston.(non forged) ,according to merc , nic cyl and forged pistons will have a different gap setting?, different clearances ,So I feel I'm good to proceed with the build.

The ring gap spec is .018 to .025 for that engine. Because of how I ported it, I added a smidge more clearance (.0005) for expansion due to heat. Having an average of .022 you fall in the middle and have a nice tight engine with very minimum leakage due to small ring gap. Ring gap will be the same in std, .015 or .030 bore as the rings are made for that size cylinder. Put it together and have fun with it. Just my .02