I've got a 2QM15 in my '81H30. As viewed from the front end, on the right side of the engine (aft of the selenoid)there is a small white plastic fuse box (30A)with two leads coming out from the base. I removed the connected wires the other day, cleaned the male fittings, and fairly quickly forgot which wire went onto which lead at the fuse box. Problem is there are four loose wires with female fittings in the area; two weren't being used anyway. Anyone able to advise me which wire goes where on the fuse box? And while we're at it; does anyone know what the fuse is for? Dumb move I'll hopefully not repeat soon; all guidance appreciated.
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Not much help but..
I've been watching this, certain that someone would respond by now. I can tell you that if I remove that fuse I have no instruments and cannot start the Yanmar. On my H37C, before I repaired a poor ground connection, I occasionally would blow that fuse. I could tell because when I turned on the key none of the gauges came up to zero. Finding that fuse the first time was an experience! Tonight when I go to the boat I'll try to remember to check that wiring. As I remember it now the light colored wire(white?) was on the top male connector. But let me be sure.
I've been watching this, certain that someone would respond by now. I can tell you that if I remove that fuse I have no instruments and cannot start the Yanmar. On my H37C, before I repaired a poor ground connection, I occasionally would blow that fuse. I could tell because when I turned on the key none of the gauges came up to zero. Finding that fuse the first time was an experience! Tonight when I go to the boat I'll try to remember to check that wiring. As I remember it now the light colored wire(white?) was on the top male connector. But let me be sure.
Hi again.
Tried to get the wiring diagram on this HOW site without success. But the diagrams in the Yanmar book are not too helpful. One just shows the wiring harness layout with two wires coming out of the harness and going to that fuse block. I have written a note there that says "20 amps". Then there is a circuit diagram. It shows a red wire coming off one side of the fuse and going to the ignition switch. The other side of the fuse goes to the stud on the starter where the 12V cable attaches. There is no color given but you might be able to discern this from the wires on the starter. I haven't been able to get to the boat to nail this down. I'm guessing that you have resolved this by now.
Tried to get the wiring diagram on this HOW site without success. But the diagrams in the Yanmar book are not too helpful. One just shows the wiring harness layout with two wires coming out of the harness and going to that fuse block. I have written a note there that says "20 amps". Then there is a circuit diagram. It shows a red wire coming off one side of the fuse and going to the ignition switch. The other side of the fuse goes to the stud on the starter where the 12V cable attaches. There is no color given but you might be able to discern this from the wires on the starter. I haven't been able to get to the boat to nail this down. I'm guessing that you have resolved this by now.
Ed
If you want, send me the diagram via email and I'll post it for you. Just include some copy and a caption for it. Sorry you had trouble!
If you want, send me the diagram via email and I'll post it for you. Just include some copy and a caption for it. Sorry you had trouble!
Fuse polarity?
Don't know about this particular boat but fuses aren't normally polarity sensitive. In other words I can't imagine that it makes any difference which wire is connected to which end of the fuse as long as a path for current flow exists.
Don't know about this particular boat but fuses aren't normally polarity sensitive. In other words I can't imagine that it makes any difference which wire is connected to which end of the fuse as long as a path for current flow exists.
Jerry, extra wires are ...
causing Thom the problem. He needs to know which two to attach because there are a couple of extras. With my VOM it would be easy to scope out. Since we haven't heard from Thom I'll try to get to the boat tomorrow evening and sort this out.
causing Thom the problem. He needs to know which two to attach because there are a couple of extras. With my VOM it would be easy to scope out. Since we haven't heard from Thom I'll try to get to the boat tomorrow evening and sort this out.
Back 2 It
Thanks for all the great ideas and offers. I'm going to the boat tomorrow and will make a more detailed sketch so I can describe things more clearly here. Actually my problem is which 2 wires (of the 4) goes to the fuse box and (does it matter)which wire goes to which pole? I really appreciate the efforts you folks are giving this. Stay tuned.
Thanks for all the great ideas and offers. I'm going to the boat tomorrow and will make a more detailed sketch so I can describe things more clearly here. Actually my problem is which 2 wires (of the 4) goes to the fuse box and (does it matter)which wire goes to which pole? I really appreciate the efforts you folks are giving this. Stay tuned.
The Rest of the Story
"Fresh" from a day's labors in the boatyard, here's what I see as my wire options. There are in fact 5 wires with female spade clips exiting midway in the harness that comes back from the alternator; the two I took off the fuse box and need to reattach, plus 3 others! (Maybe they've been multiplying while I've been away?) Only one of the 5 wires originates at the alternator and EXITS at this juncture; I'll call that Red1. The other four ENTER the harness at this same midsection and exit a foot later at their terminus on one of two plug connectors. One of the connectors (A)has 5 wires terminating here and the other (B)has 3. The four wires (not counting Red1)ENTERING the harness at this point, are Orange, Blue, Red(#2), and Brown. The Blue and Orange wires go to connector B and the Red2 and Brown go to connector A. I've located the wiring schematic in my Yanmar Operator's Manual; it's indicating two red wires connect to this fuse--one each originating with the starter motor and the alternator. And, believe it or not, each of the red wires has a tiny collar (real, real tiny)on it that says "fuse". Could this be the solution? It appears the other colored wires should be connected to various engine sensors. Additional ideas?
"Fresh" from a day's labors in the boatyard, here's what I see as my wire options. There are in fact 5 wires with female spade clips exiting midway in the harness that comes back from the alternator; the two I took off the fuse box and need to reattach, plus 3 others! (Maybe they've been multiplying while I've been away?) Only one of the 5 wires originates at the alternator and EXITS at this juncture; I'll call that Red1. The other four ENTER the harness at this same midsection and exit a foot later at their terminus on one of two plug connectors. One of the connectors (A)has 5 wires terminating here and the other (B)has 3. The four wires (not counting Red1)ENTERING the harness at this point, are Orange, Blue, Red(#2), and Brown. The Blue and Orange wires go to connector B and the Red2 and Brown go to connector A. I've located the wiring schematic in my Yanmar Operator's Manual; it's indicating two red wires connect to this fuse--one each originating with the starter motor and the alternator. And, believe it or not, each of the red wires has a tiny collar (real, real tiny)on it that says "fuse". Could this be the solution? It appears the other colored wires should be connected to various engine sensors. Additional ideas?
My Final Answer?
Probably not, but here goes. Went to the boat last night. My H37C wiring harness actually looks like the one in the Yanmar manual! I have four wires exiting near the fuse box. Two are red and actually are labelled, "FUSE". These both attach to the fuse holder, either one to either post. The other two are orange and blue. They go to what looks like a pressure sending unit(small, round, and screwed into the block) but my wiring diagram shows it as the tachometer sending unit. This is relatively close to the fuse holder. The diagram I have of the cable routing does show another, longer, wire going to the water temp sender. In the wiring diagram that wire is BROWN. That sender unit will have just one post on it. Hope this does it. Ed
Probably not, but here goes. Went to the boat last night. My H37C wiring harness actually looks like the one in the Yanmar manual! I have four wires exiting near the fuse box. Two are red and actually are labelled, "FUSE". These both attach to the fuse holder, either one to either post. The other two are orange and blue. They go to what looks like a pressure sending unit(small, round, and screwed into the block) but my wiring diagram shows it as the tachometer sending unit. This is relatively close to the fuse holder. The diagram I have of the cable routing does show another, longer, wire going to the water temp sender. In the wiring diagram that wire is BROWN. That sender unit will have just one post on it. Hope this does it. Ed
Yanmar Service Manual
Thom, I'd be glad to fax you the pages from my Yanmar 2QM15 Service Manual if you need it just e-mail me a fax number. Maybe you already have it? I was looking at diagrams on pages 10-1 and 10-2.
Thom, I'd be glad to fax you the pages from my Yanmar 2QM15 Service Manual if you need it just e-mail me a fax number. Maybe you already have it? I was looking at diagrams on pages 10-1 and 10-2.
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