If you happen to see small black specks (like pepper) coming out the exhaust or floating on the water behind the boat, you could have a clogged mixing elbow or exhaust riser. There are also other sources of exhaust restrictions. Although rare, I have seen the inside of wet exhaust hose deteriorate and block the hose. And most Catalinas use an exhaust riser, while Ericson and some O'Days use an elbow. Personally, the elbow is a cooler, simpler, cheaper alternative to the rinky dink exhaust on my Universal.
Diesel Problem Smorgasbord...
- Thread starter Jtcf78911
- Start date
I doubt the riser is a problem, since it seemed to have developed fairly rapidly. And my experience with overheated Kubutas is that they tend to run BETTER when overheated (until they seize...) - I had cooling problems on my M-25 and it was often so hot the paint was smoking, and the only indication was the temp gauge.
I'd bet a coffee it's an (intermittent?) air leak in the fuel line. Kubutas (unlike Yanmars) are very tolerant of some air, coughing and sputtering (and blowing black smoke) but soldiering on. In other words, pretty much exactly as the OP described. If the return line is piped to the filter instead of back to the tank, the air bubbles keep re-circulating.
The other likely suspect is the high-pressure pump. Not getting enough pressure to the injectors results in bad performance, black smoke... and if it's something intermittent, it could explain the observations.
druid
I'd bet a coffee it's an (intermittent?) air leak in the fuel line. Kubutas (unlike Yanmars) are very tolerant of some air, coughing and sputtering (and blowing black smoke) but soldiering on. In other words, pretty much exactly as the OP described. If the return line is piped to the filter instead of back to the tank, the air bubbles keep re-circulating.
The other likely suspect is the high-pressure pump. Not getting enough pressure to the injectors results in bad performance, black smoke... and if it's something intermittent, it could explain the observations.
druid
It's crap in tank clogging pick up tube you could go to auto parts store and buy an inline vacume gauge and test that or pull pickup tube up out tank and see all crud on little filter end or it could be any of other filters or pump but fuel prob for sure
This is from the previous owner - very nice guy and I think trustworthy.
"The injectors were completely rebuilt in.... 2008 or 9 and should be ok.. Remember to watch for dark sooty exhaust. This happens when you push the throttle all the way forward when steaming. You are giving the engine more fuel than it can use. The result is unburned fuel (soot). It will turn the transom black and carbon up the injectors and exhaust riser."
My transom certainly was black by end of trip - and god only knows what my injectors are looking like..
Tx. for any additional thoughts.
Tom O'Day 28
"The injectors were completely rebuilt in.... 2008 or 9 and should be ok.. Remember to watch for dark sooty exhaust. This happens when you push the throttle all the way forward when steaming. You are giving the engine more fuel than it can use. The result is unburned fuel (soot). It will turn the transom black and carbon up the injectors and exhaust riser."
My transom certainly was black by end of trip - and god only knows what my injectors are looking like..
Tx. for any additional thoughts.
Tom O'Day 28
I run my M-12 at about 80% throttle (my estimate as no tach) and do not see soot all season. You really should not run it flat out anyway, even though this engine is a tiny bit undersized for the 28. Again, I really think you need to check that fuel pump strainer. Take you all of 2 minutes to twist it off, check, clean and replace. If it is like mine, the pump looks like this. Put an adjustable wrench on the underside of it and twist off the bottom bayonet-type fitting. Put your finger up there and pull out the strainer. If that is really gummed up, won't matter how good the filters down the line are.
Got burned today by an old nemesis. Engine quit out of clear blue. Re-started for 10 second failed again etc. Finally dawned on me I had this problem years and years ago. The damn ground cable on the fuel pump. O'day mounted the fuel pump to the fuel tank box with wood screws, one of which captures the ground wire. Vibrations loosen the mounting and with it the ground. Re-tighten screw all good until next time. I am going to re-do all this with a proper metal mounting plate. machine screws and lock nuts as this is nothing but a blood pressure-raiser. You might have a look at that ground also, could be corroded or loose. Cannot easily see from the quarter berth, so go down into the deck hatch with a flash light.
Same rig in my boat - metal mounting plate probably a good idea. A lot of continuous vibration going on at that spot. Have now replaced fuel pump and fuel injectors (rather inexpensively I'd say - just bumps, cuts and grease), bled system and treated fuel. Idling well at base and high throttle and will take it out for real on Sunday. Crossing my fingers. Tx. for the thoughts. Tom.
Hope you hear the happy ticking of the fuel pump above all. No, acatually the diesel drowning out the happy ticking....
Happy to say today went off without a hitch. Engine started and ran well and I didn't even see the black crap coming out of exhaust - of course I did stay clear of full throttle - no more of that. Beautiful sailing day with winds 12-20 knots. Tx. to all for advice and guidance on the diesel front. Feel like I really learned-accomplished something. Best. Tom.
Great news. Happy for you. So, presumably you checked a lot of stuff that a number of us suggested. What is your sense as to what the issue was? I mean, did you see anything out of whack at all???
[QUOTE="...- of course I did stay clear of full throttle - no more of that. .[/QUOTE]
Full throttle should be doable- and be done- once in a while. I do it every time I go out of the creek and into the Severn. If I can make 3500 and 7.2, I know that all is okay.
Full throttle should be doable- and be done- once in a while. I do it every time I go out of the creek and into the Severn. If I can make 3500 and 7.2, I know that all is okay.
Fair point. And keep in mind that black exhaust will also occur with an increase of rpms. Just look a trucks and buses pulling away from stop lights. Short of full throttle you should not see it constantly however....at least I don't.
The injectors I pulled were rebuilt 6 years previous to my purchase. I don't know what the heads should have looked like - but these looked very sooty - so would not be surprised if some fouling had occurred. On pulling fuel pump I did notice what may have been a small crack in the incoming fuel line at point of pump connection - so maybe an air leak. Also noted that the new fuel pump seems to be cranking louder and faster than the one I removed. So back to who knows? I only know it's now working and that I saved big $$$$'s and gained experience by doing the repairs myself. As for full throttle, I should have said "extended periods" of full throttle..like the 8 hours I put on her when coming down from Portland, ME. Problems started just at the conclusion of that trip. And yes, all good advice I'm getting on this site, though sometimes some sifting is required. Tx. again Sailboat Owners. T.
Of those things, my money is on the fuel pump issue......key thing is you should now have a nice summer.....
Wishing you the same. I stopped drinking while underway many, many years ago and I also do not serve same to guests. Plenty of time for that after the anchor gets (properly) set. Anything else too risky.
To OP, based on the age of all our boats you should probably replace all of your fuel lines, it is recommended they get replaced every ten years (the rubber lines). I learned this the hard way, so speaking from experience a few years back I found some fuel in the bilge and eventually located the source as a split in a rubber fuel line, the fuel would flow along the hose and drip down in a spot where it wasn't visible, so it was hard to find. You can get fuel line by the foot at a NAPA store (or equivalent) and it is a snap to replace so you might want to look at that if it hasn't been done in say 30 years.