Logo
FULL SITE MENU

Mariner 1997 40 hp (4 Cyl) needs rebuild; Newbie needs good advice.

M

mmonte

New member
Hello to all,

Yes I'm a newbie, and yes, I've used the search function.

I have a '97 Mariner 40 HP (4-Cyl, #0G537601) that has the following compression readings: 135-135-30-135. Looks like I need a rebuild.

I have been informed by 2 of my local boat shops that finding a powerhead for this 4-cyl model is difficult. Apparently, the 4 Cyl models are not as common as the 3-Cyl models and no one they have contacted, nor a google search of my own, has produced a powerhead in stock at a reasonable price.

My questions are as follows: Is this a good engine that is worth rebuilding? What is a ballpark amount of money that I should spend to get this rebuilt? Am I better off procuring a used engine from ebay/craigslist and installing that instead?

Any and all comments, suggestions, and advice is welcome.

Thanks in advance!
 
Re: Mariner 40 (4 Cyl) needs rebuild; Newbie needs good advice.

This is an excellent powerhead - and a very rebuildable motor and one I would love to have.

Depending on the damage you probably don't need a new powerhead. A reputable machine shop can bore out the bad cylinder (normally about 50 bucks a hole).

If you are looking for a shop to rebuild count on $1500-2500 depending on what needs replacing.

If you are even slightly mechanically inclined you can do much of the work yourself. Even using the services of a machine shop I can generally rebuild a 3 or 4 cylinder myself for under 1000 bucks (including all the pistons, rings, gaskets, seals, bearings etc).

I would personally have all the cylinders done - at least honed if they didn't need a bore, and at minimum replace all the rings and bearings - the biggest cost/hassle is "cracking" the block so may as well do all the "guts" while you are in there.

Also, don't forget that the initial problem that caused the toasted cylinder needs to be corrected as well - number one culprit for a single cylinder failure would be a clogged carb.

So count on carb rebuilds as well - 200 bucks for the first carb, and 150 for each subsequent. Those are not "included" in a rebuild.

Swapping it for another used engine could leave you in the same situation. Whenever I buy a used motor I assume it will require a rebuild in the very near future.

NOBODY sells an outboard that is "perfect" or "runs great" - if it was as they describe they wouldn't be selling it.

However, given this horsepower you have to compare the repair costs to new. It could run you 3K for a total rebuild/refurb - a new 40 (either 4 stroke or direct injected 2) can be found for under 5K.

If you can't do the work yourself I would be inclined to either "buy new" or roll the dice with another used motor....
 
Re: Mariner 40 (4 Cyl) needs rebuild; Newbie needs good advice.

Thank you "galamb" for all your advice: this was exactly what I was looking for. It was especially helpful to hear that my particular engine was one that was actually worth rebuilding. Am I wrong in believing that it was manufactured in Japan? Possibly by Yamaha? I would love to find out.

Turns out that I am very mechanically inclined and that I have always wanted to rebuild an engine, so I have decided to make this project my first engine rebuild. I guess this is where the next set of questions begins:

I found the following link on e-bay:
http://cgi.ebay.com/ebaymotors/POWE...at_Parts_Accessories_Gear&hash=item5884938aeb
Is this the kind of kit I need to get? If not, can you recommend a good parts supplier for a rebuild kit and for the carburetor rebuild kits that I will need?

Thanks again,

Monte
 
Re: Mariner 40 (4 Cyl) needs rebuild; Newbie needs good advice.

Many Merc models, prior to 2005 were build using parts that Yamaha specifically made for Merc.

Aside from the Yamaha/Mariner line which was totally Yami and copies of their own branded motors, Yamaha built powerheads for Merc that they never used in their own models (most notably the "headless" powerheads such as yours).

So while your power head and gears were built by Yami, they were built specifically for Merc and never saw service on a Yamaha.

The ignition and fuel system is pure Merc as is the gear case.

So while Yamaha significantly "contributed" to this model, it really is "all Merc" in design...

And yes, the kit you found on Ebay is the "homebuilders" kit in a box.

That gives you a good estimated cost for a home rebuild. You would have to add about 200 bucks for machine work (bore or hone) and maybe another 200 for carb kits and extras.

So for about 1000 bucks you can end up with a "totally" reconditioned powerhead that could easily last you another 20 years..

If you are going to undertake this yourself I would really spend the 80 bucks (or so) and get a factory service manual for your motor - merc part # 90-814676R1 - will detail every aspect of the rebuild specifically to your model - much more precise than a (wide ranging) Seloc's manual...
 
Re: Mariner 40 (4 Cyl) needs rebuild; Newbie needs good advice.

Monte,

By The serial number you are suppling that motor is all Mercury and has been for 40 years other than piston design changes and ignition updates added oil injection etc... the exhaust ports are pulled .050 in comparion to pre 91 model. So Yamaha made the parts in the powerhead. I have talked to the casting plant in the US a few times about molds and blocks for that motor and they were all destroyed including 100 or so new blocks about two years ago now if I recall.

I build those powerheads all the time we use them for Racing in APBA and CBF the racing counterpart to that motor was a 44xs built from 87-90ish. Boring and Honing I do in-house as well.

galamb is right they are probably one of the most dependable and long-lasting motors Merc ever built. I have lots of parts for those engines from 1955 to 1995.
 
Back
Top