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patrickbwells 03-30-2007 03:15 PM

Diesel engine help
I recently bought a 36' project sailboat at auction and the engine has not been started in about a year. It is a pretty new Isuzu Marine Diesel with very little rust or corrosion. What should I do to the engine before I start it? Does anyone know of a good guide on this subject? I don't anything about diesel engines but am mechanically inclined, have tools, and lots of time (but not much cash). Thanks.

ianhlnd 03-30-2007 03:30 PM

besides making sure all the hoses are in good order, check the water impeller on the cooling pump. After not running for a year, it may be stuck and will tear apart when it rotates. If hoses and impeller are OK, you may try tapping the start button to see if it turns over. If it just clicks, stop, the pistons may be frozen and you'll burn out the starter.

A boat as you described it probably has glow plugs. Maybe not if it's a new Isuzu, If it has gp's gunkus can grow from the end of the electrode which will cause it not to glow. Check those.

Some will pull the injectors and spray a light oil or WD40 directly into the cylindars before starting after a long lay over. Good idea, gets lubrication to the pistons immediately and may help break up any corrosion on the walls.

Prime the fuel pump, making sure you have good clean fuel. Sitting for a year....more gunkus. May have to bleed the system.

Oh yeah, if it starts, check the exhaust to see if it's pumping water, or smokes...white means water in the system, black is too rich.

That's about all I can think of right now, good luck

Ronbye 03-30-2007 03:42 PM

First of all, if the engine has a handcrank, then turn the engine over by hand to ensure that the pistonsand everything else is freely moving. Check the fuel filters and make sure there is no major blockage in this area. Check your oil levels. Make sure you have lots of fuel in the fuel tank. Batteries are fully charged and that the electrics are for starting the engine and properly connected and secured. If the boat is out of the water ensure that you plenty of water for the engine(the water inlet hose is in a bucket of water and that there is lots of water to replace what is being drawn into the engine) If the engine is fresh water cooled( closed cooling system make sure that there is plenty of coolant in the system.

If everything checks out and is ready, you should be able to start the engine. But before you do, just turn it over for a few seconds without any throttle on. This will loosen the engine up a little better than just using a hand crank earlier. If it has a glow plug, then turn this on, wait the a few seconds, and start the engine as per the manufacturers recommendations.

It probably won't start right away. If it doesn't wait a minute or so and try again. When it starts, it may stumble a bit, but should settle down once it starts to warm up. Check the exhaust for water. There should be water coming out of the exhaust. It shouldn't be a dribble. It may pulse a bit but that is fine. Once the engine is running ok, check that she is charging your batteries. You may want to let the engine run for a period of time to get to close to operating temperature. After which, when the engine cools down a bit, you can change the oil and oil filter. That is the essentially it.

Nigel Calders book Mechanical & Electrical Handbook for boats is an excellent resource.

eherlihy 03-30-2007 04:03 PM

I would reccomend the following in sequence:
  1. Remove the injectors - while they are out, you may want to have them serviced by a pro, or not...
  2. Crank it over (to see what comes out of the fuel tube, and the cylinder head:eek: )
  3. Change the oils (Engine & Tranny)
  4. Clean the fuel tanks (hopefully you can)
  5. Replace the air & Fuel Filters and clean the water strainer
  6. Replace the belts (note that I would NOT change the impeller, but I'd definately have a spare available)
  7. Reinstall injectors
  8. Bleed the fuel lines
  9. Fire it up
  10. Check the water flow from the exhaust
  11. enjoy :cool:

Remember - Free advice is worth every cent:p

EscapadeCaliber40LRC 03-30-2007 04:09 PM

I would guess (never been there myself) that you should start with an oil change, check all hose lines leading to engine and tank for bad or missing connections, change out the filters if you have any, and drain the Racal water traps if these are in place, bleed all introduced air out of gas lines afterwards, check the starting battery for power and wiring to starter for good electrical continuity, check condition of belts, check condition of impeller and replace if questionable, check condition of throughhull and intake of cooling seawater including filter making sure it is clean and flowing to impeller, examine exhaust path as best you can for rust and corrosion, manually crank it over, check fuel in tanks and in filters for proper color, try to sample fuel from bottom of tanks, then turn the key and see what happens. Somewhere in the midst of this checking activity, I would recommend that you also locate a near by source of good diesel mechanic skills and engage they in some practical "what if" questioning. If all these check out chances are you will have compression, and power to the starter motor. So if the starter turns it over, and the fuel is present,with air properly bled out of fuel lines, it should fire up. Contaminated fuel is probably your main risk. If it starts to run, immediately check for sea water flow out the exhaust pipe (should be there) and examine exhaust smoke if present for color, and check for smoothness of engine running, watch oil pressure gauge for proper reading, shut down promply if anything seems suspicious. You know how to cut the fuel source right ?

Guesser 03-30-2007 04:16 PM

Make sure the fuel in tank is still good. If there is room, top it off with fresh fuel.

btrayfors 03-30-2007 04:40 PM


All good advice above.

My recommendation is a bit different, though.

Take your last penny to the bookstore and buy Nigel Calder's Marine Diesel Engines.

At Amazon, it's $18.45 new in hardcover or $13.14 used. Marine Diesel Engines: Books: Nigel Calder

It's the best investment you can make to keep your Isuzu diesel humming.


Freesail99 03-30-2007 04:47 PM

I just bought the one for $13.14, thanks for the tip :)

Alden68 03-30-2007 05:07 PM

From experience....make sure that the controls that stop the motor are functioning. Trace the control wire/cables from the stop mechanism back to the motor and make sure you know how to operate them by hand. There is nothing worse than gettig a laid up motor running again only to realize you can't stop it!

Check and change all of the fluids and definitely change the impeller. If it is frozen and breaks apart on start up, pieces of it can get lodged in your raw water pipes. Also it is good practice to know where and how to access the impeller and how to remove/replace it.

Assuming your boat is on the hard at the moment, make sure you supply water to the intake while she runs and minimize the time you run the motor in gear as you can burn up your cutlass bearing.

Good luck and enjoy the project!!

p.s. - Nigel Calder's book is great. Don't get overwhelmed when you first look at it. The more you poke around your motor the more sense it makes!!

EscapadeCaliber40LRC 03-30-2007 05:08 PM

Agreed, buy all the Nigel Calder books. You can't afford not to.

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