I have a 35.5 legend 1993 with a 3 GM diesel engine 28 horse. I have trouble starting it in weather below 65 degrees. I have no trouble starting when it is warm. What could the problem be? Thanks for you help.
Hard starting when cold-3GM diesel Yanmar
- Thread starter catawbarod
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Yanmars do not have a glow plug. They rely on compression to build up heat to burn the fuel. It is normal to experience a delay of a few revolutions to start the engine when cold. More than a few and your compression may not be up to par. If the engine is running good I would say , live with it.
Need some more info, Rod.. some discription of what is happening and what it sounds like.. Is it turning over OK with the starter? Is the starter speed ok? does it spit or cough.. does it smoke a lot when it does start? Does it have to spin a long time before firing? Lotsa hours on it? valves set correctly? Recent devlopment or something that happened after work on the engine? fresh diesel?
Not trying to badger ya, just need some discription about what you are seeing. There are a few guys on the forum that will help if you can give a bit more info. A phone recording file of it trying to start would be a help.. How cold is cold? or what is the temp where it has a tough time starting? This engine usually does not have a starting problem other than the starter not spinning it.. We started one Saturday that had been sitting for 9 months; it fired on the second revolution.
Not trying to badger ya, just need some discription about what you are seeing. There are a few guys on the forum that will help if you can give a bit more info. A phone recording file of it trying to start would be a help.. How cold is cold? or what is the temp where it has a tough time starting? This engine usually does not have a starting problem other than the starter not spinning it.. We started one Saturday that had been sitting for 9 months; it fired on the second revolution.
cold start
my tired old (1982 + many hours) 1GM also does not come to life easily in cold weather. If
I release the starter to soon the engine runs backward and fills the cabin with smoke. I finally accepted that I do not start a car but a boat diesel. So now I'm prepared to crank my starter
for 10-15 seconds at a time at relatively low throttle. It may not catch on first go but I can sort of sense when the motor will continue to run. So far I've been ok eventually thanks to a good starting battery.
my tired old (1982 + many hours) 1GM also does not come to life easily in cold weather. If
I release the starter to soon the engine runs backward and fills the cabin with smoke. I finally accepted that I do not start a car but a boat diesel. So now I'm prepared to crank my starter
for 10-15 seconds at a time at relatively low throttle. It may not catch on first go but I can sort of sense when the motor will continue to run. So far I've been ok eventually thanks to a good starting battery.
Compression
As I understand the engine, the more throttle/air you give the engine the more compression. I have to crank my old 1980 engine a while to get it going in the cool months. Having the engine at more throttle seems to start it o.k. Saying this I agree with G. Meyer, after turning it over a few times you can tell when it is about to start and then keep turning it over until it does.
As I understand the engine, the more throttle/air you give the engine the more compression. I have to crank my old 1980 engine a while to get it going in the cool months. Having the engine at more throttle seems to start it o.k. Saying this I agree with G. Meyer, after turning it over a few times you can tell when it is about to start and then keep turning it over until it does.
An old trick in cold weather...
is to point a running hair dryer at the air intake with the compression levers lifted, then have someone hit the starter button. Close a compression lever after a few revs and hope the dryer has raised the intake air temp enough to fire off the cylinder in compression. If it fires, close the other levers.
is to point a running hair dryer at the air intake with the compression levers lifted, then have someone hit the starter button. Close a compression lever after a few revs and hope the dryer has raised the intake air temp enough to fire off the cylinder in compression. If it fires, close the other levers.
Some Diesel motor notes…. Diesels do not have a “throttle” that limits air into the engine as gasoline motors do. They always take a full gulp of air on each revolution. The “throttle” that controls speed, changes an RPM target in the governor, which then adjusts the injection pump volume to make the motor speed up or slow down to meet that target. Sooooo pushing the throttle up adds a tiny bit more fuel, but since the motor is already way below RPM target, the governor will have opened the fuel up pretty far already. But do use ½ to ¾ throttle so that when it does start it will get a bunch of fuel… Be ready to reduce quickly. Some other brands of diesel motors have glow plugs and some have a cold start device that adds more fuel just for starting, and some have both of these features.. The Yanmars that I am familiar with have none of these features but generally start pretty well.. That said, where my boat is, the minimum start temperature is about 45F.. because the water never gets much colder than that here.. and is typically more like 60F in the winter. No cold start problems.
Try the decompression lever
At cool temperatures you have thick oil, cold air, batteries that are struggling and more friction due to everything being cold. Try getting the engine up to speed by activating the decompression lever while she cranks. Once the starter had her turning let go of the lever and she should start right up.
As always don't crank for more than 15 second with out letting the starter motor cool for at least a minute to prevent burning the wire out of it. The blow dryer trick works well too but is not much help on a cool morning at anchor.
At cool temperatures you have thick oil, cold air, batteries that are struggling and more friction due to everything being cold. Try getting the engine up to speed by activating the decompression lever while she cranks. Once the starter had her turning let go of the lever and she should start right up.
As always don't crank for more than 15 second with out letting the starter motor cool for at least a minute to prevent burning the wire out of it. The blow dryer trick works well too but is not much help on a cool morning at anchor.
Thank all of you for taking an interest in my issue of hard starting when cold. to answer Claude....is it turning over ok and is speed good--yes, does it spit, cough and and smoke alot when it starts--yes (reminds me of a girl I once dated), spin a long time before firing--yes, lots of hours on engine--no, new development--no, fresh diesel--yes. I sail on lake Erie. boat is in the water in May (cool) and stays in until late Oct. (cool). When it is I would say 65 and lower, the starter will turn very well but takes a minute or 2 to start. I have be giving it a lot of throttle while starting. When it does start, and it always does eventually, a big bellow of smoke poors out of the engine. Then, once the smoke clears, it runs fine. In warmer weather, it starts on the first revelution. When I put the boat up in October of last year. It was 55 degrees. I put a heater on in the cabin over night to insure a good and it worked. Started right up. I guess what I can do is move to Florida.
Thanks,
Rod
Catawba Island
Pot Clinton Ohio.
Thanks,
Rod
Catawba Island
Pot Clinton Ohio.
Hey Rod
My 1987 hunter 34 had the same engine...same problem...it was really wierd...hard starting when cold...and when it was warm it started instantly....never did figure it out...i sold my 34 after 9 yrs of ownership...i now have two cape dorys...a typhoon and a 22 footer...
My 1987 hunter 34 had the same engine...same problem...it was really wierd...hard starting when cold...and when it was warm it started instantly....never did figure it out...i sold my 34 after 9 yrs of ownership...i now have two cape dorys...a typhoon and a 22 footer...
rotella 15w-w40 always worked for me
i switched to rotella oil several seasons ago, and only change back to straight 30w for the summer season. i use my h34 all winter, and starting is no problem. when the weather moderates alittle i go sailing, and 2 fresh 27 batteries are essential. my engine box temp is usually in the 40 +/- degrees due to the outside water temp. its pays to treat the fuel every month with moisture, and algae preventer, and i also have to mention a splash of marvel mystery oil, and octane boost helped for all these years. you can shine a flashlite into the racor fuel filter, and make sure you have clean pink fliter paper. if not its probably restricting flow to the engine. make sure you use the decompression lever for 4 seconds to flush the bearings with oil before starting. throttle opened about 1.5" works for me everytime.
i switched to rotella oil several seasons ago, and only change back to straight 30w for the summer season. i use my h34 all winter, and starting is no problem. when the weather moderates alittle i go sailing, and 2 fresh 27 batteries are essential. my engine box temp is usually in the 40 +/- degrees due to the outside water temp. its pays to treat the fuel every month with moisture, and algae preventer, and i also have to mention a splash of marvel mystery oil, and octane boost helped for all these years. you can shine a flashlite into the racor fuel filter, and make sure you have clean pink fliter paper. if not its probably restricting flow to the engine. make sure you use the decompression lever for 4 seconds to flush the bearings with oil before starting. throttle opened about 1.5" works for me everytime.
lots of fuel
My boat stays in the water year round in Vancouver and its fairly cold here. I find if I start it with 3/4 to full throttle and keep my hand on the throtle and power back immediately it starts right away.
If you have lots of time you can always open the engine compartment and let an electric heater blow directly in and warm it up.
My boat stays in the water year round in Vancouver and its fairly cold here. I find if I start it with 3/4 to full throttle and keep my hand on the throtle and power back immediately it starts right away.
If you have lots of time you can always open the engine compartment and let an electric heater blow directly in and warm it up.
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