1983 15hp johnson, problems starting

[wmeinhold]

hey all,
I have a 15hp 1983 johnson outboard
The motor runs well, but has trouble starting.
Sometimes it starts first pull, but other times it won't even turn over.
I don't think fuel is an issue, as it is definitely getting to the carb.
any Ideas as to what the problem could be ?
Thanks

 

[kbait]

Re: 1983 15hp johnson, problems starting

Bad fuel, choke not operating correctly, leaky low speed needle retainer, bad/out- of-gap plugs, dirty carb...

Welcome to iboats!

 

[OptsyEagle]

Re: 1983 15hp johnson, problems starting

Have you tried turning the throttle to full (up against the neutral stop)?

 

[jmendoza]

Re: 1983 15hp johnson, problems starting

Question: You mentioned sometimes the engine "won't even turn over" and this is true if the engine is in gear, there is a safety feature which locks the pull starter and electric starter(if so equipped) from engaging if the throttle is opened past the "start" position. For that reason, be sure you always put the engine in neutral, fully advance the throttle ( it will only go to start in neutral) and then crank the engine. Use the choke if the engine is cold, and push it in the moment the engine fires.

 

[fishimpaler]

Re: 1983 15hp johnson, problems starting

We've tried turning up the throttle, and always have it in neutral to start.
Additionally, after it starts the first time, it will run for 5 ish minutes, die , then not start for a bit, then work fine usually

 

[kbait]

Re: 1983 15hp johnson, problems starting

Check for spark when it won't start/after it stops running. If you've got good spark and plugs - check compression. All good?.. look to fuel delivery.

 

[CatfishMN]

Re: 1983 15hp johnson, problems starting

Sounds like my old 73 25HP. In my case, the carb float was out of adjustment and I believe it was flooding a cylinder. Check to make sure the carb float is parrallel with the carb body.

My .02

 

[scott hamilton]

Re: 1983 15hp johnson, problems starting

A little more info would be helpful. Was any service completed on the motor or did it just all of a sudden start doing this?

My guess is an ignition issue...but next time it does this try:

1. pumping the bulb and if that helps you know it is fuel. Spray a little gas mix in throat.
2. Make sure spark jumps 1/2 inch and is blue.
3. Do a compression test.

Report any findings here.

 

[jmendoza]

Re: 1983 15hp johnson, problems starting

Next time you start it, keep your hand on the fuel line bulb and give it some quick squeezes if it starts to slow and die. If it picks up, it is most likely the o rings in the connectors on your line from the engine to the tank. If replaceing them does not cure it, then it be sure your tank vent is open, and look for hard lines from the connector to the pump leaking, just replace the line and use new clamps. If that does not do it, your pump diaphragms are getting old and stiff and need replacement.

 

[fishimpaler]

Re: 1983 15hp johnson, problems starting

We've tried that, doesn't seem to help, also, i'm not sure how that would explain the fact that it does not start after choking out, despite pumping several (hundred) times.

 

[scott hamilton]

Re: 1983 15hp johnson, problems starting

My guess is still ignition issue. Follow these steps and report back.

1. Spray a little gas mix in throat to totally rule out gas issue
2. Make sure spark jumps 1/2 inch and is blue.
3. Do a compression test.

If you dont do these things your not troubleshooting your motor.

 

[MWG2600]

Re: 1983 15hp johnson, problems starting

"despite pumping several (hundred) times. " The primer bulb should get hard and not pump anymore when the carb float needle seals it off, if your pumping and its not getting hard all that gas is going somewhere! Or you have a leeky o-rings on the fuel fittings

 

[jmendoza]

Re: 1983 15hp johnson, problems starting

If the choke lever is in upside down, it will not fully choke the carb, not get enough fuel, and be real hard starting when cold. If it starts right up after squiting some fuel in the intake, then it's not getting enough fuel and could be the choke. As pointed out above, check the spark as well, and do a compression test if you have a gauge.

 

[wmeinhold]

Re: 1983 15hp johnson, problems starting

The motor now starts well when cold, and runs great, but after killing the motor, it will not start again.
any ideas on what the problem is?

 

[the machinist]

Re: 1983 15hp johnson, problems starting

Kind of sounds like you may be choking it to restart, hence flooding it.