This is probably a silly question to most, but what transmission oil do I use in our Yannmar 2GM20 trans? I can,t find it in the manual. And while I,am at it, the engine is not starting as well as it once did. I ususally pull the throttel wide open, turn the key and it takes off. Now it takes several tries to get it going. The motor itself is in good shape, its hard starting.
Trans oil
- Thread starter Ron10127
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what transmission?
Check the link attached as it depends on what transmission you have. Also, I'm no expert but it seems logical that the easiest way to kill an engine is to start it at full throttle before the oil can circulate. That's why, at the Yanmar engine classes, they teach that it's a good idea to crank the engine with the stop cable pulled for a few seconds to circulate oil before actually starting it, particularly if it hasn't been run in a while.
Check the link attached as it depends on what transmission you have. Also, I'm no expert but it seems logical that the easiest way to kill an engine is to start it at full throttle before the oil can circulate. That's why, at the Yanmar engine classes, they teach that it's a good idea to crank the engine with the stop cable pulled for a few seconds to circulate oil before actually starting it, particularly if it hasn't been run in a while.
Starting engine
Don't know about this tranny fluid question, but I use full open throttle to start my Yanmar. Once started I quickly throttle back. Regards, Big Joe
Don't know about this tranny fluid question, but I use full open throttle to start my Yanmar. Once started I quickly throttle back. Regards, Big Joe
Yanmar starting
The Yanmars without glow plugs, yes they did make a bunch of them, can only be started when it is cool, or colder at full throttle. Mine flat won't start any other way if the temp is below 50 or there abouts. I always start it with full throttle. But you can quickly pull the throttle back before it gains a lot of RPM. The 2QM in my 1980 S2 is this way, and if it harms it, sure can't tell it. As dependable as an anvil, and never requires much more than regular oil changes.
The Yanmars without glow plugs, yes they did make a bunch of them, can only be started when it is cool, or colder at full throttle. Mine flat won't start any other way if the temp is below 50 or there abouts. I always start it with full throttle. But you can quickly pull the throttle back before it gains a lot of RPM. The 2QM in my 1980 S2 is this way, and if it harms it, sure can't tell it. As dependable as an anvil, and never requires much more than regular oil changes.
2GM20F
The 2GM20F Engine Manual indicates same oil as the engine for the transmission; and the specified Diesel grade oil viscosity varies with outside air temperatures. The level is checked with the dipstick inserted but not screwed in.
The 2GM20F Engine Manual indicates same oil as the engine for the transmission; and the specified Diesel grade oil viscosity varies with outside air temperatures. The level is checked with the dipstick inserted but not screwed in.
Nice n Easy
You are right, my old Yanmar does not have a glowplug. I heard the deal is in order to not need a glowplug it requires a higher compression ratio than glowplugged engines. So I guess the idea is with full throttle it gulps in more air, compresses it, creates heat from the compression and rumbles to life. Then you back off the throttle. Regards.
You are right, my old Yanmar does not have a glowplug. I heard the deal is in order to not need a glowplug it requires a higher compression ratio than glowplugged engines. So I guess the idea is with full throttle it gulps in more air, compresses it, creates heat from the compression and rumbles to life. Then you back off the throttle. Regards.
Here are some things
I've used to make checking the trans oil easier and starting faster on cold days. Unscrew the trans dipstick and clean it. Re-insert it to the top of the threads, but don't screw it down, then pull it out and lay it on a clean paper towel. Sometimes its really hard to see clean trans oil on the dipstick itself, but it will show clearly on a paper towel. Whenever it gets really cold around here and I think my Yanmar may have trouble starting, I run a hair dryer into the air intake for a few minutes before cranking. With the hot air being sucked into the engine, the engine thinks its mid-summer and starts instantly.
I've used to make checking the trans oil easier and starting faster on cold days. Unscrew the trans dipstick and clean it. Re-insert it to the top of the threads, but don't screw it down, then pull it out and lay it on a clean paper towel. Sometimes its really hard to see clean trans oil on the dipstick itself, but it will show clearly on a paper towel. Whenever it gets really cold around here and I think my Yanmar may have trouble starting, I run a hair dryer into the air intake for a few minutes before cranking. With the hot air being sucked into the engine, the engine thinks its mid-summer and starts instantly.
Yanmar hard starting
I used to have to open the throttle on my Yanmar 2QM15 in order to get it started but I cured that problem by removing and having the fuel injectors rebuilt. Not a difficult job and what a difference it has made. Easy starting and good performance underway. My engine is 26 yrs old and I believe that the injectors were never serviced. It's the best thing that I've done to the engine. Good luck!
I used to have to open the throttle on my Yanmar 2QM15 in order to get it started but I cured that problem by removing and having the fuel injectors rebuilt. Not a difficult job and what a difference it has made. Easy starting and good performance underway. My engine is 26 yrs old and I believe that the injectors were never serviced. It's the best thing that I've done to the engine. Good luck!
As always, refer to the service manual
It will tell you precisely the the oil to use in your trans. It could be engine oil or it could be trans fluid. Don't guess and don't go on someone's word. My Yanmar service manual makes no mention of opening the throttle wide open for starting. Your's may say different. I can say with some certainty that diesels have no butterfly valve (because they're fuel injected) and that opening the throttle control only operates the injection pump. It will have no effect on the amount of air a diesel takes in or in the amount of compression it generates. I'll speculate that Rich probably has it right and that one problem with a hard starting diesel could be fouled injectors. My 4JHE (which has no glowplugs) starts with a touch of the key with the throttle at idle. It does it at all temperatures down to near freezing. I'd be very surprised if Yanmar designed any of their diesels needing to be started at WOT. This is all just my experience and I'll go on record that I am NOT an expert.
It will tell you precisely the the oil to use in your trans. It could be engine oil or it could be trans fluid. Don't guess and don't go on someone's word. My Yanmar service manual makes no mention of opening the throttle wide open for starting. Your's may say different. I can say with some certainty that diesels have no butterfly valve (because they're fuel injected) and that opening the throttle control only operates the injection pump. It will have no effect on the amount of air a diesel takes in or in the amount of compression it generates. I'll speculate that Rich probably has it right and that one problem with a hard starting diesel could be fouled injectors. My 4JHE (which has no glowplugs) starts with a touch of the key with the throttle at idle. It does it at all temperatures down to near freezing. I'd be very surprised if Yanmar designed any of their diesels needing to be started at WOT. This is all just my experience and I'll go on record that I am NOT an expert.
Info 2GM20
The 2GM20 is either mated to a Kanzaki KM2C or a KM2P transmission. Design is the same for both transmissions except for the shifting mechanism. Both use motor oil as a lubricant and the recommended viscosity is SAE 10W-30. A change of oil is recommended every 250 hours of operation. My personal opinion is that here is where a top grade synthetic oil shines. It is more heat resistant and maintains viscocity over a longer period of time doubling or tripleting the maintenance schedule. Our H320 equipped with the 2GM20F came from the dealer with ATF in the transmission. No ill effect was noticed except that we would have to add a couple of ounces every 30-50 hours. After checking with the engine manual we contacted the dealer and they still swore that ATF was the correct fluid. Yanmar confirmed motor oil was the correct one but that no damage could be expected from the use of ATF. I gathered that is as long as the proper level is maintained. We switched to synthetic motor oil and have not had a problem with the oil level since.
The 2GM20 is either mated to a Kanzaki KM2C or a KM2P transmission. Design is the same for both transmissions except for the shifting mechanism. Both use motor oil as a lubricant and the recommended viscosity is SAE 10W-30. A change of oil is recommended every 250 hours of operation. My personal opinion is that here is where a top grade synthetic oil shines. It is more heat resistant and maintains viscocity over a longer period of time doubling or tripleting the maintenance schedule. Our H320 equipped with the 2GM20F came from the dealer with ATF in the transmission. No ill effect was noticed except that we would have to add a couple of ounces every 30-50 hours. After checking with the engine manual we contacted the dealer and they still swore that ATF was the correct fluid. Yanmar confirmed motor oil was the correct one but that no damage could be expected from the use of ATF. I gathered that is as long as the proper level is maintained. We switched to synthetic motor oil and have not had a problem with the oil level since.
Our 2GM20F starts at idle throttle every time
We have a 1987 Hunter 31 with about 200 hours on the engine since we added an hour meter in 2000. Don't know what it had on it before 2000. We just turn on the key and push the button with the throttle at idle. It always starts. We took the Mack Boring course in 2000. At their instruction, we have been using 30 weight oil in the tranny since.
We have a 1987 Hunter 31 with about 200 hours on the engine since we added an hour meter in 2000. Don't know what it had on it before 2000. We just turn on the key and push the button with the throttle at idle. It always starts. We took the Mack Boring course in 2000. At their instruction, we have been using 30 weight oil in the tranny since.
Look on the transmission itself
All transmissions shipped with Yanmar engines have a small metal ID tag on them. The tag has model and serial numbers, gear ratios and the type of lubricant required for that unit.
All transmissions shipped with Yanmar engines have a small metal ID tag on them. The tag has model and serial numbers, gear ratios and the type of lubricant required for that unit.
80 W Gear oil
It is a tranny not an engine. The gears need a thing they only put in gear oil called an extreme pressure lubricant. Apparently the gears rub on each other with great force and only a small contact patch so you need something like STP to keep them from wearing. The engine manufacture don't care if the tranny fails. I think if you consult the transmission manual you will find it recommends gear oil or ATF.
It is a tranny not an engine. The gears need a thing they only put in gear oil called an extreme pressure lubricant. Apparently the gears rub on each other with great force and only a small contact patch so you need something like STP to keep them from wearing. The engine manufacture don't care if the tranny fails. I think if you consult the transmission manual you will find it recommends gear oil or ATF.
Bill, different type of trany.
At least on the GM series. They use a cone clutch. Motor oil (or what ever the manual calls for) works just fine. And to Rick Sylvester. You're wrong. You are an expert! At least you sound like one. Good Post!
At least on the GM series. They use a cone clutch. Motor oil (or what ever the manual calls for) works just fine. And to Rick Sylvester. You're wrong. You are an expert! At least you sound like one. Good Post!
Well I put in some time in the automotive world
and over on the land side of things they use gear oil. Not too sure the laws of physics are the same on land and sea but I'll bet they are. For an automatic transmission you use automatic transmission fluid, for a motor you use motor oil, and for a manual gearbox you use gear oil. Almost sounds like the engineers know what they are doing don't it? BTW my transmission manual for my Hurst gearbox says to use gear oil. I believe Hurst is a very common gearbox to find on a sailboat. Now the little tag that Hunter or Yanmar put there (check it out) says to use motor oil, so it looks like you (I know what I'll do) have a decision to make. Gearboxes with planetary haployd gears have a much larger contact patch than "straight" gears do. That is why motor oil will work there. The Hurst has straight gears in it.
and over on the land side of things they use gear oil. Not too sure the laws of physics are the same on land and sea but I'll bet they are. For an automatic transmission you use automatic transmission fluid, for a motor you use motor oil, and for a manual gearbox you use gear oil. Almost sounds like the engineers know what they are doing don't it? BTW my transmission manual for my Hurst gearbox says to use gear oil. I believe Hurst is a very common gearbox to find on a sailboat. Now the little tag that Hunter or Yanmar put there (check it out) says to use motor oil, so it looks like you (I know what I'll do) have a decision to make. Gearboxes with planetary haployd gears have a much larger contact patch than "straight" gears do. That is why motor oil will work there. The Hurst has straight gears in it.
OOOOk,,,,,
You are correct. Gears and 'contact patch' determine the lube to use. But that was my point. The motor oil specs on this trany are from Yanmar, not Hunter. As far as what oil to use in what application your generalities are subject to revision. General Motors spec'd Dexron (ATF) for manual gearboxes behind big engines many years ago. The automatic GearVendors overdrive in my hotrod was originally supplied with gear oil. It's a sun and planetary gearbox. But that lead to delayed cold weather shifts. When I called them about the problem they said "Why don't you Dexron it"? They sent me a lighter spring for the accumulator to be used with the ATF. End of delayed shifts. And as with most stuff, 'it depends'. Most all engines have a thrust bearing locating the crankshaft. They don't do much because when installed in a car the thrust seen by the crank is minimal. But in some racing applications in boats using direct drive, the thrust bearing has all it can handle. In automotive use the axle bearings handle the thrust. Aw, the laws of physics,,,
You are correct. Gears and 'contact patch' determine the lube to use. But that was my point. The motor oil specs on this trany are from Yanmar, not Hunter. As far as what oil to use in what application your generalities are subject to revision. General Motors spec'd Dexron (ATF) for manual gearboxes behind big engines many years ago. The automatic GearVendors overdrive in my hotrod was originally supplied with gear oil. It's a sun and planetary gearbox. But that lead to delayed cold weather shifts. When I called them about the problem they said "Why don't you Dexron it"? They sent me a lighter spring for the accumulator to be used with the ATF. End of delayed shifts. And as with most stuff, 'it depends'. Most all engines have a thrust bearing locating the crankshaft. They don't do much because when installed in a car the thrust seen by the crank is minimal. But in some racing applications in boats using direct drive, the thrust bearing has all it can handle. In automotive use the axle bearings handle the thrust. Aw, the laws of physics,,,
I agree Fred
it depends. The point I'm trying to make is that, since it depends, you should use the type of lubricant that results in long life. Performance is not really an issue as you are not doing a lot of racing with the engine in a sailboat. Shifting, while it may be a little harder, does not effect the operation of the machine as a whole. My engineering instincts tell me that gears need that extreme pressure lubrication to have a long maintenance free life. And since that is what is important to me that's what I use. Same argument for the thrust bearing. It sees tremendous pressure loads and need a proper lubricant. Feel free to use what the manufacturer recommends or not. It's your boat and I'm not going to take offense at your decisions. BTW, my specs where from Hurth (not Hurst as I posted earlier, automotive days flashback!) not Yanmar. For the record, I'd use gear oil in the crankcase if it where not for the fact that it does not play well with the environment around the piston rings. I use motor honey or STP instead. Geee, I wonder why they invented those two products?!?!? Could it be that they know something we don't? Now, if you want to have a REAL debate, lets talk about synthetic vs regular oil. Have a great one Fred, your a great guy
it depends. The point I'm trying to make is that, since it depends, you should use the type of lubricant that results in long life. Performance is not really an issue as you are not doing a lot of racing with the engine in a sailboat. Shifting, while it may be a little harder, does not effect the operation of the machine as a whole. My engineering instincts tell me that gears need that extreme pressure lubrication to have a long maintenance free life. And since that is what is important to me that's what I use. Same argument for the thrust bearing. It sees tremendous pressure loads and need a proper lubricant. Feel free to use what the manufacturer recommends or not. It's your boat and I'm not going to take offense at your decisions. BTW, my specs where from Hurth (not Hurst as I posted earlier, automotive days flashback!) not Yanmar. For the record, I'd use gear oil in the crankcase if it where not for the fact that it does not play well with the environment around the piston rings. I use motor honey or STP instead. Geee, I wonder why they invented those two products?!?!? Could it be that they know something we don't? Now, if you want to have a REAL debate, lets talk about synthetic vs regular oil. Have a great one Fred, your a great guy
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