I would like to install a tachometer on my Yanmar 3QM30. An optional tachometer is available from the Yanmar along with a tach sensor. I have looked through the service manual carefully and cannot find where the sensor would be installed. Has anyone installed the tach and sensor? Any tips before I dive into buying and installing one?
- Status
- Not open for further replies.
E
Ed Schenck
Alternator?
My panel and tach are the VDO brand. It attaches to a post on the alternator. I don't think it even requires a sensor. My Yanmar manual(2QM20/3QM30) is on the boat but I have attached the basic wiring diagram from the manual. I do not know where that sensor screws in exactly but is has to be over the flywheel somewhere.
My panel and tach are the VDO brand. It attaches to a post on the alternator. I don't think it even requires a sensor. My Yanmar manual(2QM20/3QM30) is on the boat but I have attached the basic wiring diagram from the manual. I do not know where that sensor screws in exactly but is has to be over the flywheel somewhere.
P
Pat McCartin
Greg,
The Yanmar tach sensor goes in the bell housing. near the starter. There should be a boss for it there, the boss should be drilled and tapped already. You might already have the wires in your harness also, some of the newer engines had the sensor in place and wired to the engine harness connectors.
The Yanmar tach sensor goes in the bell housing. near the starter. There should be a boss for it there, the boss should be drilled and tapped already. You might already have the wires in your harness also, some of the newer engines had the sensor in place and wired to the engine harness connectors.
P
Pat McCartin
Alternator driven tach's
Ed, You bring up a good point. It is posible to update to this type of tach. They are driven by the AC sign wave off of the alternator. Only problem is calibrating it to the engine. You need to get the real RPM with a photo tach at the crank and then set the tach to agree with the engine. This might be an inexpensive alternative. Try to rent or borow the photo tach thou, they cost about $300.00
Ed, You bring up a good point. It is posible to update to this type of tach. They are driven by the AC sign wave off of the alternator. Only problem is calibrating it to the engine. You need to get the real RPM with a photo tach at the crank and then set the tach to agree with the engine. This might be an inexpensive alternative. Try to rent or borow the photo tach thou, they cost about $300.00
P
Paul F
Might try a Tiny Tach
There is a product which feeds from the fuel line, it is called Tiny Tach. An interestng concept and it may be a good answer for an add on diesel tachometer. This product was suggested in a message last year. I don't have any experience with it, but those who have used it seem to like the ease of installation and the performance. Maybe someone who has used one could give us their experience with the Tiny Tach. I have tried to find one in marine stores but none carry it. So the only way I know to get one is by mail. Here is a link to the web-site.
There is a product which feeds from the fuel line, it is called Tiny Tach. An interestng concept and it may be a good answer for an add on diesel tachometer. This product was suggested in a message last year. I don't have any experience with it, but those who have used it seem to like the ease of installation and the performance. Maybe someone who has used one could give us their experience with the Tiny Tach. I have tried to find one in marine stores but none carry it. So the only way I know to get one is by mail. Here is a link to the web-site.
M
mike
tachometer
The tach sensor is just above the starter over the flywheel.I will post a photo when I get home tonight. There are 4 wires on the back of the tach (Ground,power,G,S). Two wires go from the tach to the sensor(G,S).
The tach sensor is just above the starter over the flywheel.I will post a photo when I get home tonight. There are 4 wires on the back of the tach (Ground,power,G,S). Two wires go from the tach to the sensor(G,S).
G
Gene Gruender
Alternator one cheaper, but....
If you use the alternator type, there is one thing you should know. When the batteries are charged and the regulator shuts off charging, the tach will quit. For a few seconds, a minute or whatever. If you have other charging sources, like wind or solar, they will can keep the voltage up high enough that the regulator will not cut in for long periods of time. During that time your tach will be off. This is not necessarily such a bad thing, but if you are unaware of it, you may spend a lot of time, and maybe money, trying to solve a non-existant problem. I have just such a setup and have found it to be quite adaquate for 6 years and 10,000 miles of cruising. The alternator driving tack is far cheaper than the Yanmar version. Shop around and you can get one for under $100, maybe under $50 (I think I paid about $40 for a discontinued model). The Yanmar one was around $300 at the time.
If you use the alternator type, there is one thing you should know. When the batteries are charged and the regulator shuts off charging, the tach will quit. For a few seconds, a minute or whatever. If you have other charging sources, like wind or solar, they will can keep the voltage up high enough that the regulator will not cut in for long periods of time. During that time your tach will be off. This is not necessarily such a bad thing, but if you are unaware of it, you may spend a lot of time, and maybe money, trying to solve a non-existant problem. I have just such a setup and have found it to be quite adaquate for 6 years and 10,000 miles of cruising. The alternator driving tack is far cheaper than the Yanmar version. Shop around and you can get one for under $100, maybe under $50 (I think I paid about $40 for a discontinued model). The Yanmar one was around $300 at the time.
- Status
- Not open for further replies.