Idle problems

[sjr]

I have an 89 Johnson 90hp. Whenever I try to back the boat off the trailer, the engine dies when I put it in reverse. The only way I can keep it running is if I slam it into reverse. I had a tune up, carbs rebuilt, fuel lines and bulb replaced. It runs great at high speed but idles rough. It seems to help when I depress the choke as it is idleing. Also the overheat horn will go off when I first start up the enging. I had a new water pump installed at the time of the tune up and there is a steady stream of water coming out of the engine. What brand of spark plugs is best? Could and additive be added to the gas to clean out everything? The engine has sat up for several months.

 

[ahollinger]

Re: Idle problems

Sjr,<br />I have a 115 johnson that idles like a dog when you first start it up to pull off the trailer. I have found it helps to keep the engine level to the water when starting. On the ramp, if it is level with the boat, it sits at an incline and the floats in the carbs don't let enough fuel into the carbs. When I pull off the trailer, I have to trim down to get the motor level again. As long as it is close to level, it will idle ok long enough to warm up and smooth out. Is your idle rough all day, or only when cold?

 

[Dhadley]

Re: Idle problems

Have the carbs been cleaned before or after it sat up for months? How old is the fuel? What oil / plugs?<br /><br />Spider has some good advise with the angle. Some motors are more sensative than others.<br /><br />Good luck!

 

[sjr]

Re: Idle problems

Once I get the boat in the water(level) it still dies out when I put it in gear. After I run it for 30 minutes or so, it idles ok but it still wants to quit when going into gear. The carbs were rebuilt about two years ago. The engine was not used much, less than an hours running time in two years. the plugs were replaced when the carbs were worked on and again a few month ago. The oil I use is a premium oil made by Mercury and I have the problem aif I use old or new gas. Would it do any harm to set the idle faster? Thanks for trying to help.