Johnson 120 won't idle

[evil grady]

The motor idles with muffs but won't in water. I changed the plugs,flushed carbs and bowls,new gas 93oct,new filter. It seems to also have a leak when motor is tilted foward,not sure.<br /> I took off the VRO and mix in tank.<br /><br /> Runs fine when your off idle. Was afraid to launch in river so, I'm not sure how it acts under load.

 

[Dhadley]

Re: Johnson 120 won't idle

Welcome!<br /><br />A couple of thoughts; flushing the carbs may not have done anything. Clean them by soaking and installing new OE kits. You may find a float sticking which may be the leak when tilted.<br /><br />Make sure you have Champion plugs.<br /><br />Use the recommended 87 octane.<br /><br />Make sure the thermostats are in and working properly.<br /><br />Good luck!

 

[phatmanmike]

Re: Johnson 120 won't idle

alot o times when motors idle fine with no load , they are dropping a cylinder or not running on all cylinders. i jad a 50hp that did same thing, till it puked a rod.

 

[evil grady]

Re: Johnson 120 won't idle

Thermostats are in and work. 87! great news for the wallet! <br /><br /> I use the oe champions,<br /><br /> High idle is good but sneezes and dies when it gets closer to idle, I'll try rebuilding the carbs.<br /> Is there a difference between testing in or out of water?

 

[Dhadley]

Re: Johnson 120 won't idle

The difference is the backpressure. Out of the water there is none and the motor will naturally idle higher and easier.<br /><br />Find that sneeze while your in there. Its sucking air somewhere.<br /><br />Good luck!

 

[evil grady]

Re: Johnson 120 won't idle

thanks, I'll try checking for leaks. Do you know how easy it is to rebuild, will my manuel be good guide?

 

[Vaugnster]

Re: Johnson 120 won't idle

I have found when testing idle out of water, to use a "bucket" instead of muffs, not only is there backpressure, but with muffs, the water pressure from the hose is "pushing" the water pump. When lower unit is in a bucket, now the pump has to draw the water in.<br />Just make sure to keep the water above the water intakes!

 

[Walker]

Re: Johnson 120 won't idle

Check your recirculation valves. I had a couple of bad ones and I chased the "sneezing" for a month or more til I replaced those valves. Mine also wouldn't start in the water.

 

[evil grady]

Re: Johnson 120 won't idle

Where are the recirculation valves?<br /><br />sorry

 

[Walker]

Re: Johnson 120 won't idle

They are up behind the throttle plate. Find 2 small hoses on each side of your motor that come off the cylinders and go forward to the intake manifold. They terminate at the check valves which are screwed into the intake manifold. The valves are supposed to allow flow in one way only. They should flow from the intake toward the cylinders. The recommented way to test them is with a syringe full of rubbing alcohol. Pull the hoses from the cylinder nipples, insert tip of syringe in hose and try to push alcohol through the hose into the recirc. valve. If you can push alcohol thru then the valve is bad. There is also an inline valve in the hosing that needs to be checked. I posted a diagram a while back. Let me see if I can find it.

 

[Walker]

Re: Johnson 120 won't idle

Grady, go to this link http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=021222 <br />The circled part is not a recirc valve. The other 4 hose terminations in the diagram are valves.

 

[evil grady]

Re: Johnson 120 won't idle

I'll go look into it!<br />thanks,<br />Dave