1986 Johnson 120HP - Hard start when cold

[tonyg]

I bought this motor a year ago and have always found it difficult to start when cold or after about 1 hour at anchor.<br />When running, it is doesn't miss a beat running fast or just idling. When warm it starts perfectly.<br />I've tried various techniques e.g. varying amount of choke and throttle lever.<br />When it does finally starts, sometimes it is smokey and sometimes not.<br />Is there anything simple I can try? The more complicated solutions I would sooner leave to the professionals.<br />Any suggestions will be gratefully received.

 

[JB]

Re: 1986 Johnson 120HP - Hard start when cold

Howdy, TonyG. When you shut down, do you run the carbs dry with the fuel line disconnected? The oil pump will continue to work and load up your carb with too much oil if you do this.<br /><br />More likely you are not getting complete enrichment when you choke it. Give the primer bulb a few extra squeezes while trying to start and ensure that it gets hard and stays hard. Do not advance the throttle when starting. If it wont start at idle, there is a problem.<br /><br />If that doesn't do the job, load a hand spray bottle with premix fuel and spray it into the air intake when trying to start.<br /><br />If either of the above gets her to start up quickly, overhaul the fuel pump and replace the primer bulb. Ensure that there are no air leaks in you fuel lines.<br /><br /><br />If it doesn't appear to be a fuel supply problem, check the synchronization between the throttle and the ignition stator plate.<br /><br />Let us know how that does.<br /><br />Red sky at night. . .<br />JB

 

[Dhadley]

Re: 1986 Johnson 120HP - Hard start when cold

The spark plugs, type fuel and oil have a lot to do with it. Check out the things JB mentioned and let us know what plugs, fuel and oil you are using. You may want to consider a de-carb job if you haven't done it for a while. <br /><br />If everything checks out, try this; 1) squeeze the bulb tight. 2) Turn the key to "ON" and push in the key to engage the primer. 3) Count to 8 (give or take -- you'll figure this out) 4)Turn the key to the "start" position. <br /><br />It should start without throttle advance but since it doesn't have Quick Start, you may have to advance the throttle slightly and/or bump the choke. Let us know about the plugs, fuel and oil.<br /><br />Good luck!

 

[tonyg]

Re: 1986 Johnson 120HP - Hard start when cold

Thanks JB & Dhadley, I appreciate your help.<br /><br />Here are some answers:<br />No I don't disconnect the fuel line.<br /><br />Sparkplugs are Champion QL78YC. When checking this, I pulled them out and found them to be a bit sooty and crusty. <br /><br />Oil is Yamalube 2 Stroke (This came with the boat)<br /><br />Fuel 91 octane.<br /><br />I'm not sure when I'll have the boat out next but I'll try your tips and let you know the results.<br /><br />Thanks again, you guys are legends.

 

[Dhadley]

Re: 1986 Johnson 120HP - Hard start when cold

The plugs and oil are OK. I would not use 91 octane if it were mine. It also sounds as if you dont get to use it very often. The "sooty" plugs indicate a problem. Clean the carbs and install good quality kits. If the fuel is more than 30 days old get rid of it and start with fresh 87 octane fuel. Get some Engine Tuner and decarbon the motor while your at it. Are you using the oil injection or mixing the oil in the fuel? There are a couple of other things to look at but lets start with these.<br /><br />Good luck!

 

[tonyg]

Re: 1986 Johnson 120HP - Hard start when cold

Thanks for the reply Dhadley.<br />87 Octane is not available in New Zealand, only 91 & 96.<br />I am not mixing the fuel & oil. Is the VRO unreliable?<br />The boat gets used about once every 2 weeks at the moment (Summer) and then 2 or 3 times over Winter.

 

[Dhadley]

Re: 1986 Johnson 120HP - Hard start when cold

Oops! My mistake for not noticing where you are. The fuel is fine. Lets clean the carbs and go from there. The oil injection is fine. <br /><br />Good luck!

 

[tonyg]

Re: 1986 Johnson 120HP - Hard start when cold

Thanks, I'll be in touch in about 1 week.