Over the holiday weekend I finally got my boat out of the marina for a cruise. Going up the channel I encountered a headwind on my nose so continued to to use my iorn genny (it had been warmed up & running for about 20 mins at about 1600RPM). I then decided to run her a little harder & pushed the throttle up to about 2100RPM. Moments later the RPM kicked up on it's own to aboout 2300 & I noticed an unusual amount of smoke coming out the exhaust (yikes!) I immediately backed off the throttle & went below to check the engine out (the temp was fine at 155). Upon opening the access door I noticed that there was oil splatteres all over the engine compartment, apparently emminating from the breather tube. I inspected the oil & it was black & no indications of water in it. I suspect that I had excessive blow by causing the situation. after easing on the throttle the smoke went away & no further emmisions from my breather tube. The engine ran just fine the rest of the trip, although I am afraid to run her any higher than about 1900RPMs. Any insight to my plight is appreciated! I suspect the engine has about 12-1500 hrs on it (a little smoke upon startup , but then not much at all. I had recently done a complete oil change & filled it to spec with SAE30. Although reading the dipstick has proved difficult... Any ideas on what happened & my next course of action?
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Some ideas
You noted: Although reading the dipstick has proved difficult... My first read was that perhaps your dipstick wasn't reseated properly. Also: "apparently emminating from the breather tube" If you only checked through the little door, you should check some more. U wrote: "it had been warmed up & running for about 20 mins at about 1600RPM..." Uh, don't do that it only harms the engine. Unusual running rpms usually indicate a fuel problem, usually also a filter. Have you checked or replaced your fuel filters recently?
You noted: Although reading the dipstick has proved difficult... My first read was that perhaps your dipstick wasn't reseated properly. Also: "apparently emminating from the breather tube" If you only checked through the little door, you should check some more. U wrote: "it had been warmed up & running for about 20 mins at about 1600RPM..." Uh, don't do that it only harms the engine. Unusual running rpms usually indicate a fuel problem, usually also a filter. Have you checked or replaced your fuel filters recently?
Too much oil?
When reading your post my thought was too much oil. You said you had just changed it, and that reading the dipstick was difficult (I agree!). My guess would be that the higher rpm level caused the oil to be forced out through the breather hose and splattered in the engine compartment. If your breather hose is like mine (I have the same boat/engine) it's routed right next to the air filter/intake. Any oil (liquid or vapor) forced out of the breather hose is subject to getting sucked into the air intake. Diesels like oil, and will burn it just like diesel fuel. In extreme cases, large amounts of oil sucked into an engine can cause a runaway engine (rendering the normal shutdown handle ineffective--stop a runaway by plugging the air intake with a heavy rag). In your case, I'd guess a little bit of oil/vapor got sucked into the intake, and gave you a short rpm boost. Try checking the oil level very carefully, and remove some if you are over filled. In my experience, the M-18 will tolerate a slight overfilling. Any more can cause trouble. Good luck, and please let us know how you make out. Randy
When reading your post my thought was too much oil. You said you had just changed it, and that reading the dipstick was difficult (I agree!). My guess would be that the higher rpm level caused the oil to be forced out through the breather hose and splattered in the engine compartment. If your breather hose is like mine (I have the same boat/engine) it's routed right next to the air filter/intake. Any oil (liquid or vapor) forced out of the breather hose is subject to getting sucked into the air intake. Diesels like oil, and will burn it just like diesel fuel. In extreme cases, large amounts of oil sucked into an engine can cause a runaway engine (rendering the normal shutdown handle ineffective--stop a runaway by plugging the air intake with a heavy rag). In your case, I'd guess a little bit of oil/vapor got sucked into the intake, and gave you a short rpm boost. Try checking the oil level very carefully, and remove some if you are over filled. In my experience, the M-18 will tolerate a slight overfilling. Any more can cause trouble. Good luck, and please let us know how you make out. Randy
Engine discussion forum
You might also want to post your question on the marinedieseldirect.com engine discussion forum. I found lots of great help troubleshooting my M-18 there. I agree with the previous post about oil injestion into the air intake causing temporarily higher rpm. I would also verify the oil level after you are at the dock or mooring for an hour to give the oil a chance to settle. You can check it hot or cold, but be consistant with the same method. I check my oil cold because if I find coolant/water or something else that shouldn't be there, I can deal with the problem before this mixture goes through the engine. Good luck. Let us know how you make out.
You might also want to post your question on the marinedieseldirect.com engine discussion forum. I found lots of great help troubleshooting my M-18 there. I agree with the previous post about oil injestion into the air intake causing temporarily higher rpm. I would also verify the oil level after you are at the dock or mooring for an hour to give the oil a chance to settle. You can check it hot or cold, but be consistant with the same method. I check my oil cold because if I find coolant/water or something else that shouldn't be there, I can deal with the problem before this mixture goes through the engine. Good luck. Let us know how you make out.
Good ideas
I hadn't thought about the air intake getting some of the errant oil (yes it's mounted right next to the intake). With the extra RPMs & smoke "possibly" explained, I'll head up to the boat & check the oil level now that she has sat for awhile. If high oil level doesn't show & give me my answer, then I'll try the other marine deisel forum. Thanks to all! I'll post what I find out.
I hadn't thought about the air intake getting some of the errant oil (yes it's mounted right next to the intake). With the extra RPMs & smoke "possibly" explained, I'll head up to the boat & check the oil level now that she has sat for awhile. If high oil level doesn't show & give me my answer, then I'll try the other marine deisel forum. Thanks to all! I'll post what I find out.
try this
When checking the oil, pull the dipstick out an inch or two and leave it for 3-4 minutes. Then push the dipstick all the way in, remove and read it. My M-18 will always read way low unless I do the above. I guess some sort of pressure builds up preventing the oil from going up the dipstick to the proper level. Hope this helps Steve
When checking the oil, pull the dipstick out an inch or two and leave it for 3-4 minutes. Then push the dipstick all the way in, remove and read it. My M-18 will always read way low unless I do the above. I guess some sort of pressure builds up preventing the oil from going up the dipstick to the proper level. Hope this helps Steve
Low initial readings on oil dipstick
Guys, take a look at the dipstick It has a rubber flange on it. It creates a seal, so when the engien cools down, the dipstick is a plug. That's WHY you need to remove it first, then reinsert before reading.
Guys, take a look at the dipstick It has a rubber flange on it. It creates a seal, so when the engien cools down, the dipstick is a plug. That's WHY you need to remove it first, then reinsert before reading.
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