johnson charging problem

[curtisimo1981]

ok heres the thing. i just this motor today. how can i check to make sure it is charging properely? I only have about 12.6v-12.8v at an idle. not sure what it is much above idle considering my controls dont allow me to rev it up much more. in neutral i can only rev up about 700rmp. can anyone please help me with this. i wantt to take the boat out this weekend. but want to make sure it is charging first. thanks in advance for the help.

 

[reload]

Re: johnson charging problem

What is wrong with the controls? Do you mean you can not rev it up because it is not in gear? At 700 r's I would expect to see more then battey voltage at any rate. What is the model and seriel numbers, hp, something to go on?

 

[R.Johnson]

Re: johnson charging problem

These are low amp charging system's. You need an amp meter to tell what is really happening. An amp meter, in series between the red wire from the rectifier, and stater solinoid will give the answer. Don't let the leads touch ground.

 

[curtisimo1981]

Re: johnson charging problem

yes i cant rev up b/c its not in gear it only has a warm up lever. its a 1989 90hp johnson. i checked the stator and i have between 8-9 amps coming out of each yellow wire. but not really 100%on how to check the rectifier. i have two of the exact same motors. i bought both of them to use one as parts. one had an brand new power head on it and the other was all original both run great though

 

[Seasport]

Re: johnson charging problem

What sort of controls do you have on that motor? Does it have a warmup lever? You should be able to rev higher than 700 rpm's without putting it into gear. On some controls you can disengage the gear shift by pushing in a button in the centre of the throttle lever.

The easiest way to check for charging is to measure battery voltage. You should get an increase in battery voltage (to around 13V or a bit more) as you increase revs. Don't rev the motor too high or for too long in neutral else you run the risk of breaking it.

 

[curtisimo1981]

Re: johnson charging problem

well thats the problem i'm scared to put it in the water till i know its charging. it has power tilt/trim that i had to rig up a toggle swith for b.c my contols didnt have it. all it has is a warm up lever but doen;t rev up very high. not sure b/c the tach i have on my boat is broke. it hasnt worked since i bought the boat. how do i test it between the rectifier and the sylenoid. I'm an automotive tech. so i have all the stuff to do it. just new to outboards.

 

[Seasport]

Re: johnson charging problem

You have an ammeter. Follow R.Johnson's advice. Meter on DC amps.

 

[curtisimo1981]

Re: johnson charging problem

but what am i looking for. ac current or dc and what should it read.

 

[Seasport]

Re: johnson charging problem

You need to disconnect the wire from the rectifier to the solenoid and place the +ve lead of the meter on the rectifier end of the broken connetcion and the -ve terminal on the solenoid end. Make sure the meter is set to DC 10 amps (or more)

 

[curtisimo1981]

Re: johnson charging problem

that wont damage the rectifier? what should it read? and i was looking at the recifier and it looks like you have to remove the flywheel to get to the back bolts on that motor. i have another rectifier on the other motor i could try and i was going to untill i seen that it looked like you couldnt get to the back bolts.

 

[Seasport]

Re: johnson charging problem

I think you have a 9A stator on that so look for about 9A - a bit less depending on revs. A tach not working is often a sign of a failed rectifier as the tach pulses come from there. Was it also faulty with the previous motor?

 

[Seasport]

Re: johnson charging problem

You shouldn't open the circuit with the motor running that can damage the rectifier. Open it with the motor off, connect the meter and then start the motor again. You can measure the current anywhere in the charging circuit but don't disconnect the battery, connect the meter and expect to draw the starter motor current through the meter!

 

[curtisimo1981]

Re: johnson charging problem

yea it didnt work with the other motor either. that tach that is. ok i'll try that i guess and put the results on here. thanks for the help.,