My trusty 2GM20F has been running flawlessly for many years. Sooner or later I was bound to run into something I was going to have to deal with.
For the last 50 or so hours of operation I have noted an excessive amount of WHITE smoke along with a very obvious fueley smell.
Given the boat completed a sail to Hawaii and back last year, a trip which included a lot of at sea refueling from 5 gal jugs, I figured first step would be to completely clean tank, filters and lines up to the hi pressure fuel pump. Accomplished this and also upgraded the primary filter to a compact Racor fuel water separating filter assembly with a bowl. Previous filter was just a filter, no observation bowl. Also purchased a diesel dry additive to enhance water protection and to clean injectors to the extent an additive can actually clean them. I did find some debris in the tank and some slight gelling plus quite a bit of dirt and a little water. It was not a shocking amount of contaminate. I have now run about 20 gals of known clean and treated diesel through the system and white smoke is still an issue.
Oil burn seems minimal minimal - about 8 ounces per 40 hrs running (engine hours at about 1800 - best estimate including WAG on POs usage)
No coolant is being consumed
Engine power is nominal at all RPM
engine runs well, no weird noises
Air cleaner has been replaced and is clean
I did note hard starting in colder weather (40s 50s) but this symptom seems to have cleared with warmer weather (60s) and possibly clean/treated fuel benefit. Engine historically started up quickly in all weather here in California.
The plan going forward is:
perform compression test - tools on the way - if this fails I need to reboot my strategy, I am banking on compression being OK due to overall engine performance being OK
Remove and replace both injectors - injectors on the way (never been replaced during my ownership - 1200 hours)
perform valve clearance inspection and adjustment - never been done (yea, I know)
White smoke is caused by raw, un-burnt fuel passing into the exhaust stream. Common causes include:
· Incorrect fuel injection timing
· Defective fuel injectors
· Low cylinder compression
Low cylinder compression may be caused by leaking valves, sticking piston rings, ring wear, cylinder wear, or cylinder glaze. When white smoke occurs at cold start and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing.
Continuous evidence of white smoke indicates a mechanical defect, or incorrect fuel timing.
The causes Geoff mentions give a white/ light grey smoke which also stinks.
Another cause and giving white smoke which doesn’t stink: too little water injection in the exhaust system
resulting in a too high exhaust temperature giving water vapour.
It looks like my plan is consistent with the possible faults.
I believe I am good on water flow through the mixing elbow/exhaust. I replaced the elbow several years ago due to zero water flow so been there done that. Today I have excellent flow through the system as evidenced by good water flow at the exhaust, no overheating indications including smells of burning rubber and the like.
I am really hoping it is the injectors which seem the most likely suspect. Compression issues sound like money unless it is something simple like poorly adjusted valve clearances. Fuel injection timing might also be fixable on a DYI basis but the procedures to time the fuel injection look tricky.
As a general note, it is too bad there is not a comprehensive fault tree on these engines. I have to believe that there are other indicators of, say injector issues vs compression issues but nothing I have seen takes you to the next level. You read white smoke could be caused by these six things. Fuel smelling white smoke with no oil burn and no coolant burn reduces the possibilities but then the fault tree seems to come full stop. Seems like there could be some further indications which would lead you to suspect injectors vs compression but I’ve not been able to find these discussed anywhere.
replaced the injectors with rebuilt units and she fires up and runs just like she used to. No white smoke, all is good.
Bottom line was an injector issue. I bought three rebuilt injectors, replaced both in the engine so I have one left. I will hove one of the two originals rebuilt in order to have a complete set of spares on the boat. Learned a lot doing this project myself, very worthwhile.
I never did a compression test. I was saving that for last ditch effort if injectors did not work.
I bought a torque wrench for this project (about $35 on Amazon) this was really useful. When I pulled the injectors I felt like the hold down flanges were not very tight. Now I am sure they are torqued to factory spec.
I have a 1988 Freedom 28 with a Yanmar 2GM20F…every time I use the boat under power the transom develops a black mustache…easy to remove with soap and water, but why does it happen?
I’m sure others will comment but in my experience, some diesel soot on the transom is inevitable, even for a properly running engine. How much soot is a subjective call but in my case it’s sort of like a dirty windshield look. Not dense black but a variegated dirtiness which is most visible within 18 inches either side of the exhaust out and extending up the transom about a foot. Short motor (1 hr) No issue, long motoring ( 12 hrs) definite visible build up (think dirty windshield only black not brown). If it’s a lot worse, you may have something going on. Are you seeing any visible engine smoke? If so, what color?
I have seen a few boats which have a small flexible hose attached to the exhaust outlet. This places the actual exhaust output about 18 inches behind the boat when motoring. I assume the intention is to keep the soot off the transom and gases out of one’s lungs. Such an extension would probably not be desirable on our boats where the exhaust outlet is very near the waterline.
Word to the wise, if you fix something and then you start having the same problem in a few months, do not perform the same fix without going through all the troubleshooting steps.
Case in point. My white smoke started again after 45 hrs of engine ops. Rather than do full troubleshooting I told myself, must have installed flaky injectors. So i pulled the injectors and slapped my spares in there. Problem solved - for about 8 hours - then back to white smoke. This was on a trip up to an SF Bay race. The trip up was bumpy and cold. Got to Berkeley Marina with no issue but she was smoking a lot when I arrived. Shut the engine down and could not restart…period… AARGH… I had one day to fix.
I had been looking at the primary Racor bowl during this episode and could see no water under the diesel so my initial though was - well it’s not water. but just to be safe I drained the bowl. Guess what, all the visible liquid in the bowl was water!! Holy crap says I - or something along those lines. Anyway, off the filters came and sure enough, evidence of crud and water in both. So this meant the tank had to be opened again, Did that and found about a cup of water lurking around the pickup area. During the bumpy ride I am sure a lot of water got sucked into the fuel system.
So out came all the fuel via the inspection port and my handy 10 ounce plastic measuring cup. Then a thorough cleaning of the tank interior, then replacement of primary and secondary fuel filters, then replacement of both injectors - for the third time is six months. (Note: if anyone on the West Coast needs 2GM20F injectors replaced, I have become and expert and can do it in two hours flat). Literally a whole 10 hour day getting this stuff done at the transient dock in Berkeley. Engine started right up and ran like a top. Made it over to the race and back home. Now I need to troubleshoot how more than a cup of water made it into the tank over a period of six months. There must be a leak at the fill cap because I am almost sure I have not been putting wet fuel into the tank.
I also need to take two more injectors to Diamond Diesel for rebuild. Those guys see me and say “here comes our best customer” I am singlehandedly keeping their business afloat.
Mike - how full of diesel was / has been your tank? In our cold weather, if the tank is not always full, condensation can occur and water forms inside -I don’t know about how much forms… but worth a thought. Your descriptions are way more than my knowledge on yanmars…
Funny (and yet not), but my injectors are also at Diamond Diesel right now. The nozzles were all shot. Perhaps I should check for water in the Raycor, too. As to how water can get in the tank, I periodically change the O-ring on the deck cap. It’s incredibly expensive to buy just the single pack at WM, so let me know and I can measure it. If they’re the same and you’re interested in buying in bulk, I could split it with you. As to tank condensation as Camino points out, I have heard this can be a problem. I try to keep my tank filled, but it doesn’t always happen. Usually at the most, however, it only gets about half-way drained before I fill up. There’s also a tank vent on the stern coaming. I try to be careful when hosing off the boat because I’d heard that’s another way water can find its way into the tank.
I have read this too. However, I had my boat for years and years at the Stockton Sailing Club often with only a partial tank of fuel. Never had any issue with water. I did have an issue offshore one time which led me to install the inspection port but in that case I found little balls some paraffin like substance in the bottom of the tank. These would pull up and block the uptake tube. That adventure is recorded on the forum somewhere.
I had forgotten all about the tank vent. Excellent point. I will check that to make sure I haven"t gotten anything going on there. I just washed the boat down before leaving for the race so it could be either of the causes you mentioned. I have not changed the Perko O ring in forever. Shame on me. I would be very interested in sharing a bulk buy. Let me know how we would complete this.
With regard to the race - well, depends on how you measure. You don’t want to look at division or overall results by course, but if you just look at single-handed monohull I came in 9th out of 18 boats which is pretty good for me. I am moving up!
Carliane, By the way, the Corinthian always seems to be a challenge at the finish. You have fluky wind and, in our case, an ebb setting in. Consequently the approach to the line is slow and very hard to judge as the boat moves every which way in the current. Sweet Pea and I were very close for the last hour of the race. We literally finished within two or three seconds of each other (and about 15 feet apart) after five hours of racing. I beat him by a whisker. It was very exciting in an incredibly slow moving kind of way.
Lol I’m dense. You’ve mentioned SSC a few times in posts! I’ve been a member there since I think 1998-9. I haven’t had a boat there in over 6 hrs though except my once a year visit for a week or two. I do go there a lot however (but am not active there) and know only a few people. We should meet for a brew there. Carliane made a good point on the deck fills - when I bought Goodway II the o rings on all the fills were disintegrated. Bought new at wm and keep extras. I used a good amount of marlube on each o ring to keep them more fresh and seal as they should.
The o-rings on the deck fills fail and there is also often water and sediment in the fuel coming off the dock.
Having had to replace a leaking aluminum fuel tank due to water corrosion right after I bought my boat; I don’t want water in my tank or my injectors. I filter all the fuel that goes into the tank through a filter that removes the crud and water. I find a lot of stuff in the filter.
After reading about it in one of Nigel Calder’s books I installed a ball valve in the hose below the diesel deck fill. I keep it closed when I leave the boat at the dock and between taking on fuel during longer cruises. If any water leaks through the deck fill O-ring I swab it out before opening the valve.
Yeah, I don’t want to cut another access port so I crawl into that deep hole to operate the valve. It really isn’t that often. Besides, I’ve built a plywood cover over my relocated water heater installed at the bottom that makes a good platform for access.