3116TA Smoke on Startup

W

Warren

Guest
During our recent vacation the port engine started to expel some black smoke at startup and there was some black oil-like film near the port side exhaust.

I wasn't particularly concerned as the smoke would only occur at start-up and it and the black film disappeared within a couple of minutes as the engine warmed. There is no noticible change to the oil level and the engine seems to idle normally and it runs fine. It might be just a tiny bit hotter than the stb. engine after a couple of hours running, but is hardly detectable (if the temp guages can be totally relied upon for such minor variances - ie. 1/16" difference).

Is there anything that I should be checking (ie. port Racor)? Most diesels do smoke a bit and I wouldn't be concerned unless I noticed this as an operational change. Any suggestions?
Thanks,
Warren
 
One thing to check/do would be to clean your airseps. After that, I can tell you that I already agree with Frank W and he hasn't even posted yet.
 
Black smoke typically means a rich fuel charge (improper blend of fuel and air with more fuel than desired) on a diesel. Dominic is right, the first thing I would check is the Air-Sep to be sure it is clean since an engine starved for air will have less air in the cylinder that it is supposed to and will result in black smoke.

However, I'm not sure you have a problem if the smoke clears quickly because starting a diesel creates a rich condition until the cranking speed is fast enough to fire the cylinders. A few seconds of black smoke is very normal. And, don't forget that there are some plumbing differenced between the port and stbd engine exhaust systems. Something as simple as more tubing or more water in the muffler can affect how much smoke you see in the air. Black smoke is unburned or incompletely burned fuel and it settles in the water as carbon...black dust or soot. If the 2 engines smoke differently, look at the surface of the water and see if the side with less smoke has more carbon floating in the water.

Believe it or not, one thing I would check is the battery condition. If you do not have adequate cranking amps from your battery bank, the cranking speed will be slow and ignition will be later than it should be.

A final cause of black smoke may be one or more injectors that are not atomizing the fuel charge properly. This isn't likely if the engines are smoke free and perform normally after you get them up an running.

Maybe that gives you a place to start.........
 
Ditto Dom and Frank. This spring brought a small puff of black smoke and carbon in the water. Quick clean of the K & N's off the Airseps did the trick.
 
Not to hijack, but....

How much smoke is considered "normal".

I have noticed lately that on starting, I also have some smoke from both engines at startup, along with a small amount of "soot" on the water. Seems like nothing major and according to what I read, this is probably normal.

What I also have noticed is that the swim platform and transom always has a light coating of the black stuff after a run. It usually wipes off and I clean and rewax every couple of weeks to make it look new again.

Is this normal for us oil burners, or should I be concerned???
 
Soot on the transom is not normal for Caterpillars. It probably means you are slightly overloading the engines due to a little too much prop, a dirty bottom, or enough weight on the boat that you ae not able to turn up 2800 rpm at WOT.

Another cause for soot/smoke on start up is valvas that need adjusting. This is a required service at specific intervals, the first of which is at 250 hours. If you haven't had it done or don't know, get it scheduled soon. As the valves on a Cat engine wear in, they get tighter which means they open sooner and stay open longer, and it puts you at risk for a valve hitting a piston. That isn't pretty on these engines and if it happens, a stolen identity would be cheaper to deal with.
 
Thanks Frank W. Green Balls to you!!!

CAT is coming out on Friday. I have requested they adjust the valves as I am now at 330 hours and don't believe the previous owner did this. I have also asked them to give the engines the once over due to the soot thing.

Any other specific questions I should ask or items that should be checked out specifically would be appreciated.
 
Honestly, just resetting the overheads is all you need a Cat technician for on these engines.

Everything else is just handling the replacables like sea water pumps, cleaning heat exchangers, changing filter, changing antifreeze, etc. unless you break something or if either engine starts losing cylinders (missing) at high rpms. If you do lose cylinders, the fix is easy, but does require training and special tools. This sometimes never happens, but if it is going to, you have until about 800-1000 hours, total, before it will. Run me down at the time and I'll talk you thru it.

In the meantime, just enjoy running trouble free engines.
 
Good suggestions. The Airseps seem relatively clean - the indicators have not "popped" and I had a Cat mechanic on the boat at the end of July and he said that they looked OK and didn't require cleaning yet. Still.. good suggestion and I will consider buying a cleaning kit (another new experience!) if the start-up smoke persists. What are K&N's??

Frank, the batteries are all new, installed new batteries (6 x 6v. and 1 x 12v.), inverter/charger, amp/hr meter, etc. in July so there should be lots of juice on tap for ignition!
Warren
 
No Gary............

There are no head, aftercooler or valve issues on these engines. Occasionally an injector seat will leak requiring it to be reamed and reseated. With Caterpillar's unit injection system if an injector seat leaks, combustion gas or air gets into the fuel chamber and all the injectors after the bad seat get airbound and it kills the cylinder. Its a simple easy fix, but dos take a special reamer and experience.
 
Warren.

If you haven't yet, then clean the filters. It's an anual maintenance chore. I don't think you can really tell the filters are dirty by just looking at them. And those 'poppers'....if they do 'pop', your filters are filthy.

K&N is the brand name of the company that makes the filter elements for Airsep. You can buy the K&N filter cleaning kit at Autozone, PepBoys, etc for about $12.

There's a good discussion on cleaning the airseps here....

http://clubsearay.com/forum/showthread.php?t=4929&highlight=airsep
 
As was said, black soot is often due to overloading, which can come from nothing more than a dirty bottom; and it doesn't take much- no hard growth, just a month's worth of slime from non-use. At least that's the case with my 3208's...the diesels seem to be easily susceptible to overloading, especially if you're propped at the "edge".

Have you verified WOT rpms (under load) recently while out?
 
A dirty bottom causes black smoke when you start the engines?

I think he needs a new aftercooler.
 
Good suggestions here. WOT is normal at almost 30kn and and as I said earlier, performance is fine once they are warm. Thanks for the details Dom, I'll try to source the kit locally in Canada as we don't have the distributors that you mention. Perhaps NAPA will stock it and yes I'll re-read that thread, good suggestion and thanks for the link!

The Airseps look somewhat dirty but not filthy - I can's see any difference in a season's use since I bought the boat but I'm sure it can't do any harm to keep them clean as an annual PM measure. As I recall Cat sell the kit and that in-line filter (do you just replace it?) but it will probably be 2x the cost if I can source direct.
 
Warren:

NAPA has the kit also. If by inline filter you mean the vacuum regulator........


vacuumregulator.jpg


........ then no, you do not replace it. You clean it the same way as the larger main filter.
 
Yes I mean vacuum regulator, thanks Dom. I'm going to find time for this job next week.. and I'll make it a part of spring commissionning starting 2010 (gosh, am I that old!). Oh, and it was a bit unclear from the comments - do I need 2 kits to clean the 2 vacuum regulators and 2 airseps??
Cheers,
Warren
 
Does anyone know how many times can you clean the (K&N) Air Sep filters with the kit? I thought I read somewhere that it was three times before you should buy new filters.
 
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