problems from not running eng. enough?

[Fishspearit]

I'm wondering what problems to look for/expect from a 10 year old yanmar engine that only has 20 hours on it. It's on a generator that was rarely used. At this point I don't know the service history of the engine. I was thinking maybe corrosion problems with the heat exchanger if stagnant water has been sitting, but what other sorts of things should I be looking for or expecting down the road? Or is this not that big of a deal?

[AnchorageGuy]

With a generator the engine is literally only half the problem. Aside from corrosion in every part of the engine including and especially the cylinder walls, expect problems with the stator, relays and just about anything else. You might get lucky and start and run it with minor problems down the road, but expect the best and plan for the worst. The worst being removal of the unit and a rebuild or replacement of some pretty expensive parts. Most all service problems we have are from generators that are seldom used.

[dcstrng]

I’m no professional wrench – barely a shade-tree one – But, besides the obvious water related concerns you alluded to (zincs and corrosion effected elbows, exchangers, manifolds, etc.), the adage on a little used motor (of any type) is to watch for hoses, belts and gaskets… especially hoses and belts seem to deteriorate (dry and lose elasticity) more based on the calendar during prolong disuse, than hours run (assuming normal usage – whatever that is…). The interior surfaces of the engine can be a concern as well, but usually not disastrously as long as when it is started, care is taken… Since the level of engine wear (bearings, valve guides, rings, etc., etc. – wearing surfaces) is the highest for about the first 5-10 minutes of running, a little used engine is almost always in the high wear cycle so may be worn beyond its 20 hour level, but not necessarily catastrophically so…

However, an engine with only 20 hors may still have its break-in oil, or likely hasn’t see fresh oil in some time – at least worth checking – and a fresh oil change would be the first order of business (inspect the old oil – especially for milky signs of water contamination…). Synthetic oils have a reputation for staying on the cylinder walls longer than dino oil over prolonged storage, but my guess is as little as this sounds like it was used, may not be a factor… plus, there is the usual challenge of degraded fuel and all the little micro-bugs that love to inhabit little-used tanks, lines and injectors…

Take `er easy... Good luck...

[hellosailor]

And rust, from condensate, freezing the piston rings to the cylinder walls. Could easily need new rings and cylinder lapping. Injectors may also need rebuilding/replacing.

The good news is that it should be rebuildable, or cleanable. The bad news is that of course you'll need to really look it over, and probably do a whole mess of work on it. Every time a standby genset is shut down--it should be pickled, but they rarely are.

If the price is right...<G>...

[Alan Wheeler]

It also depends on how the hrs were clocked up. If it was run for 20hrs 10yrs ago and has sat ever since, you may have problems with it. If it has had 2hrs of use each year, you may have winner.

[johneri1]

And the obvious: fresh fuel....

[Chief Engineer]

If the generator has been in a humid climate and not run, the shellac that is on the coils in the generator may be broken down. Shellac is a biological product and can be subject to attack from organisms which break down the insulation......This happened to me on a Genset that had not been run for 6 years......started up ok, after about 15 hours running.....blam.