Diesel Engine won't start

NCShadowdragn · #1 (**permalink**) 02-09-2009

Have a 1985 Hunter sailboat with a 3 cyl. Yanmar diesel engine that was rebuilt just over a year ago. No glow plugs. Ever since rebuilding, the engine has been hard to start especially in the cold weather. Been having to flip two of the three compression switches to help start but now that isn't even working. Some white smoke coming from exhaust while trying to start. Any suggestions or possibilities of what the problem is?

djodenda · #2 (**permalink**) 02-09-2009

Welcome to Sailnet!

We can be a bit more helpful if you answer a couple of questions:

1) What kind and model of engine is it?
2) Does it have a glow plugs?
3) Does the engine crank as fast as it did when it used to start?
4) Have you done anything to the engine recently?

David

peikenberry · #3 (**permalink**) 02-09-2009

If a diesel won't start it generally is due to one or all of three things
fuel not getting to the cylinders
air not getting to the cylinders
not enough compression

smoke usually means unburned fuel, but not white smoke. White smoke usually means water in the cylinders. This could be a head gasket leak.

First check cranking speed. Is the battery charged and strong enough to crank the engine fast enough. Otherwise you are not getting enough compression for it to fire.

If cranking speed is up and compression ok check your air and fuel filters to make sure they aren't clogged.

Check to see if you have water in the fuel. Water makes diesel fuel look milky.

If you have glow plugs make sure they are working. Cold weather always causes hard starts but glow plugs help.

If you still have the problem then you need to have a diesel tech run some tests.

jrd22 · #4 (**permalink**) 02-09-2009

I'm guessing you have a Yanmar 3gm, but they are all similar. White smoke while cranking can be unburnt fuel, ours did that and we had the injectors rebuilt (and then replaced). That helped the hard starting and reduced the white smoke. Another thing that we have used recently that seems to help is something I read here on Sailnet. Pull your stop cable out and crank for 10 seconds and then push the cable in while cranking, usually fires right up. Hope that helps.

timebandit · #5 (**permalink**) 02-12-2009

???NO FUEL IN THE TANK???

Trouble shooting requires questions and answers.

Quote:

Originally Posted by NCShadowdragn

Have a 1985 Hunter sailboat with a 3 cyl. Yanmar diesel engine that was rebuilt just over a year ago. No glow plugs. Ever since rebuilding, the engine has been hard to start especially in the cold weather. Been having to flip two of the three compression switches to help start but now that isn't even working. Some white smoke coming from exhaust while trying to start. Any suggestions or possibilities of what the problem is?

SteveInMD · #6 (**permalink**) 02-12-2009

No fuel in the tank is a good guess. An air leak in fuel system is another.

badsanta · #7 (**permalink**) 02-13-2009

I have to do this on mine when cold. Make sure battery is full. I turn off the water intake. Open all the decompression levers, crank for 5-10 sec to get the oil moving. open to 3/4 full throttle, crank for 5 sec. close decompression levers and start, reduce throttle to idle and open water valve. I think that the increased oil pressure and the fuel increases pressure. The white smoke is probably just unburnt fuel. But you don't want to just keep cranking the water through the engine

Joesaila · #8 (**permalink**) 02-13-2009

Where you just had it rebuilt I would suspect the battery is too low. If you live in a cold climate the sugestion re closing the seawater cooler is right on. That suggestion re opening the decompression levers is worth trying too. Let us know what works.

hertfordnc · #9 (**permalink**) 02-13-2009

Someone mentioned the battery- Specifically, the battery and wiring

look closely at the wiring from the battery to the power side of the starter (that's the big terminal) Also check where the negative cable connects to the engine (ground).

Check every connection. Look for corrosion on the terminals. Peel back the insulation and check for corrosion (green)

Your electrical system can work fine in all other respects but if there is corrosion on those big wires it creates resistance which turns current to heat.

That will cause your starter to turn slower and fail to start the engine.

Electrical problems cause confusion. A good battery and wires will allow the engine to spin fast enough to start and that may overcome worn valves or injectors. Likewise, fixing bad valves or injectors may allow the engine to start easier despite a week electrical system.

But wires are cheap and no skill is required and it's pretty hard to make it worse so it's the best place to start.

NCShadowdragn · #10 (**permalink**) 02-13-2009

Plenty of fuel in the tank. Thanks for all the suggestions. We plan to head for a dock under sail tomorrow and get fully re-charged and try again. Will let you know how it goes. Again, thanks for all the suggestions.