Johnson 5HP 2003

[akis-yamaha]

Hi guys

I have an old (2003) Johnson outboard to use very sparingly on emergencies only,

Currently it is not starting at all, not even a small hiccup or "cough". I am not sure if there is spark, and I do not know how to check for it while cranking. There is plenty fuel and the fuel pump was leaking, I fixed it and is now pumping very well.

Is there an easy way to check for spark while cranking?

I can have someone in the water to look at the back of the engine where the spark plug is while I crank it but the spark plug needs to be in contact with the chassis which I think is hard to do. And maybe we will not see it under the strong sun?

Any advice appreciated!

[robert graham]

Spray a little gas/oil mix into intake and give her a pull to see if she'll try to start....if it tries to start then you'll know it's probably a fuel issue.....

[TownsendsFJR1300]

Hi guys

I have an old (2003) Johnson outboard to use very sparingly on emergencies only,

Currently it is not starting at all, not even a small hiccup or "cough". I am not sure if there is spark, and I do not know how to check for it while cranking. There is plenty fuel and the fuel pump was leaking, I fixed it and is now pumping very well.

Is there an easy way to check for spark while cranking?

Pull the plugs, insert one at a time in the spark plug wire, ground plug to the block(clean metal). Have your buddy turn the starter key to crank and look for spark.

If it's too bright outside, hold a piece of cardboard (or similar) over the area. You should see it.

Turning the engine to one side or the other should allow "no one to get wet"...


Looks like it's a simple magneto / coil set up: https://www.boats.net/catalog/johnso...r4sts/ignition

Should you have no spark, there should be a separate small wire for the kill switch attached to the coil-disconnect it and try again (by-passing the kill switch). If you still have no spark, your coil is likely toast. (not unusual)...

[walleye1]

Test for compression, spark and fuel. Are you lost?

[99yam40]

why post about a non Yamaha on a Yamaha forum?

oh yea, pull the plug wire off the plug and stick a screw driver up in the plug wire,
grab the metal shaft of the screw driver in one hand and then touch the back of that hand to the metal of the motor.
when someone pulls the start rope you will feel a shock if it is putting out any voltage

or you can get a spark tester or the proper test equipment to measure voltage output

[akis-yamaha]

Hi guys

The main engine is an old Yamaha F80 and I found this forums sometime ago when diagnosing the F80.

I tested the kill switch, with the key in it shows large impedance (like 3-4MOhm) and with the key out it shorts the two wires.

There is no starter motor and the engine needs to be cranked by hand. While cranking it shakes quite a bit and the boat is in the water but I will try to look for spark somehow.

Thanks

[zenoahphobic]

You probably won't get much of an answer on the Johnson forum. Go with the above.
If you have someone standing in the water holding the plug and he dose not jump when you crank, you probably have a faulty ignition system!😳

[rodbolt17]

why not google "homemade spark tester" ?
I posted it years ago.
the kill circuit operates by grounding the black/yellow wire going to the CDI unit.

[TownsendsFJR1300]

With the spark plugs removed, it'd be easy to spin over by hand..

[akis-yamaha]

Hi again

It was impossible to see a spark under the strong sun. After further inspection and troubleshooting we discovered the carburetor was clogged with old fuel. After cleaning it the engine started.

The next immediate problem appears to be that instead of a trickle coming out the telltale water nozzle, I am getting a small flood with water also backing into the engine cover. I removed the nozzle cap and I can see a large amount of water coming out and I suspect that there is some blockage inside and the water does not circulate freely through the block.

I suspect it is the thermostat and have no idea how hard it might be to remove and inspect.

Will try to access it today.

[99yam40]

water should not be leaking out under the cowling.
you have a hole from corrosion or a broken hose or other part

[TownsendsFJR1300]

Hi again

It was impossible to see a spark under the strong sun. After further inspection and troubleshooting we discovered the carburetor was clogged with old fuel. After cleaning it the engine started.

The next immediate problem appears to be that instead of a trickle coming out the telltale water nozzle, I am getting a small flood with water also backing into the engine cover. I removed the nozzle cap and I can see a large amount of water coming out and I suspect that there is some blockage inside and the water does not circulate freely through the block.

I suspect it is the thermostat and have no idea how hard it might be to remove and inspect.

Part #17 is the thermostat: https://www.boats.net/catalog/johnso.../cylinder-head .

**Click on that link, then you can click on OTHER PARTS including the water pump, etc..
The parts list is a wealth of knowledge and pretty much shows where EVERYTHING IS. Don't be afraid to look...

Agreed with Yam99, either corrosion, or a split water hose is likely your water leak..

The little bit of tell tale water indicates a possible obstruction, crap, torn off water pump impellor vanes, etc.


Simply start the engine with the cowl off and look for where the water is coming from..