what to look for when buying a used diesel motor??

[Cruxandreams]

Hello all, I am looking at buying a diesel motor of some kind for my 33' boat of around 25-30hp and know very little about motors and would like to know if anyone has any input or pointers on what kinds of things to look for before purchasing a motor. obviously hours, but what if they are unknown? will any motor work if it is roughly the same horse power and size? what kind of cost would I be looking at if I wanted to get it professionaly rebuilt? Is there a limit to the life of a diesel or can they keep going and going if you take care of them? any and all ideas and comments welcome. Thanks Zach.
p.s.
I have had a couple motor in my sights in the past few months, but am afraid to spend thousands on something I know so little about.. any services out there where some one could look at the motor for me and tell me if its a good or bad deal/motor?

[emoney]

I'd definitely suggest finding a local diesel mechanic that comes highly recommended to help you in this process at the very least. The drawback to purchasing used motors is you normally have no idea what it's true history really is. Sure, a well maintained motor of any type, especially diesel, can serve an individual for their lifetime if cared for. However, that same motor can be mishandled by one owner in its life and fail you on your first outing. Try to find a motor, if you buying used, that the seller is willing to warrant for a normal amount of time (6 months, imho, is plenty). Better still, and it would be my advice if it's an option, find either a professional built motor or a new "drop-in" replacement. These will always come with a warranty and they can either install it or recommend someone trustworthy that can. The PO of my boat had just repowered with a 20hp Universal that was rebuilt. It came with a 6mo warranty and cost him in the neighborhood of 4500 installed if that helps.

[arf145]

Do you know what kind of engine your boat had before? The easiest thing would be to replace with the same one--the engine bed will have been made for that. You might need to mod the boat to mount some engines. So, most likely, this is not just a drop it in situation.

[hellosailor]

Crux, call Dick Vosbury at Vosbury Marine in Annapolis. A family business and incredibly reputable. I'd take his word on whether your engine needs rebuilding, and whether it is worth doing, without even asking a second opinion--and I don't do that often.

Replacing an engine often means problems with fit, new engine mount beds, installation costs, unless there's a drop-in replacement for it. But give him a call, you're lucky to have some real pros local to you.

[davidpm]

Originally Posted by Cruxandreams

I have had a couple motor in my sights in the past few months, but am afraid to spend thousands on something I know so little about.. any services out there where some one could look at the motor for me and tell me if its a good or bad deal/motor?

I agree it does seem to be a leap of faith.
What is the story on the motors you have looked at.
Age, history, cost how did you find them.
Does the cost include installation and if not have you found someone to do that too?

[INMA]

Compression test, inspect the oil and water coolers, inspect the water pump, spectrographic test of the oil for wear.

All easily done by any competent diesel mechanic.

If you don't have the skills or knowledge, pay the bill to get it done.

Then have things like crankshaft seals replaced to make sure the engine will be trouble free for a few years.

[davidpm]

[QUOTE=emoney;780604 The PO of my boat had just repowered with a 20hp Universal that was rebuilt. It came with a 6mo warranty and cost him in the neighborhood of 4500 installed if that helps.[/QUOTE]

That is very interesting. What kind of place did he buy from?
IOW did the place that sold the motor install and warrentee it?

[Frogwatch]

In 2002, I bought a Yanmar 2GM13 online sight unseen for $1750 because I thought it would be a direct replacement for my 1GM. I managed to get it started so decided to install it myself. Boat was in my back yard on jack stands with no way to hoist motor up or get a crane near the boat.
Old motor came out easily. I used the winches to lower it to the ground. New (used ) motor was on a plywood skid. Put ladder against the boat and used winch to hoist i up to the cockpit and then rolled it over to some 2X4s going into the cabin and down a ramp into cabin. Walked it aft and then levered it into place. DANG, it didn't fit, too high, had to cut 3/4" off the engine stringers with a carbide coated jigsaw, used up 6 blades on those thick glass/mahogany stringers.
Then, the engine mounts were bad, so I ordered some and made them fit. Aligning the shaft was fairly easily done with feeler guages.
It runs very well, if it hadn't, I was prepared to rebuild it.
THEN got into finding a good prop. Finally settled on he PerfectPitch prop, a massive plastic casting that I love.

[LakeSuperiorGeezer]

For a 33 foot boat, maybe 20 hp would be better as it would be easier to fit into the boat and this hp would drive the boat near hull speed. Also it would be cheaper to purchase and use less fuel. With all the boats being junked out because folks are walking away from them, engines should be available cheap. Look for engines that come with heat exchanger. Do not ever consider anything that had direct seawater cooling. Probably any engine you buy will be out of the boat and it would be harder to assess its condition. What engines are usually specified for your boat? The navel archatect would know engine size and propeller required. Beam at water line and water line length can be plugged into equations to give a better idea of engine size.

[night0wl]

My recommendation would be to take an introduction to diesel maintenance course at a community college before buying a diesel engine. They're remarkably simple machines, however can bedevil you with their elegance at times.

But if I were to buy a used or new diesel replacement, here is what I would look for:

1) Drop in replacement so that I'm not fabricating mounts. Doing the mounting is labor intensive, and assuming your level of knowledge about diesels, its likely to be done by a yard at yard rates. This can really run up the bill very fast.

2) Availability of cheap parts globally. There is a reason why Yanmar and Beta are the most popular engines out there. You can be nearly in any port and find drop-in parts for those diesels...or get them easily

3) Look for historical design flaws. Find out what common issues there are with that particular model of engine over its run life. Internet has made this very easy to do. See if those design flaws have been corrected

4) On a used engine, I'd look for about 50-100 hours per year of age with documentation of all service(s) performed on the engine. Probably would not know look at a used engine with more than 1000 hours or 10 years of age on it, unless it was winterized/mothballed very well.

5) If you're replacing the engine, you will be replacing all the running gear as well. This means shaft, likely a new prop, new controls at the helm, wiring/electrical from the battery...etc. LOTS of work, lots of labor getting these all done. Better have a really good punch list.

6) Used engine should get surveyed by a good, trusted mechanic. Compression check, injectors, look for extraneous fluid leaks/stains, etc.