Problem with tachometer on Mercury 1150

[Guztav123]

Hello!

I have bouht a marine tachometer to my Mercury 1150 1976 year model. But i cant get it to function. I have tried connecting it to the mercontrol and also directly to the switchboxs brown connection. The gauge has settings on the backside, wich should I use?

Best regards /Guztav

 

[Chris1956]

Re: Problem with tachometer on Mercury 1150

The tachometer is designed to run off the stator pulses. Move the brown tach wire from the switchbox to one of the stator (yellow) wires at the rectifier. The tach should be set on 12P

 

[Guztav123]

Re: Problem with tachometer on Mercury 1150

Thank you very much, I will try that! I'l come back with the resaults!

 

[Guztav123]

Re: Problem with tachometer on Mercury 1150

I didn't have a 12p setting on my tach, but I phoned the dealer that sold me the tachometer and he said that the 6p position should work fine. So I put it on 6p and changed the brown cable position to one of the yellow cables from the flywheel and the Tach started working! Great!!

But... Now It seems like I'm having problem with my batterycharging instead, The battery is on the same Voltage all the time, it dosen't get higher when the engine is running. What is the first thing to check, where can I messaure to se If the engine charges?

Sorry for bad english.

/Guztav

 

[carholme]

Re: Problem with tachometer on Mercury 1150

Gustav;

Here is a schematic to support what Chris said:

Merc Model 900-1150-1500........1976-78 Wiring Diagram

From here:

http://www.maxrules.com/MERCwireindex.html

Gerry

 

[Guztav123]

Re: Problem with tachometer on Mercury 1150

Thank you Gerry! Where do you think I can messaure to se if the engine gives any voltage?

 

[carholme]

Re: Problem with tachometer on Mercury 1150

Guztav;

Without knowing anything else about your engine problem, the easiest would be to accurately measure the battery voltage with a volt meter. A good target would be 12.5V. Then, run the engine and rev it up to about mid range and with the meter record the voltage at the battery again. If it is higher than the static battery voltage, ie; 14V. this will show that the charging system is working.

Ensure that you are using a good battery.

Use a good meter, not the gauge on the instrument panel. If you don't see that the battery is charging, then you have to start looking into other things.

Gerry

 

[Guztav123]

Re: Problem with tachometer on Mercury 1150

I have used a good proffesional meter that we have at work, and I have measured at different engines rev with the same voltage as the engine shut down. It is about 12.5 voltage whenever the engines running with high revs or when its shutdown. I have measured the ac voltage on the two yellow wires from the flywheel and it's only 10 volt. It sounds little but it has the same resistance as the other flywheel i have on the shelf. What do you think?

 

[daveswaves]

Re: Problem with tachometer on Mercury 1150

Guztav;

Without knowing anything else about your engine problem, the easiest would be to accurately measure the battery voltage with a volt meter. A good target would be 12.5V. Then, run the engine and rev it up to about mid range and with the meter record the voltage at the battery again. If it is higher than the static battery voltage, ie; 14V. this will show that the charging system is working.

Ensure that you are using a good battery.

Use a good meter, not the gauge on the instrument panel. If you don't see that the battery is charging, then you have to start looking into other things.

Gerry

Excellent answer Gerry, Gustav it would also be helpful to know what type of battery you have. For example, is it deep discharge, starting only, car battery?
It can take a lot of charge out of a battery when starting an inline and the charging system is only 9 amps. It will take a long time to replace what you took out when you started the engine.

 

[daveswaves]

Re: Problem with tachometer on Mercury 1150

I have used a good proffesional meter that we have at work, and I have measured at different engines rev with the same voltage as the engine shut down. It is about 12.5 voltage whenever the engines running with high revs or when its shutdown. I have measured the ac voltage on the two yellow wires from the flywheel and it's only 10 volt. It sounds little but it has the same resistance as the other flywheel i have on the shelf. What do you think?

Gustav, it sounds like your rectifier is kaput. Your can replace it with a full wave bridge rectifier if you do not have the original Merc style.

 

[Guztav123]

Re: Problem with tachometer on Mercury 1150

I have a car battery and yes i have tried replacing the rectifier already with the same resault. I replaced it with a used one so it is a possibility that also that one was out of order, but the salesman said that all the used stuff I bought where in order, but you could never be sure of course... Is there any way I could check if the rectifier is in order?

 

[carholme]

Re: Problem with tachometer on Mercury 1150

Guztav;

Here is a rectifier test which you can save to your computer:

http://img830.imageshack.us/img830/8328/rectifiertesting.jpg

Gerry

 

[1979checkmate]

Re: Problem with tachometer on Mercury 1150

yep do that test, if it is bad, replace the rectifier. Yes, you can use a full wave bridge rectifier from Radio Shack... if you want to stay cheap. I did that to finish out last season. This winter i replaced the entire ignition system in my motor, stator, trigger, coils, switchbox's and i just didnt feel like skimping on the rectifier. I payed 30.00 for a new CDI unit to my door.