I bought a boat that has a Yanmar 20 HP 3GMF motor in it. I have NO idea what size battery is proper for this motor. I'm in the south, so HOT days are something to effect battery size. I know bigger may be better but I want to know what was (or should be) used. Anyone know what CCA or MCA I would need to use for this motor???? Also wondering if a car battery with that amout of CCA would work and if not, WHY not??????
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yanmar's site
I was at Yanmars site ( http://www.yanmarhelp.com/i_elect.htm ) and under electrical, it said all GM type motors need only 200 CCA. SDounds kind of low to me. Maybe I'm reading it wrong though.
I was at Yanmars site ( http://www.yanmarhelp.com/i_elect.htm ) and under electrical, it said all GM type motors need only 200 CCA. SDounds kind of low to me. Maybe I'm reading it wrong though.
Marine environment
The Yanmar will draw only what is needed to turn the starter. Like cubic inches or horse power, nothing like CCAs. Go big. I would recommend gel (check your charger for compatibility) and a marine designed battery package (stainless steel connections).
The Yanmar will draw only what is needed to turn the starter. Like cubic inches or horse power, nothing like CCAs. Go big. I would recommend gel (check your charger for compatibility) and a marine designed battery package (stainless steel connections).
Yanmar wrote me
FYI: I just got a letter from someone at Yanmar. He said, that motor (& all GM models) only need a 200 CCA battery. Just seemed small to me. He also said a car battery is fine unless you're in rough water a lot.
FYI: I just got a letter from someone at Yanmar. He said, that motor (& all GM models) only need a 200 CCA battery. Just seemed small to me. He also said a car battery is fine unless you're in rough water a lot.
not a 30F
I never said I had a 3gm30F. I said I had a 20HP 3gmf. It's a 3GMF rated at 20 HP continous and 22.5 HP at 3600 RPM for 1 min. max.
I never said I had a 3gm30F. I said I had a 20HP 3gmf. It's a 3GMF rated at 20 HP continous and 22.5 HP at 3600 RPM for 1 min. max.
R.S. we're confused, how many cylinders?
Sounds like your new to this stuff. Bob is right. If you don't use your start battery for house bank duty just stick in any thing that will fit. Any type will do too. Meaning a car battery (cheap) is fine. You might need adapters for your terminals. This is DC electricity, not `rocket' you know what. Oh, when you said 3gm__, that means your Yanmar is a 3 cylinder engine. I've not heard of a 20hp Yanmar with three cylinders. If you have a 3gm__, then it's 26hp continous, 27hp momentary (10 min.)
Sounds like your new to this stuff. Bob is right. If you don't use your start battery for house bank duty just stick in any thing that will fit. Any type will do too. Meaning a car battery (cheap) is fine. You might need adapters for your terminals. This is DC electricity, not `rocket' you know what. Oh, when you said 3gm__, that means your Yanmar is a 3 cylinder engine. I've not heard of a 20hp Yanmar with three cylinders. If you have a 3gm__, then it's 26hp continous, 27hp momentary (10 min.)
three quarters dead
It doesn't take much to start these little yanmars I ran my battery down once and the first try wouldn't start it but waited five minutes and off it started. I keep the start battery seperate from house battery which I got at sears and never have any problems,bigger for the house bank but small is ok for start battery
It doesn't take much to start these little yanmars I ran my battery down once and the first try wouldn't start it but waited five minutes and off it started. I keep the start battery seperate from house battery which I got at sears and never have any problems,bigger for the house bank but small is ok for start battery
I have a 3GMF that starts instantly.........
..every time I push the button. Consequently, I leave the switch on house all the time, and only use the starting battery at the dock to check it's still there. I've gone two days using the radio, wheel pilot, GPS, lights, etc. and still could start with the house bank ('though it did take a little coaxing).
..every time I push the button. Consequently, I leave the switch on house all the time, and only use the starting battery at the dock to check it's still there. I've gone two days using the radio, wheel pilot, GPS, lights, etc. and still could start with the house bank ('though it did take a little coaxing).
Attachments
I have a discusion about batteries on our,,
web site along with our rebuild. Actually just a blurb or two.
web site along with our rebuild. Actually just a blurb or two.
3 cylinder 20 hp. 3gmf
It is a 3 cylinder 3 GMF aka 3 GM(F) rated at 20 hp and 22.5 at limited 3600 rpm for 1 min.. It's a great small motor and there are many around. BTW, I went with a 780 MCA starting battery. Thanks everyone
It is a 3 cylinder 3 GMF aka 3 GM(F) rated at 20 hp and 22.5 at limited 3600 rpm for 1 min.. It's a great small motor and there are many around. BTW, I went with a 780 MCA starting battery. Thanks everyone
To R. S. thank you!
Sea trials are going well. Only problem so far is the Max Prop is now a little UNDER pitched. Oh well, we can live with it until next haul out. Another revelation, in books like 'This Old Boat', etc, an old adage is 'all yachts squeak and/groan. Well,,, so far,,, under sail the sound in the main cabin is only that of water on the hull. I used polyurethane to bed the bulkheads. Home Depot sells 'em for $3.00 a tube.
Sea trials are going well. Only problem so far is the Max Prop is now a little UNDER pitched. Oh well, we can live with it until next haul out. Another revelation, in books like 'This Old Boat', etc, an old adage is 'all yachts squeak and/groan. Well,,, so far,,, under sail the sound in the main cabin is only that of water on the hull. I used polyurethane to bed the bulkheads. Home Depot sells 'em for $3.00 a tube.
To R.S.(and all) here's our new (er) web address
about our rebuild. That last link I posted is toast. http://members.tscnet.com/pages/ss427/EpitomesRebuild.html
about our rebuild. That last link I posted is toast. http://members.tscnet.com/pages/ss427/EpitomesRebuild.html
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