the perils of evilbay!!! another engine needed

[ericcs]

IMG_0237.jpg
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pistons 1(10psi) and 2(still 120psi)at from my 2003 yamaha 90 2st(both bores are heavily scoured)
i bought the engine about 3 months ago, but have have only used it twice. it was advertized for 4.5k, amd looked as new. ended up giving my yamaha 70 2st plus 2.5k.
this is what happened after 3hrs run time, so the privelege cost me 1.5k/hr.
cruising across moreton bay last sunday, the motor started to slow down to an idle, then take off again. the symptoms suggested a fuel blockage as it never missfired, made no unusual noises and was pumping heaps of water. did this several times bunny hopping back to wello, eventually stopping dead in the middle of nowhere. took off the cowling, everything looked normal, powerhead heat felt normal. i tried to restart it, it made horrible noises so i shut it down and got towed in
it appears the warning buzzer, light in the tacho or the limp home mode don't work either. my theory is the oil pump failed, but can't check it unless the engines running i guess. it was running fine and the fuel is only a couple of weeks old, so can't think what else it could be.
so now i need another engine, and will need to take the punt on another second one, as the yamaha will probably cost 4k minimum to repair, so will probably part it out.
is anyone out there selling a reliable post 2000 long shaft 90hp?

[MudRiverDan]

Looks like they are the wrong size, pistons expand with heat.
Common problem with buying of EBay, needle in a haystack to match your pistons reliably down to a thou.

I know nothin of boats but have seen this in Commie engines with online pistons many times.

If you bought the whole engine, maybe a patch up and sell job, very shonky.

Dan

[cormorant]

Hmmm I wonder if the alarm circuit has been fiddled or just failed? Is there a special way to bleed out a yammi oil system when installing? What a expensive disappointment. Import a powerhead for it?

[Feral]

Ah the perils of second hand boat engines.
I reckon everyone my father ever bought (and its been quite a few) was more suitable as an anchor than a propulsion unit.

Always told myself I would only ever buy new.

[TREVELLY]

Sorry to read about mate - that's terrible - makes my little stone arriving instead of fishing reel on ebay seem like nothing.

Probably too long a shot to have it disputed as not as described and not fit for purpose item (ie working motor) - you could investigate small claims tribunal for being sold a dud motor but then you have the hassle of proving it was their fault and not yours - another pain.

Buying new is far superior but at a cost too and even then with greatly reduced risks still they exist ie 140hp Suzuki put on back of Roscoe's glass cat, but atleast it was sent back for replacement after a fight and getting the bank to stop payment.

Best bet if possible is to test run the motor for some hours before parting with the money - ie pay a deposit and agreement to pay in full if the thing works after three or fours hours running on the back of your boat - taking the seller along for the test run, so they can row the boat if it fails!

[bf90]

I used to have a 70 johnno 2 banger, it did the same thing as your yam, my problem was caused by a partial blockage in 2 of the carbys thus not allowing the correct oil/fuel mixture in and my pistons looked exactly the same as yours. All the motors are mate is a bloody big lawn mower donk strip it down ya self, get the block bored out and go get some new genuine goodies to put the motor back into service again . I did this with my johnno from memory it was about $700 in parts and the block boring, all else was just my time. I changed my motoer from oil injection to pre mix and never looked back again. Cheers.

[ozscott]

Sorry to hear that mate. More broadly I have had several fantastic second hand motors but always inspected and tested first or dealer sold. Cheers

[mustang5]

Sounds like she went short on Fuel as you described. No fuel = no lubrication.

Same thing happened to my Yam 200hp a few years back. Check the top of the piston on the outer perimeter. If it looks all banged up, fuel shortage/detonation is the cause, due to a blocked carb.

Given the age and hours of the motor, Im not sure you can put it down to a dud sale unless it is proven otherwise.. Question to ask is what sort of filter setup do you have running to the motors? When was it last serviced?

[Bros]

It doesn't matter weather it is Evil bay or just a second hand motor from a dealer it is all the same. Many years ago I sold a boat with a 40 hp black anchor to a bloke I knew but didn't see regularly. I saw him about a year after I sold it to him and asked how it was going. He said after 3 mths it blew a hole in the piston and I believed I sold it in perfect condition.

[ericcs]

mud river dan - could very well have been a patch up job, as the bloke had a dozen different motors in different states of repair. the picture of no.3 piston has it looking very new, you would think there would've been some light wear marksAttachment 85456

corrmorant - it would be handy to know of a way of staticly checking the oil pump. i'll check the price of a new powerhead, but the potential cost of a new oil pump and the fix or replacement of the alarm circuit may be just too expensive

trevally - the fellow i bought it off wasn't concerned whether i bought it or not and said i could bale out of the deal if i had any concerns, so i took it he wasn't trying to sell a dud asap, and being a clean 2003 with a good reputation i thought i was pretty safe, and it had 120psi in each pot. unfortunately i didn't get to use the boat properly for about 3 months, so i can't prove i didn't cause the problem. i would dearly love a new engine, but thats beyond reach now, so it will be another risk again

bf90/mustang5 - you both could be right on the fuel theory, as it wouldn't rev past 5200rpm spinning a 15'k prop on a 5m quinnie. it was pumping oil initially as the tank was full at the start of it's first voyage, but don't know if it used oil on it's second fatefull voyage. it was never revving much above 4000rpm on the day

[ericcs]

It doesn't matter weather it is Evil bay or just a second hand motor from a dealer it is all the same. Many years ago I sold a boat with a 40 hp black anchor to a bloke I knew but didn't see regularly. I saw him about a year after I sold it to him and asked how it was going. He said after 3 mths it blew a hole in the piston and I believed I sold it in perfect condition.

i understand where your coming from, as i will have to buy second again and put my trust in someone who may not offer any warranty. unfortunately, as you would know, with ebay you more often than not commit you take the punt and buy sight unseen thanks to distance etc.

[Fed]

You'd think if was an oiling problem all 3 would be scored.

[cormorant]

Is the scoring the same all around the piston? What is it like on the inlet side compared to the exhaust? Measure the bore up closely as this may be the result of someone doing a repair already- do all the pistons look exactly the same- like original - same part numbers ?

[Spaniard_King]

Just about to trade in a 90 merc 170 hrs or there abouts... pm me if you are keen it's very tidy and genuine

2007 Imaculate

[ericcs]

You'd think if was an oiling problem all 3 would be scored.

on 2 strokes, an amount of unburn't oil drains to the bottom of the crankcase, which is normally sucked up under vacuum thru a hose and fed up to the top bearing to dribble down again. my theory was that the middle and bottom pistons survived a bit longer because off the extra bit of oil