My 360 is coughing and running very rough when it's cold & I have the choke on. The spark plug has been cleaned but again is black as can be. I also noticed if I shut off the fuel while it is cold & the choke is on the engine smooths out & runs as it should.. I assume the carburetor is getting to much fuel and not enough air is this right? Do I need to install a new jet or try something else first? I am at 5000ft and ride generally around 5000ft - 10,000 ft, plus of course it's quite cold here. I have a service manual
that gives thes different elevation for different jets but am not sure wich would be best with my various elevations. Also is there just 1 jet I need replace?

 

You are probably right. Your main jet might be to big for the thin air up there. What does your service manual say to do? The main jet is the only one to replace.

 

for the altitude ranges the manual states the following

0-1700 ft #155 STD
1700 - 4700 ft #155
4700 - 7700 ft #145
7700 - 10,700 ft #135
10,700 - 14,800 ft #125

I was thinking of trying #145, or should I go to a #135?? Also will this hurt or enhance the power of the engine?
[img]i/expressions/face-icon-small-confused.gif[/img]

 

Your probably came with the 155 didnt it? Anyway, I think you should try the 145 first. In this case going down will enhance your power.

 

Yes it did come with the #155. Thanks for your help, I'll try the #145

 

I'm no carb expert by any means but I do know that idle problems are not affected by the main jet. The main jet affects the top 25% of your throttle. Your idle mixture screw is probably adjusted too rich. Try turning it IN about a 1/4 to 1/2 turn. Good luck.

Bob

 

Yeah, you are right. Starting and idleing has nothing to do with the main jet. I was under the impression all the trouble was happening while the P360 was running.

 

My biggest problem is at cold Idle. I thought there should be an idle mixture adjustment screw but do not know where it is. Is it called something else? It dosesn't say anything about that in my service manual, is that the same thing as the pilot screw? I have adjusted my idle to several different positions with no luck. I would imagine I still need to replace the main jet being the spark plug is so black, especially at the elevation I ride. Any info on that idle mixture screw (name, location) would be appreciated, thanks.

 

Hey Uinthas: The pilot screw is in fact your idle mixture adjust. I believe turning it in (CW) leans out your idle. This setting will vary from one altitude to another. Some say to adjust out (CCW)until it idles rough then turn in 1/2 a turn. I dont know what your manual says is the correct setting. For the P650 it says 2 1/2 turns out or something like that. I actually have about 3 turns out. Hope this helps.