Tweet
I have a carburated 91' 115 Yamaha. I recently changed the plugs on it. Ever since then it seems to be running a little rough. It also stalls out sometimes when it is in gear idle. It idles at around 400-500 rpms. Could it be bad plugs or just a coincidence and something totally different?Can spark plugs affect the idle of the boat? Also, how many rpm's should the engine idle at?Thank you for any help you can provide
-
-
you should be idling about 700 and new plugs shouldnt make it run worse. while running, pull and replug each plug wire at a time and listen for a change as you may have gotten a bad plug, rare but possible. more likely the other side of the motor,carbs.hows it run at other levels? -
The motor runs great at other speeds. It is only when it is just in gear that it seems to be having problems.Thank you for the quick replyComment
-
blake,
Like jb says, bump up your idle (in neutral) to about 700. Then do a shock treatment on the motor with RingFree or SeaFoam - sometimes works to clean up carbs.
If that does not help and if you can get to the low speed jets, try removing them and squirting some Berryman's Chemtool into the orifices.
Good luck [img]smile.gif[/img] ,
Ken KComment
-
What is the best formula for a seafoam shock treatment?Comment
-
blake,
This is from a previous post of mine - besides getting rid of a lot of carbon, the shock treatment will also clean the fuel system:
Two strokes build up a lot of carbon internally and need to be de-carbonized by doing a "shock treatment" with a detergent like Seafoam.
I like to do the shock treatment once a year on my C115 - in late winter when I am going thru my list of "spring make-ready".
If you use a detergent like Yamaha Ring Free or SeaFoam all the time in your fuel tank, then the carbon buildup is not as bad. Still, a lot of 2-stroke owners will de-carbonize once a year - you will get various opinions on this.
I "shock-treat" my C115 by running the following mixture thru it. This will smoke up the area pretty good, and leave a lot of carbon on the drive way:
16 oz can Seafoam
3/4 gal gas
3 oz oil (2 if oil injected)
Disconnect the fuel line at the input to the bulb and attach a three foot piece of fuel line to the bulb. Mix the above in a small container -
I use an empty 5 quart oil jug. Set the container on the deck of your boat and insert the fuel line and secure to make sure the end stays on the bottom of the container. Pump up bulb and start outboard with earmuffs and water hose, of course -run a little above idle for 15 minutes and turn off. Let sit for 15 minutes. Run again for 15 minutes. Let sit 15 minutes. Repeat until all mixture is consumed. Reattach main tank hose to bulb and run regular fuel/mixture thru motor for 10 minutes - you want to get the concentrated detergent out of the fuel system.
Now, clean up the drive way before your wife sees all that nasty carbon and makes you get rid of your boat.
Good luck [img]smile.gif[/img] ,
Ken KComment
Comment