The engine on our 1987 Hunter 34 - 24hp Yanmar 3GMF - has a difficult time starting if it hasn't been used in a couple of days. Once she runs for a while and then we sail for a while and then go to fire it back up, it will start right up really smoothly. Basically, for the first start, I have to hold in the start button for 10 seconds or so with 1/2-2/3 throttle and it starts kind of choking a little bit for about 5 seconds plus and then revs up smoothly and I then throttle it back down to idle. A bit of smoke comes out of the exhaust during this time as well - mostly white smoke, but the first time I did this I was chicken to hold the start button that long and after about 4 tries, some black smoke came out of the exhaust. I have pretty much only started the engine when the air temps. have been around 60-70 degrees F. Being that I am new to inboards (had a 25 footer with an outboard until a month ago), I am not sure if this is normal or not. Is it? If not, where should I look first? During the survey, the fuel filter looked clean and I have a full tank of deisel. Also, anyone know of a book like "Deisel for Dummies" or something so that I can learn what I need to know? Thanks.
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Yannies are cold blooded
Yanmars don't have glow plugs so they are always hard to start in cool weather. You've got the drill down and you are right about not running the starter for long bursts. Don't use any starter fluids. Some say holding a hair dryer to the air intake for a few minutes helps.
Yanmars don't have glow plugs so they are always hard to start in cool weather. You've got the drill down and you are right about not running the starter for long bursts. Don't use any starter fluids. Some say holding a hair dryer to the air intake for a few minutes helps.
Sluggish Starting
Your sluggish starting problems could be a number of things hard to diagnose from afar. But I keep my boat on the Bay not too far from you and, as we know, it's been getting nippy -- last night it dropped below freezing here. Cold weather is always going to make starting a bit harder. So...I assume you've got fully charged batteries and all the connections are tight and clean. I also assume you've added the right stuff to your fuel to stabilize it and keep it from gelling when cold. If all is well with your engine, that is there really is nothing wrong with it other than the cold weather, try this: Plug an electric hair dryer into shore power and let it run in your engine compartment for a few minutes. When you get ready to start the engine, try to focus the output of the dryer toward the air intake on the engine. Hit the starter and see what happens. My boat will start right up. BTW, if you have to hold the starter button down for more than 15 seconds or so, close the raw water intake seacock first to prevent water backing up into your engine. Remember to open it again as soon as the engine starts.
Your sluggish starting problems could be a number of things hard to diagnose from afar. But I keep my boat on the Bay not too far from you and, as we know, it's been getting nippy -- last night it dropped below freezing here. Cold weather is always going to make starting a bit harder. So...I assume you've got fully charged batteries and all the connections are tight and clean. I also assume you've added the right stuff to your fuel to stabilize it and keep it from gelling when cold. If all is well with your engine, that is there really is nothing wrong with it other than the cold weather, try this: Plug an electric hair dryer into shore power and let it run in your engine compartment for a few minutes. When you get ready to start the engine, try to focus the output of the dryer toward the air intake on the engine. Hit the starter and see what happens. My boat will start right up. BTW, if you have to hold the starter button down for more than 15 seconds or so, close the raw water intake seacock first to prevent water backing up into your engine. Remember to open it again as soon as the engine starts.
injectors?
I had similar problem with my 3GM30F in April. Injectors were bad. Had them popped at local Yanmar dealer. Both spray pattern and springs on all three injectors were bad. Replaced the injectors. Now no starting problem.
I had similar problem with my 3GM30F in April. Injectors were bad. Had them popped at local Yanmar dealer. Both spray pattern and springs on all three injectors were bad. Replaced the injectors. Now no starting problem.
Easy fix
Keep a hairdryer on board and use shorepower to blow it into the intake horn for 10 minutes. Presto!
Keep a hairdryer on board and use shorepower to blow it into the intake horn for 10 minutes. Presto!
compression?
Could be normal cold weather or you could be a little low on compression in one or more cylinders. If the engine has ever been hydolocked it's possible one of the rods is bent and reducing compression in a cylinder such that it doesn't want to fire unless the engine is hot. If the hair dryer trick doesn't work you might want to run a compression check.
Could be normal cold weather or you could be a little low on compression in one or more cylinders. If the engine has ever been hydolocked it's possible one of the rods is bent and reducing compression in a cylinder such that it doesn't want to fire unless the engine is hot. If the hair dryer trick doesn't work you might want to run a compression check.
One more idea,
Try different throttle settings too. Such as full throttle. Mine's calibrated that way. (It's a fuel pump thing)
Try different throttle settings too. Such as full throttle. Mine's calibrated that way. (It's a fuel pump thing)
Same Problem - Easy Fix
Jared, I've got the same engine and here's the tips I got here on HOW a few years ago. I only have this problem when it's cold. If you're having it at other times you may have other issues to deal with. A the slip: While I'm plugged into shore power I have a small electric heater onboard. I simply pull the stairs out or open the engine cover and direct the heat at the engine for 5-10 minutes. I then go about doing other things, come back in 5-10, hit the starter, and over she goes. Never a problem. On the hook when it's cold: Again, I got this tip here on HOW and have used it several times with success. Open the first cylinder lever on the top of the engine then push the start button. I only do this if it's cold, I'm not on shore power, and she's having trouble turning over. Releasing the compression on that first cylinder helps to get the engine going when it's cold. Once she turns over I simply close down the lever. As far as the smoke goes I just had my engine looked at last week by Hartge's Yard in Galesville. One of my questions was about the engine smoking at startup after a layoff of 10 or more days. The mechanic told me that was normal after a 10-14 days as long as it was just for a few moments and just at startup. Hope this helps. Joe
Jared, I've got the same engine and here's the tips I got here on HOW a few years ago. I only have this problem when it's cold. If you're having it at other times you may have other issues to deal with. A the slip: While I'm plugged into shore power I have a small electric heater onboard. I simply pull the stairs out or open the engine cover and direct the heat at the engine for 5-10 minutes. I then go about doing other things, come back in 5-10, hit the starter, and over she goes. Never a problem. On the hook when it's cold: Again, I got this tip here on HOW and have used it several times with success. Open the first cylinder lever on the top of the engine then push the start button. I only do this if it's cold, I'm not on shore power, and she's having trouble turning over. Releasing the compression on that first cylinder helps to get the engine going when it's cold. Once she turns over I simply close down the lever. As far as the smoke goes I just had my engine looked at last week by Hartge's Yard in Galesville. One of my questions was about the engine smoking at startup after a layoff of 10 or more days. The mechanic told me that was normal after a 10-14 days as long as it was just for a few moments and just at startup. Hope this helps. Joe
Cold Starting
I have similar problems on my '88 Hunter 35. Cold starts are only a problem after sitting for several days. The following solution was suggested a few days ago by a Yanmar dealer source that I trust - but I have yet to try it. The problem is apparently reduced compression on an old engine. Oil on the cylinder walls normally helps to seal the piston rings and keep up the compression. After a long sit - the oil has all drained away into the sump. There are two versions of this solution. One is to drill a small hole in the inlet manifold, just behind the air filter, in order to install a tube that then can be used to pour in a little oil into the manifold just before starting. The easier one to try is to remove the air filter and spray some WD-40 straight into the inlet manifold. Both solutions apparently coat the cylinder walls with oil, increasing the compression and solving the starting problem...... or so I am told!! I really like Warren's idea of closing the raw water intake sea cock, until she fires up, in order to prevent an engine catastrophy should sea water flood back into the engine from the muffler/mixing elbow after excessive engine cranking.
I have similar problems on my '88 Hunter 35. Cold starts are only a problem after sitting for several days. The following solution was suggested a few days ago by a Yanmar dealer source that I trust - but I have yet to try it. The problem is apparently reduced compression on an old engine. Oil on the cylinder walls normally helps to seal the piston rings and keep up the compression. After a long sit - the oil has all drained away into the sump. There are two versions of this solution. One is to drill a small hole in the inlet manifold, just behind the air filter, in order to install a tube that then can be used to pour in a little oil into the manifold just before starting. The easier one to try is to remove the air filter and spray some WD-40 straight into the inlet manifold. Both solutions apparently coat the cylinder walls with oil, increasing the compression and solving the starting problem...... or so I am told!! I really like Warren's idea of closing the raw water intake sea cock, until she fires up, in order to prevent an engine catastrophy should sea water flood back into the engine from the muffler/mixing elbow after excessive engine cranking.
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