Can anyone advise what is likely to go wrong with a small (12 HP Petter) which has been lef alone for 12 months while the yacht has been laid up. I am somewhat chary of buying a boat and finding that the engine is kaput - but don't know of any quick way of checking (without employing an engineer).


Not meaning to be facetious - but try starting it. - If the boat is afloat then it would be quite reasonable to ask the vendor or broker for a demo, if ashore it should be possible to rig up a hose to the water intake to permit the engine to be run, although you may have to provide your own battery if the one on board is flat .

Petters being made in a mix of ferrous and light alloy are notorious for corrosion problems and you may well find it has seized, the common problem being a build up of corrosion between the cast iron flywheel and the alloy casing.

IMHO - not the worlds best engine,and getting on a bit now - think twice before buying.

hope this helps, rob.


There really isn't much that can go wrong with a small diesel engine, unless it wasn't properly prepped for non-use.
It would depend on if the boat was in the water or on the hard. If it was to be left up intentionally it should have had the
fuel filters emptied, the oil changed and probably would have been a good idea to drain the fuel tank, or at least
had a biocide put in the fuel to keep it from growing microbes that would later lead to problems.

If it was left in the water...the seacock should have been closed and the seawater strainer cleaned out.

I bought my present boat last November...the owner had done virtually nothing to the Perkins 4-108 to prep it for storage
on the hard..... but when we splashed her....we turned the engine over and it started right away.

You should be able to feed a waterhose into the raw water intake and crank the engine...that way you won't have any question
about whether or not the engine will run. Just don't rev it up .....give it a few minutes of idling to let it coat all
the moving parts that are very dry.


Well-known member
15 Jun 2001
Haslemere/ Leros
Check the Oil

Check the colour of the oil - if it was laid up OK it will e relative golden in colour.
Old oil in a diesel is suprisingly corrosive. If they didn't bother to do this then what else didn't they bother with???

Again with the Peter - check that the anode has been changed, as these are notorius corrosion machines.

Not one of the worlds best marine engines!!


most petter engines are fully re-buildable and spares readily available (see other post in this forum)

I'm running a "mini-twin" or AC2 W (14hp) which I guess may be similar to yours? It was also left standing for a considerable length of time....

OK - the nitty gritty:
1. Fuel filter gets clogged quickly and is a real beggar to change (My current project is to replace it with a CAV canister type unit with separator)
2. Our fuel lifter pump gave up ("experts" said that they never expire, but ours did at a cost of about £70)
3. Cold starting is difficult - we keep a can of easy start in the boat. Sorry, I know it's evil stuff!
4. Our dual function water pump (raw/fresh water0 gave up and needed new impellors.
5. Yes some of the ancilary components do corrode (esp the hi-pressure fuel lines)
6. Shakes the engine mounting bolts loose!
7. Temperature all over the place!

Good luck...




Don't forget to prime the cylinder head with engine oil, or she probably won't start (Ours wont!)