My boat engine which is diesel and inboard won't start! What's wrong?

Question

We just replaced the gas tank, and cleaned all the lines out, we put it in the water and it started no problem and idled to the dock.

Sunday we start the boat and it starts fine, we're sitting there for not even 3 minutes and it just dies. Then it won't start. We sat in the hot cabin, in the hot sun for three hours trying everything! What do you think could be the problem? We tried fixing and checking all lines, connections and even blead lhe lines.

Could it be the injectors?? They are no plugs on this type of engine. There is some bypass system thing with a "bowl" for the diesel that my grandfather put in years ago, should we try just hooking a line straight from the tank to the engine?

AHHH annoyed and frustrated!!!!

Answer 1

Hi Victoria!

First, replace the fuel filter (Get used to it, you may have to do this many times before you're done.)

I 'm thinking that in the process of replacing the fuel tank and cleaning the fuel lines, AIR has gotten into the mix. I believe it'll have to be re-bled and maybe even bled mulitple times before you achieve success.

Good Luck!

Answer 2

it might have electrical problems

Answer 3

there could be air in the fuel lines . or a break in the pick up line. your fuel pump may not be working. or the injector pump may be bad.these are about the only things that will keep a diesel engine from running. unless the timing gears failed. bleed all injectors. loosen the injector line at the top of each injector and turn the en gin over until there's on more air in the fuel. each line should be done separately.be sure to use a line wrench and re tighten all lines after bleeding injectors. use an absorbent cloth to catch the spillage, this should never be allowed to be left in the engine compartment. if the engine still doesn't crank i would check and make sure the fuel filter housing is full you did prime the fuel filter. if not that has to be done. you remove the old filter and replace it with a new filter and fill the filter housing with clean fuel. make sure the housing is full and tighten it then continue the bleeding proses.

Answer 4

Since there are no electrical systems involved other that the starter, you are looking at the fuel system.  Answer #1 is good in that it covers the basics.  Diesel engines require fuel and compression.  Since it ran, assume the compression is OK.  It doesn't take much algae to clog the injectors and that where I would look.

Answer 5

if you have which im sure you do a water sepperator  it looks like a oil filter  take it off and change it could be water in it also check your fuel filter and make sure you fill it up with fuel when you put it back on the motor thats called priming it

Answer 6

The biggest problems with diesels are 1. Contamination of the fuel. 2. Air in the fuel lines.

Since you say you replaced the fuel tank and cleaned the  lines out, then it sounds as if that's o.k. We had a choice to polish the fuel or just empty it all out. We decided on the latter and discovered about an inch of sludge in the bottom of the tank.

Any air in the fuel lines will shut a diesel down real quick. You need to bleed the fuel line. You can usually do this at the secondary fuel filter, the one closest to the injectors. Be sure to put a can or something under it to catch the fuel that comes out. It's just like bleeding brakes in the car. Once all the air bubbles come out, try it again.  If it doesn't start, change fuel filters and bleed it again.  We had a similar problem on a Hunter 376. Engine kept dying or running only at low rpm. We must have changed filters a dozen times on a short voyage up the coast. We found out we had two problems eventually. One was sludge in the bottom of the fuel tank.....which I assume you don't have. And, secondly, a very small hole worn into a part of the fuel tubing where it went through the overhead in the Captain's Quarters. It was sucking just enough air that by itself wasn't enough to shut things down but eventually over time would build up to a large pocket of air in the fuel filter.  We discovered it through a series of trial and error methods, eventually hooking up a new portable fuel tank directly to the secondary filter. It ran fine then so we knew our problem was in the line from the input of the secondary fuel filter back to the tank. So we kept backing up where we would hook the new, smaller fuel tank until we pinpointed the section that had the tiny hole in it. We replaced that and bled the line. Started it up and it's been running great ever since.

There are other things that can cause this problem but by far I believe these two are the most common.

Answer 7

It starts, so the compression is good.  So all you have is the fuel system.  And on a diesel its easy, only things that can really be wrong are the injectors or injector pump.  

Just make sure you're getting fuel all the way there and where the fuel stops is where your problem is.