Sheen in exhaust water from Kohler generator

[White Shadow]

I have a 2005 320 DA with a Koehler 5E generator which would also be circa 2005 (I've had the boat for almost 2 years). I had noticed an apparent sheen in the water from the generator exhaust. I did some reading here on CSR and found a couple of discussions where the suggested fix was to change the spark plugs (and perhaps even try a hotter plug). The logic being that perhaps you're not getting a clean/efficient burn which makes sense (besides it's a cheap fix). I just changed mine and I went with the NGK BPR4ES which was the specific plug suggested in both discussions I had read. Note the plugs I pulled out were Champion RN14YC and they looked relatively OK, just a little bit of black soot on them as would be expected, nothing else look odd on them. Unfortunately this did not seem to resolve the issue - I am still noticing a sheen in the water. As a matter of fact I felt like maybe there was a more noticeable smell of gas fumes in the air around the exhaust too, although I may have been imagining that and/or the wind was still at the time.

Does anyone have any feedback on the choice of spark plugs I used? Is there a better make or model to try? Failing that, is there a suggested next course of action I could try?

 

[bahamabreisus]

I know Westerbekes were very finicky about new plugs every year or they would put out that sooty black sheen.

 

[White Shadow]

To be clear the sheen I am seeing in the water is blue/green like if there was a bit of gasoline on the surface of the water. It just doesn't look right to me.

 

[techmitch]

To be clear the sheen I am seeing in the water is blue/green like if there was a bit of gasoline on the surface of the water. It just doesn't look right to me.

That (rainbow) is fuel or oil. Are you experiencing the same sheen when the gen. is loaded or with no load? Also, how is the performance when fully loaded?

 

[Bruceflinch]

Maybe too rich in the carb setting?

 

[BillK2632]

My 290DA had a 5E - Circa 2000 - it ate up plugs like no tomorrow. However, the more I ran it - under a load - the less problems I had.

 

[BillK2632]

My 290DA had a 5E - Circa 2000 - it ate up plugs like no tomorrow. However, the more I ran it - under a load - the less problems I had.

 

[wyrman]

Mine did that last summer. When I went to change the plugs one of the wires had come off of the spark plugs, leaving it to fire on only one cylinder.
I would check to make sure both plugs are firing. They make a spark plug tester.

 

[White Shadow]

Thanks folks, you've given me some ideas. I'm hoping to get back to the boat on Friday and will do a bit more digging. I'll try to see if there is any difference cold or warm and/or under load as @techmitch pointed out. I'm wondering if perhaps it is too rich and maybe the choke needs adjusted. Maybe just the flame arrestor needs cleaning. It seems to be running fine overall, so I don't think it is only on one cylinder, plus I think one of the plugs would have been wet when I took them out, but they were both the same. Let's see what I can find on Friday!

 

[White Shadow]

I managed to spend some time troubleshooting the genny yesterday, not as much time as I had hoped because another project took longer than expected (as usual).

I pulled the new plugs I had just put earlier in the week as I wanted to verify the gap. They both had a little larger gap then the owners manual suggested (not much just a little), so I re-gapped them to 0.7mm (0.028 in.) as per the manual. I did notice that one plug was perfectly clean whereas the other one did seem to have a bit of black soot on the ground electrode (again not much, just a little). I jiggled the choke and throttle linkages and they both seemed to work quite freely with no binding or sticking. I did not have time (or the energy) to pull off the flame arrestor and/or try to clean it.

I then fired it up and paid closer attention to the exhaust output at various points (cold, warm, no-load, load) as suggested by @techmitch and this is what I observed:

Cold start: - Very noticeable sheen/rainbow. (In all fairness I had been playing with the throttle linkage so no surprise it was a bit rich at start up).

5-minute later (no-load): - Still a noticeable sheen/rainbow, although not as much as when first started.

Switched over to genny and added a load: - After a minute or two there was no longer any noticeable sheen.

After running about a half-hour with load there was still no noticeable sheen.

Took the load off and switched back to shore power: - A very noticeable sheen/rainbow, almost milky.

Put the load back on, no more sheen.

I did note that the exhaust water coming out was not warm at all, actually somewhat cold. The air temp was about 50F and the surrounding water temp would have been pretty cold (it is February after all and I am in the PNW - there was actually a thin film of ice closer to shore in our marina). Not sure if this is relevant or not.

So in summary it seems that under load this genny is fine. but without a load it does seem to be producing a sheen out the exhaust. I am open to any and all suggestions as to what may cause this - I really don't want any dirty looks when I fire up the genny when on the hook this summer!

 

[techmitch]

Yep, generators are tuned to be run under load. Run it often and loaded and you should be good to go for when you really need it.

 

[White Shadow]

So do you feel that if I run it often and loaded that the sheen currently appearing at startup or during no-load operation will go away? I still intend on cleaning out the flame arrestor and maybe spraying some carb cleaner down the carbs throat, just to see if that helps as well.

 

[Wanderer 290]

A sheen on the water is not normal in any circumstances. I suspect it is running rich.
Since the spark plug replacement did not eliminate the sheen entirely check the choke operation. It is controlled by a bimetal spring heated electrically. They go bad after time and unfortunately the spring has been discontinued. I corrected mine by adjusting it full lean because the generator is never run in cold weather conditions.
Next on the list is the carb. It is susceptible to corrosion from moisture and is also susceptible to ethanol fuel. I tried rebuilding without success so I replaced it. A significant savings can be realized by sourcing the carb directly from Kawasaki.

 

[techmitch]

I think that a little at start up is probably normal, especially in colder climates. Run it loaded.

 

[Wanderer 290]

I think that a little at start up is probably normal, especially in colder climates. Run it loaded.

I think that a little at start up is probably normal, especially in colder climates. Run it loaded.

definitely not “normal “ but I guess if has to be done do be it.

 

[White Shadow]

I'm still working away at this. Last time at the boat I pulled off the flame arrestor and visually checked the carb, all looked good. I took apart the choke and lubricated it all, when I reassembled/re-attached it I rotated it so that it was basically forced fully open (just to be sure). I fired it up and am still seeing a noticeable sheen (milky) on the water and noticing a fuel smell. I put a load on it and the sheen remained - I didn't have a lot of time to leave it running so I shut it down and left it for now. At this point I am starting to think it worse than it was before I changed the plugs. I'm going to clean up the Champion's I had removed and re-gap them and see what happens when I put them back in. If this continues then I'll be looking at the coils and/or possibly a new carb from Kawasaki.

 

[Michael Mirra]

I had the same problem with my westerbeke. Tried everything mentenioned above with no luck. Eventully took the carb off and had my marina send it out to be rebuilt. Runs perfect now. Much quiter with no sheen or soot.

 

[White Shadow]

The latest in my Genny Saga:-

I decided to try swapping in the old spark plugs (after cleaning and re-gapping of course) just to see if it made any difference. It turns out it didn't and the sheen in the exhaust remains, loaded or unloaded - it's still there. I'm pretty confident it is gas and not oil. I say this as you can definitely smell gas and the sheen dissipates pretty quickly.

However, I did come across some interesting things while doing this swap. When I pulled out the new plugs I had installed 2 weeks ago they looked completely different from one another. One still looked like it was brand new, the center electrode was still shiny and the ceramic insulator around it was still white. Whereas the other plug was tarnished and turning black and even seemed to smell of fuel (picture below if I've figured this out properly). I'm hoping this might be meaningful to somebody (like @Stray Current or @techmitch for example). I've also included a picture of the old plugs after at least 2 years (that's how long I've owned the boat). Aside from the corrosion on the metal shell they look more-or-less the same. Although the one center electrode insulator looks grey and the other black, and one does seem to have more black going up the threads.

I also took this opportunity to check for spark. I put a screwdriver in the spark plug wire and held it just off the block while I cranked it over, and both coils seem to be producing a spark. In addition the motor actually started with one plug disconnected. This worked on either cylinder, the genny would start and run with just one plug connected. So now I also know that both are working.

I believe now my next course of action is to replace the carburetor, however I'd really like to know what could possibly be happening with the carburetor that causes the spark plugs to look so different? Or maybe this is just a red herring, I don't know. I've been researching the carb and have had some troubles confirming exactly which carb is the correct one. I'd really like to go with a Kawasaki one as they are about half the price of the Kohler one. The model number of my engine is the Kawasaki FD501D-ES04 and I have not had much luck finding any parts lookup that includes that "ES04" suffix. The Kohler part number only seems to come up as "359847" and they are in the $400 (USD) range. When I look for the Kawasaki FD501D the part number that comes up most often seems to be 15004-0773 but I have come across some evidence that suggests for the ES04 suffix the actual part number is 15004-2741 - these Kawasaki carbs are typically in the $200 (USD) range. Is anyone able to confirm exactly which part number I need?


New plugs after 2 weeks and maybe 1 hour run time:

Old plugs after 2+ years:

 

[Wanderer 290]

Research this site for your carb. They have listings with the various suffixes and note that most still use the same carb.

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/kawasaki/4-stroke-engine/fd501d/fd501d-fs00-4-stroke-engine-fd501d/carburetor

 

[Stray Current]

I will go back and read the whole thread later, but the post I was tagged in shows Sheen on the water and a clean plug. that tells me you’ve got no fire on one cylinder and your fuel air charge is going right out the exhaust.

Admittedly I have never touched the carbureted version of the 5K W but I would say it’s probably not carburetion if that is just a simple plenum. As with most things I would recommend starting with a compression test and a spark test. It could be as simple as a bad spark plug or coil. Could be valves out of adjustment resulting in no compression and no fire but I wouldn’t think it would be that clean if that was the case.

My money is on no spark on one cylinder. Definitely not good to keep running it that way as the raw fuel will strip the lubricity of the oil off the rings