Motor Will Not Start

[Cootz]

Hello I am a bit stressed out right now as my Johnson 9.9 will not start at all without using liquid fire it was starting first pull last week and like I said before will not start I got new spark plugs bit that has not solved the problem if someone could give a answer or idea to what's going on it would be much appreciated thanks

[Way2slow]

A motor runs on a very basic principle. A 13:1 approx fuel air ratio under compression with a hot enough spark at the proper time to ignite it.

If one of those elements are missing or off, it's not going to run, you just go through the process of elimination to figure out which one.

Now, you said it will start on liquid fire, I'm assuming you are referring to starting fluid, which is not a good thing to use in a two stroke motor because it has no oil in it for lubrication. It's much better to use a little premixed gas in a spray bottle.

With that said, if you are referring to it will run on either, then that seems to narrow it down to a fuel delivery problem.

Before I can go any further, I would need more info on the motor, is it a two stroke or four stroke, approx what year model.

[Cootz]

It's a 2 stroke Johnson 1981 for a year we may have singled out the problem as the choke keeps falling out when we put the choke back in and pull it out it shoots back in so you can't choke it

[CWB]

Think what might have changed in a week. Always check the obvious first. Plugs, connections, fresh fuel, clogged filter, etc. etc. 2 cycles ate not that complicated, especially the smaller ones. You have the advantage of taking it in your garage and have access to everything. Get a manual and start troubleshooting.

Please clarify what you said about the choke. "When we put it in it shoots back in" ?

If you like the motor, try fixing the choke, re-building the carb, or buying a new or re-built one.

[Cootz]

Thanks and to clarify it, when you pull out the choke on most engines you can push it in and out in a smooth motion but with this one there's a click that happens when pulling out that is not smooth then once I get it to full choke it just goes back as if it were off

[Way2slow]

The choke on that motor is not a smooth motion, there are notches in the choke knob a detent spring drops in to hold the knob in different positions.

If you look at the chock knob, it has a slot cut in it that sits over the choke lever on the carb so when you push and pull the choke knob, it pushes and pulls the choke lever on the carb. The choke knob has a couple of notches in it where a spring detent presses down on the choke knob and drops in those notches to hold it. I'm not sure if you can, I've never tried to see, but it sounds like you might have the choke knob upside down so the notches are on the bottom and the detent does not hit the notches. That or the detent is missing. For some reason, the detent is not holding the choke lever in the out position.

You say you can't choke it, if you spray gas in the carb, to get it running, does it keep running after that? Usually, after one warms up, it does not need the choke to start. Mine's a mid 70's and starts first 1/2 pull after I've run it

[nicksmurf111]

It's a 2 stroke Johnson 1981 for a year we may have singled out the problem as the choke keeps falling out when we put the choke back in and pull it out it shoots back in so you can't choke it

 

It probably has a choke detent ball in the carburetor.  Has it always done that?

 

Having to do with it not running; I bet you got dirt or water in the carburetor.  I'd pull the carburetor and remove the bowl.  Remove the float and needle.  If you have had any trouble with it flooding, replace the needle and seat and make sure the float isn't leaky.  If not, inspect the needle for wear.  Look for dirt in the bowl and the jet.  Either blow it out with carb cleaner, replace the bowl gasket, bowl screw gasket and mounting gasket.  Level the float.  Replace the fuel filter and any old fuel lines.

 

If the minimal doesn't work, or you think it's really clogged up, do a full rebuild...dipping it in carb cleaner per the instructions.  There are a lot of small passages.  I've worked on tons of carbs and I'm not even very competent with them, so be careful and find a professional if needed.

[nicksmurf111]

Also, dump the fuel in your lawn mower or something (use it up quickly) and start with fresh fuel.  That helps sometimes.

[Way2slow]

No, the detent is where I said it was, so don't go looking for one in the carb, it doesn't have one.

Before messing with the carb, pull the gas line off the carb, pump the primer bulb until fuel comes out of it, remove the spark plugs and loosely hold your finger over the end and pull the rope a few times to make sure the fuel pump is working. There should be about five pounds of pressure on the hose so it should make a spray if not holding down too tight. A carb can't deliver fuel if the pump is not sending it to it.

Start with the basics first. Now that you have confirmed the fuel pump,

Check for weak spark. While you have the plugs out, connect a plug wire to a plug and hold the base off it against the block so it gets a good ground, it will let you know if you don't have a good ground, holding it so you can see the electrode. Pull the rope a few times and make sure you have a good blue spark. Red usually will not run it. Do this on both plugs wires.

If you have a compression gauge, check it. Hold the butterfly in the carb open doing that, or it can cause one to show low compression.

We are pretty sure it's getting air.

Check the fuel pump like I explained, make sure the fuel pump is delivering fuel.

Make sure you are getting a good spark.

As for the timing of the spark, that's a little more complicated, but one of the main causes of it to change is a sheared key in the flywheel. So for now, we will assume it's good.

Now:

We have confirmed the fuel pump is pumping gas to the carb

We have a confirmed good spark

We have compression and going to assume the timing is good.

So, if it still won't start, you might want to look at pulling the carb and cleaning it. If you pull it off, looking inside the intake with a flashlight and make sure the reeds have all the holes plugged. Just to make sure it hasn't broken one. That's rare but it can happen.

[nicksmurf111]

No, the detent is where I said it was, so don't go looking for one in the carb, it doesn't have one.

 

Woops, sorry.  I was thinking of a different motor.  But it should run with a bad fuel pump if you squeeze the bulb to re-fill the bowl.