anyone know Mercury outboards ?
 

I'm talking with a seller of a 17 ' Boston Whaler that has a 1986 Mercury 90 hp outboard. Supposedly recently serviced and runs well. This is a six cylinder two stroke with three carburetors. So other than checking compression what should I look for in this outboard ? I know Evinrude/Johnson fairly well but know nothing about Mercury other than they are black in color :D. Any experts out there ? I would think this engine would push that 17 ' hull quite well.

Good engines. I have a 1986 75 hp outboard that works wonderfully (been in the family since new). Just check the oil auto-feed system (I believe the 90 hp engine has the same system), compression and you should be good. The ignition controller can be problematic also but I think that's the only issues its ever had.

Remember nothing is inexpensive with outboards but I've had good luck with mine and would trust it to get me home regularly.

Basically a sound engine, easy to maintain and is reliable, lighter than the 4 stroke cheaper to maintain also. I owned a 2002 150hp salt water series 2 stroke with carbs for a few years, easy to put up for the winter, and had no issues with it. New spark plugs at the start of each season
use the top shelf Mercury 2 stroke oil and hitest gas 91 or 93 RON. Has this engine been all fresh water or some salt water or all salt water?
Dana.....

Similiar to Johnsin/Evinrude the grey Mercs have Mariners on the cover. I've had an '89 150 Magnum II (same as the Merc Black Max) since new....feed her NGK plugs and 93 octane (non-ethanol if available), and a 90 is more than enough for that combo...buddy had a similar setup years ago. Enjoy!

I am getting more details on the engine including fresh/salt water usage. Will chime back in when I know more.

I have the same engine on my Alumacraft Competitor. Tiller (I had it converted). The boat does 52 mph empty.

The power trim unit is expensive to replace. Luckily I horse traded boots for my new power trim when mine went.

If it runs good and the compression numbers add up there is not much else to check. Anything can go bad at any time and there is no way to tell when. They made a 70 hp, 80 hp and 90 hp engine in those series. My buddy had a 70 and upgraded the power head to a 90 when his 70 blew up.

I always think of Evinrude/Johnson as like GM/Ford, and Mercury as like MB.

that's a really old engine when you do the math of original year...........

Water is not kind on marine engines, with exhaust water jackets and aluminum parts and such.


Do you want to fish and crab and explore, or wrench?


Unless it's a screaming deal, I'd really shy away from something that old.

It's an old technology that is being replaced by newer direct injection ETEC two strokes and modern four strokes. They really aren't worth much anymore. We just pulled the trigger on replacing a 2000 era 115 HP Johnson, which is almost identical. It needed rebuilding. We got an ETEC instead. It's so much nicer. We could have bought a fully rebuilt one just like ours for less than a thousand dollars. It would have taken about that to rebuild it. The guy gave us $500 on a trade in.

Newer engines start with a turn of the key, don't pollute like the Exon Valdize, and are much quieter. No one wants the old two strokes anymore and with good reason.

Seller chimed in last night the motor is original to the boat and was run in freshwater only until last year. Last year had light usage in salt water. I've asked for compression numbers. Thanks to everyone for the feedback. Yes this is an old school outboard but I don't think they should be tossed into the trash heap. Yes a new outboard is superior but it's also $10,000.00 !!! That is NOT what I want.

Check the engine harness trust me on this.

Details please what specifically to look for ? Also the seller sent me more pics last night, boat looks good trailer looks good the outboard has some corrosion on the lower unit I assume from the saltwater usage. I will have to get better pics or inspect it when I go look at it. I have no problem if it is surface corrosion that can be sanded, primed and painted but if it's worse than that it may need a lower unit. It looks like the corrosion is from the spray plate down. I assume the sacrificial anode may be shot. More to follow.

Mine's only seen salt/brackish water a few times, and always cleaned/flushed good afterwards. Always kept inside too. Talking to a local boat guy (he was selling lots of boats on consignment, and business was great last summer), I was surprised at what he thought my rig would bring (maybe 8K), but his comment was "have you priced a new boat/motor lately?"....sometimes you don't need a Carrera rebuild when a Cheby will do just fine.

check for good water flow before running it too long. impellers can stiffen sitting too long. burned a new piston on an old merc I had just rebuilt the first time I took it out because I had forgot to change the impeller. cheap and easy to change.

Don't be afraid of salt. Sure beats being stuck in freshwater.

The motor is worth very little but if it runs well then enjoy it.

Flush fuel tank, replace fuel lines (and bulb) and battery, replace spark plugs, use non-ethanol fuel only and stabil. Next replace the bearings on the trailer and you're all set.

Your real concern on a boat that old is a solid transom.

+1 to the no ethanol fuel - it will eat the lines

Seller just sent more pics I specifically asked for shots of the engine/lower unit. Apparently his version of " some corrosion " and mine are quite different :( . The lower unit looked like a barnacle restaurant it was very corroded to the point that the thin ring by the prop was missing in spots ! :mad: Oh he forgot to mention the transom separation :rolleyes: . Didn't look real bad but was split on the top seam for about 3-4 inches so I have to assume water penetration. It can all be fixed but not at his asking price. I threw him a number that I doubt he'll accept but we'll see.

Boston Whaler people are like air cooled VW people in that regard.

Check for cracked wires going to the connections. I believe it also has a magneto (spelling) the outboard generator basically make sure the wires are in good condition.

Seller has not responded to my low ball offer I may have upset him :D. Oh well I'll just keep looking. Happy Thanksgiving SmileWavy