My new (to me) 1985 O'Day 28 dies when put into gear when engine is at idle speed. It even does this at a few hundred rpm above idle. It pulls well at a very fast idle and goes into gear without complaint. I'm told that most times this is a fuel or fuel delivery problem, so I have cleaned and replaced both fuel filters and have pumped and cleaned the fuel tank. The fuel pump seems fine (I have no way of testing its pressure), and the engine starts and runs well otherwise (with no smoke). I will try fresh fuel in the spring, but assuming that doesn't cure it, I suppose I will consider replacing the injectors, which are 17 years old. However, in talking to the previous owner (only two before me, and a very well maintained boat), I understand that didn't cure the problem and he just worked around it by shifting into and out of gears. Makes for some interesting docking! I'm beginning to wonder is this is just a characteristic of this engine and the torque at slower rpm is just inadequate for the displacement of 10,500 lbs? Has anyone experienced this before, or have any good advice?
O'Day 28 with Universal M12 diesel dies at idle when put under load
- Thread starter John Shropshire
- Start date
Our 28 with the same engine never had that problem, so I don’t think it’s something intrinsic to the model. There is a screen filter in the electric fuel pump you could check if you haven’t already. Also, when you turn the key, before starting the engine, you should hear a tick from the fuel pump about once per second. If it’s more delayed then that it might be a problem with the pump or its screen.
Does the boat have the OEM 2 blade prop or was it increased to something larger? I could imagine being over propped could potentially cause a problem like that, but if that were the case I’d also expect black smoke at higher RPM’s.
Finally - Not sure about your displacement. All the spec’s I’ve seen have the 28 in the mid-7000 pound range, not 10K.
Does the boat have the OEM 2 blade prop or was it increased to something larger? I could imagine being over propped could potentially cause a problem like that, but if that were the case I’d also expect black smoke at higher RPM’s.
Finally - Not sure about your displacement. All the spec’s I’ve seen have the 28 in the mid-7000 pound range, not 10K.
Welcome to SBO, John. You will find lots of great info here as well as others that are willing to help.
I am not at all familiar with your engine, but I am wondering to what speed the idle is set. I could not find an on-line specification for the M12, but I did find a service bulletin that I have attached. Idle speed is typically higher for smaller engines, and the idle range for the larger M3-20B is 1000-1200. So I would think that your engine should be at least in that range or maybe slightly higher. A Universal dealer should be able to tell you exactly what the idle should be. Note in the service bulletin that a low idle could cause stalling. I would check the idle speed with an optical tach- they are inexpensive, often under $20.
I am not at all familiar with your engine, but I am wondering to what speed the idle is set. I could not find an on-line specification for the M12, but I did find a service bulletin that I have attached. Idle speed is typically higher for smaller engines, and the idle range for the larger M3-20B is 1000-1200. So I would think that your engine should be at least in that range or maybe slightly higher. A Universal dealer should be able to tell you exactly what the idle should be. Note in the service bulletin that a low idle could cause stalling. I would check the idle speed with an optical tach- they are inexpensive, often under $20.
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I agrede with Rich about low idle speed as a place to start. Your Hurth transmission is good up to 1400 rpm, but 800 is too low, 1000 plus a tad may get you going (pi!).
Thank you David. I didn’t know about the screen, so I will take the fuel pump apart and check it. It ticks fine, better of course with fully charged batteries. The prop is two blade and it’s original. You are right, 7300 pounds, so 10hp should be plenty, even at idle.
Good, I will get an electronic tach and check it. I’ve been judging by ear which is not very accurate! Thanks Stu.
Thanks Rich, I am happy to be here on SBO, it’s a wonderful resource. I have seen that range somewhere but can’t find it quickly. I will do so and check it with optical tach which I just ordered. I suspect it’s in the range of the larger engines, which may be above what I’ve been using. Great suggestion, thanks!
John, this link may give you some ideas, 'cuz many of them apply to many, many boats:
Critical Upgrades http://c34.org/bbs/index.php/topic,5078.0.html
Thanks Stu, I just looked at the first page and found several things of immediate interest, so it’s going to be quite helpful! This is my first diesel so I’m learning as I’m going....no choice since we have no services on our lake.
I have a Universal M12 diesel. My engine has a Facet electric fuel pump with a replaceable screen.. You can find the screen at Napa.
Thanks Stanley. I’m not sure what pump mine uses, but I will check next time I’m at the lake. I’m curious to know if you’ve experienced the problem I’ve described?
Thanks to your help, I think I may have run the problem down. I removed the original Facet lift pump and took it apart when I got it home. It was very dirty, lots of debris and gunk in the strainer and behind/around the strainer. Due to it's age, I'm going to replace it with new. However, in doing this I noticed a difference in the sequence of lift pump and filters from what my owners manual says it is and the way my boat is actually connected. The manual shows fuel tank to fuel/water separator & filter to lift pump to filter #2 to injector pump to injector, while my boat is actually plumbed from fuel tank to lift pump to fuel/water separator & filter to filter # 2 to injector pump to injector. How is this done on your boat? Does it make any difference? Appreciate any advice you can give. Many thanks.
John, you've answered your own question. Tank to Racor to lift pump is correct. Many, many boats were incorrectly done OEM. Think about what REAL filter you want first...
John:
My M12 engine has a 10 micron racor filter after the tank, then the facet pump with a filter, and then a filter on the engine. I originally had a bronze bodied filter (I believe that it was a Groco and the replacement filters were about $50.00 each) so I replaced it with the Racor housing and 10 micron filter. I have not had any problems.
My M12 engine has a 10 micron racor filter after the tank, then the facet pump with a filter, and then a filter on the engine. I originally had a bronze bodied filter (I believe that it was a Groco and the replacement filters were about $50.00 each) so I replaced it with the Racor housing and 10 micron filter. I have not had any problems.
Your boat is plumbed incorrectly and your manual is correct.
Our ‘85 28 was plumbed from the factory as yours is - lift pump before any filter. As Stu said, that’s really not the way you want it.
My thanks to each of you for your fast response! This is huge, I can't believe the two prior owners didn't catch it and suffered the same problem for years. I'll make the change, see what happens, and let you know. I've heard great things about Racor filters many times. Appreciate your knowledge and wisdom.
Just to follow up with the results: while making these changes I also found that the fuel supply hose that enters the filter on the engine had been put in a bundle of wires that was tightly tied up by a cable tie attached to the ceiling of the engine compartment. It had a medium size kink in it which also appeared to restrict fuel flow. That hose tore apart in my hands with a simple twist. Once the hoses were replaced and the flow corrected (along with a new pump), fuel pumps very well and the engine pulls well at idle and doesn't die. A little tweaking at the injector pump and all is well. Thanks again, sailors!
I have your exact boat. Identical year. Came with no oil water filter, so added. Mine goes Tank, Lift pump, Racor OW filter, but never an issue with that setup. When i got the boat in 1995 it would not idle. Sent the injectors to Yankee Diesel in Danbury, CT and they rebuilt them. Engine idled fine after that, however there were times where it would stall, so I set the idle speed up and that mostly solved. Sometimes after running for an hour or so when I come into the dock it might stall when I go into reverse so I set the throttle up to anticipate this. The Hurth tranny can handle that ok. One thing I recommend is that you adjust your valves if not done lately and change the fuel filter if not already. Small engines can be very sensitive to valve adjustment. This is a terrific little engine and if you keep it in clean fuel, clean your fuel pump sieve annually (replacement not usually necessary), check, drain, replace your Racor OW filter and fuel filter you should should have a good experience. Only time this unit failed me was when it quit a couple of times altogether when the fuel pump ground wire came loose at the pump bracket. This is a lousy setup there with pump secured to the fuel tank wood frame which gets soft and the screws do not hold well. I removed the pump and screwed and glued a PVC block to the wood tank frame, first installing machine screws from the back to the front of the block so the fuel pump bracket is held better and thus than damn ground wire. The engine itself.....bulletproof if you are kind to it.