Older Engines

[malcolm]

I am looking for my first boat, second hand market, I have seen a boat which suits, however I have concerns over a 10yr old Yamaha 80hp with unknown hours, however is deemed "reliable"

Any thoughts?

Malcolm

[gavin]

When you buy a car older ones can be less reliable high milers etc, but how much work does a marine engine do , we do a lot approx 200 hrs a year, that means 4 hrs a week winter and summer.Whats the average 3 hrs a week for six months of the year? I dont know. However a marine engine on a boat used for leisure is only going to notch up a few hours a year and if its looked after well it is going to last.What I would say to you is its not necessarly about age, but condition, my first engine was 18 years old I remember myself and Tim bolted it onto a J24 and ran it for 9 hours continious crossing the Irish Sea, of course its better to buy newer if you can and try to find an engine with few years on it and preffebly few hours, but try to put a figure on what the engine might have done if used 6 months of the year for 3-4 hrs a week , would it have done a 1000 hrs, before you buy it you could simply screw a compression tester into the cyls and check for compression strength and what it should be.If an older motor has been looked after and serviced regularly , and a good make like a Yam, I wouldnt necessarly be worried about its age base your decision on its condition, its current state of repair, is there any indications of service, new plugs marks around the gear oil drain bolt etc etc service details or reciepts I wouldnt rule out an old motor if it has been looked after gavin

[Bilge Rat]

Agree with Gavin on this one, its the history of the engine that matters, i've found this out the hard way as i bought my first boat earlier this year and although the engine was spotless and ran like a dream i've had nothing but problems with it until finally it dropped 30 psi on one cylinder.

The engine has been stripped down and pistons and block removed and it seems that there's been an oil starvation problem at some time, whats worse is that its happened before as both cylinders have already been rebored out to maximum, so the block and new pistons have been sent off to an engineer to be resleeved and then rebored out correctly, i'm also switching to a straight fuel pump and going over to premixing my fuel as we think the same problem has happend before and the faulty oil/fuel pump were replaced thus correcting the symptoms but not correcting the initial fault.

Please dont be put off by my experience Yams are very good engines and you might be ok especially if you know the complete history of the engine, if the owner does not mind take along a compression tester and make sure both cylinders are the same, if you can get a sea trial ask for one, i didn't and now i know i should have, or even if you have someone you can take who's mechanically minded take them along as well, i was impressed at how clean for its agemy engine was when i bought it, and when my mechanice took it apart he said the water jacket was very clean and he'd have expected to at least see some deposits in it at its age, we now know that the engine has been apart before and thats why it looks so clean !!!

Good luck and let us know how you get on.

Richard

[Matt]

Spares can be more difficult, and therefore more expensive to obtain for older engines. But other than that, if an engine has low and hours and is well maintained, it's a good shot.

[robineff]

My Tornado 5.1 acquired back in the summer in very forlorn condition also carries a Yam 80 (AETO model - expect it's the same as yours) which was actually seized! Copious Duck Oil squirted into the pots and a large socket plus 2' wrench applied to crank end by local engine wizards L&J Marine, New Milton, Hants just moved it, and we gently manipulated it back and forth in ever increasing arcs. This sounded very dry and painful as obviously, we couldn't get any lube into the bottom end until the motor was spinning fast enough to open up the reeds and admit the oil. With a new battery plus a booster unit we got it turning over enough to squirt even more Duck Oil into the carbs until it seemed that the lube was reaching the journals and big ends.
After cleaning out the carbs, adding a new fuel filter (the bowl on the old one had actually rusted through!) and fresh fuel it settled down to run as sweet as a nut.
All this fearsome abuse would seem to indicate that they're very well built, and although we haven't done a lot of hours yet, there would seem to be grounds for confidence.
The main snag with these older carburated 2 strokes is their thirst, which is firmly in the George Best league! Apparently, at full chat, they're rated at 8 gallons an hour (mops brow) but there again, full chat isn't something you often need.
A tip that L&J passed on: When manouvering onto moorings/trailer at low revs, the oil injection ratio is very weak and if you just switch off when secured, there is very little oil remaining in the bottom end. Answer - select neutral and rev its tits off on the hand throttle before cutting the sparks at high revs. Spooling down from high revs with no combustion will leave plenty of lube over the sensitive bits, especially important if you're not planning to use it for a while.
And another thing - they're lightweight and power:weight ratio is very good.

Robin

[jwalker]

Originally posted by robineff
...which was actually seized! Copious Duck Oil squirted into the pots and a large socket plus 2' wrench applied to crank end by local engine wizards L&J Marine, New Milton, Hants just moved it, and we gently manipulated it back and forth in ever increasing arcs. This sounded very dry and painful ............

Robin

Fkin botchers.


............and power:weight ratio is very good.

That's 'cos some of the aluminium from your pistons went down the exhaust port.