Secondhand boat: How do you know if the diesel is OK?

[paulferris1964]

Thinking of trading up from my Hunter Duette (outboard) this winter to something bigger with an inboard diesel. However, limited funds for a 30 footer are likely to mean a 1970s or 80s boat. I can see the sense in picking one that has recently been re-engined, but how do you tell if the engine is OK, short of running it whilst at sea? Is it even possible?

Most boats will be in the yard and standard surveys don't look at the engine anyway, I believe. Do people instruct an engineer to give engines a once over? Can they be run on the hard with bucket and hose cooling and would that show anything worthwhile in any event?

Nervous about buying an old boat without much opportunity to test such an expensive part of it first, and any advice gratefully appreciated.

 

[Tranona]

Sensible to look for a re-engined boat. Try to get a good service history. Engines typically last for 30-40 years and give little trouble if they are properly installed and regularly maintained. You can get an engine specialist to check the installation over for you as part of the survey and make the purchase subject to a satisfactory engine trial, particularly if the boat is out of the water during the purchase. There is no foolproof way of guaranteeing the engine will be reliable and long lived, but if it starts immediately, does not smoke, runs smoothly and you can achieve maximum revs in gear, there is little wrong. Check externally for neat installation, no leaks from water or oil and good flow of cooling water.

 

[fisherman]

Sensible to look for a re-engined boat. Try to get a good service history. Engines typically last for 30-40 years and give little trouble if they are properly installed and regularly maintained. You can get an engine specialist to check the installation over for you as part of the survey and make the purchase subject to a satisfactory engine trial, particularly if the boat is out of the water during the purchase. There is no foolproof way of guaranteeing the engine will be reliable and long lived, but if it starts immediately, does not smoke, runs smoothly and you can achieve maximum revs in gear, there is little wrong. Check externally for neat installation, no leaks from water or oil and good flow of cooling water.

Best is to run on maximum load to full temp if possible. On the hard put the hose in the top of the seacock and close the valve, you can only follow#2.

 

[TQA]

Do you intend to buy the boat without a sea trial ?

Assuming it is on trial, insist that you see the engine being started from cold. Put your hand on the engine first to check if it is stone cold. It should start without anything being squirted into the aircleaner to 'help' it.

Run it for several minutes on trial at full throttle, look for excessive smoke, the water temp climbing [ some increase is ok ] and the oil pressure falling. When you go back to tickover check the oil pressure again again some drop is OK but it still should showing some reasonable pressure, my old Perkins drops from 40 psi to 20 psi when at tickover hot.

If it starts easily and passes the other tests then I would be happy. That is realistically all you can do without dismantling. Most owners will not let you do this. Even then a crank could be cracked or a water jacket almost corroded through.

Specific engines have specific weaknesses. Do a trawl through this and other forums when you are looking at a boat and know the exact make and model of engine.

 

[vyv_cox]

You may find this page useful http://coxengineering.sharepoint.com/Pages/Enginefaults.aspx

 

[paulferris1964]

Thanks all. Don't imagine I will have a sea trial, as cost of lift in \ out is likely to be disproportionate to the purchase price, so all advice gratefully received.

 

[Quandary]

I have a theory that many yachts have their engines replaced when they are less than halfway through their working life. I once took a 20 year old marine engine to a workshop for overhaul, new bearings, honing bores injectors etc. The mechanic did it because I had spent £700 on the kit but assured me that the engine did not need any of it. The workshop I used then was a 2 man outfit a long way from the sea who serviced mainly construction plant diesel engines and the odd diesel car engine, fully equipped engine repair specialists with a very high reputation, I thought I had bought the bits at a bargain price, he thought I had been ripped off.
Bits like starters, generators and exhaust boxes need replacing but if you keep the sea water out of the engine itself it is probably good for forty years.

 

[Tranona]

Thanks all. Don't imagine I will have a sea trial, as cost of lift in \ out is likely to be disproportionate to the purchase price, so all advice gratefully received.

Not difficult to run the engine with the boat out of the water to check it works. Also not unreasonable if there are doubts about the engine to withhold part of the purchase price subject to satisfactory performance of the engine when launched. Remember you have no comeback once you have paid for the boat and taken title, so you have to make an assessment (with your surveyor) in the specific case as to whether you are prepared to pay the whole amount without seeing the engine working.

 

[hartcjhart]

dont forget that an engine running on the 'hard' is not subject to the same loads as runnin g in normal water conditions

 

[greenalien]

There's likely to be a difference in engine life between one that's raw-water cooled and one that's indirectly cooled, via a heat exchanger. The latter shouldn't have any major issues with internal corrosion; with the former, it's much more of a lottery, depending on how well the maintenance was done, especially with regard to replacing internal anodes on a regular basis.

 

[onesea]

Do you intend to buy the boat without a sea trial ?

Why not if I had bought mine with sea trial the then SWMBO would never of let me buy it! Our first sail scared her sh!tless, the previous boat might of made the delivery passage in one full 6 hour tide with fair wind, we came back upwind under sail in 3 hours

It is also a great negotiating tack tick, X amount as is where lies. Particularly if your insurance does not require a survey, if not straight after survey.


When I moved up to costs I did not expect to be as much:
The cost of new clutches,
New halyards/ ropes (ok I went dyneema)
Yanmar engine spares!

We drew up a list of essential we wanted in the new boat and ticked them of the list. We knew it was going to be a compromise, I got lucky the compromise sailed much faster than SWMBO expected, she warmed to her eventually.

When you think you have decided on the next boat, draw up a list of items you think you will want to upgrade in future.

Cost them ALL up even if they are a day dream, DO NOT GUESS.
Nearly 2 years into ownership and there are only one or 2 items I have not upgraded (most boat owners I think will say the same).