Injectors or Pump

[hooligan6a]

I think I have a problem with my injectors or my pump. I have white smoke coming out of my exhaust but only while underway. If I put it in neutral and rev it up, it does not smoke, even when tie to the dock and rev it up to 2500 rpm there is no smoke. only underway. Is there any way to tell if this is caused by the pump or the injectors? Oh yes, there is a small loss of power.

[SVHALLEL]

What is the engine make and year. To check a mechanical pump usually you can run the engine at idle and crack open the fuel lines at the nozzle. This will create a missfire in that cylinder. If there is no change then you have found the cylinder that has the problem. No fuel and it may be the injector pump. Have alot of rags handy or spill cloth.

[hooligan6a]

The engine is a Yanmar 3GM30f It is not the fuel pump the engine is running fine, it just smokes. Starts right up, and no over heating.

[SVHALLEL]

If it runs fine at idle white smoke with a heavy diesel fuel smell and / or fuel traces in your exhaust water would sometimes mean unburned fuel. It only needs compression / air / fuel. Next would be to have compression checked. If you have a temperature gun you can check the side of the engine when it is cold and just started. Check each cylinder and one will be cooler then the others. When you rev it you are speeding the piston so if there is a leak in the cylinder ( valves or piston rings) it will cover it up.

[SVHALLEL]

Seen a couple of other things before also. If the engine has alot of hours they will smoke when cold and go away when warm. If it has a bad thermostat it may be staying too cold and creating that issue. Had another that was not allowing enough cooling water in the exhaust and the smoke was steam.

[hooligan6a]

This is smoke not steam, There is no overheating. If you rev it in neutral or tied to the dock it does not smoke only underway, the boat must be moving. IMHO, It can only the be Injection pump or injectors. It starts fine and runs fine it just smokes, pretty bad.

[never monday]

Originally Posted by hooligan6a

This is smoke not steam, There is no overheating. If you rev it in neutral or tied to the dock it does not smoke only underway, the boat must be moving. IMHO, It can only the be Injection pump or injectors. It starts fine and runs fine it just smokes, pretty bad.

what happens when you run it in gear, tied to the dock?

In my opinion it can be more than injectors or the pump.

[hooligan6a]

It only smokes when underway, no smoke when tied to the dock and revved in gear, No smoke when in neutral and revved.

Why do you say it could be more than the Injectors or pump? The engine starts easy and runs fine. It just smokes.

[never monday]

Originally Posted by hooligan6a

It only smokes when underway, no smoke when tied to the dock and revved. No smoke when in neutral and revved

so if you are tied to the dock and in forward gear with the engine at 2500 rpm. is there smoke?

[hooligan6a]

No, it only smokes when underway. No smoke it any other time, only underway.

[never monday]

first inspect the impeller.

[hooligan6a]

Ok, I will do that, I also checked the propeller and had it cleaned by a diver.

[never monday]

oh, then check the exhaust mixing elbow

[atoll]

is there water in the fuel? white smoke can also mean water mixed in with the diesel.

bleed the fuel bowl on the filter,if full nearly to the top it will look like fuel,but as soon as the boat rocks slight ly you will be getting a diesel water mix

[Badsanta]

Originally Posted by hooligan6a

The engine is a Yanmar 3GM30f It is not the fuel pump the engine is running fine, it just smokes. Starts right up, and no over heating.

Try the Island packet factory site iphomeport.com or the islandpacket owners group.

Have you tried being tied to the dock in gear at 2500 rpm after you have just come back and have a nice hot engine to see if it smokes? or do you try this at dock before making way. If it only does this with a hot engine and not cold. I would agree with the others to check your exaust elbow. It is concidered a wear item and needs replacement every few years.