Rough Idle

[dannyl]

'01 Tracker, 40hp, 2cy cannot get it to idle smoothe. No problem with it cranking. Sounds as though its only firing on one clinder. At top end it doesn't seem to miss a stroke and attains the max rpm. Today, I took down the carb and inspected it carefully. It looked clean as if it just came from the factory. I've changed plugs and fuel filter and it doesn't help. Could it be the reed valves? I've only had the motor one year and this is the second time I've had it running. It was obvious that the carb had never been taken apart.

 

[Mnemonic]

Re: Rough Idle

Did you verify that both cylinders are firing? Get it idling and then take off 1 spark plug boot at a time (Wear rubber gloves) and see if the motor boggs down or stalls. That means that the cylinder was firing OK, if it just keeps running on the cyl you unplug, it isnt firing... check the coil.<br /><br />But honestly it sounds like a fuel problem to me, did you make sure the needle wasnt stuck in the seat? Make sure the float is at the proper height?

 

[dannyl]

Re: Rough Idle

The float valve works fine. I removed the plug wires, one at a time and the motor keeps running each time. Matter of fact, sounds a little more smooth firing on one. I removed the plugs and note that the ends of the plugs are wet with oil. (because it doesn't evaporate) Actually, you can wipe it off with your finger. This motor has an oil resevoir and feeds the two cycle oil automatically. Could it be getting too much oil. The experience I have with two cycle engines was thirty years ago (lawn mowers, chain saws, etc.) and the oil mixture seemd to be inportant in the way they idle. Could that be a problem?

 

[Mnemonic]

Re: Rough Idle

I dont think the oil mixture unit is the problem... If it was feeding too much oil you would know it by the amount of smoke pouring out of it... <br /><br />I really think this problem lies within the carburetor. I am not familiar with what carb that has on it, but check the jets for blockages.<br /><br />If the motor runs with just one cylinder, on both cylinders, then thats good news, that means its not an electrical problem.

 

[Bob H.]

Re: Rough Idle

Fuel pump diaphram may be stretched resulting in fuel flow problems at low rpms. Simple fix and cheap (about $2). After that, I would check compression. If it's ok - split, clean, and adjust the carbs.

 

[Moody Blue]

Re: Rough Idle

First thing I would check is the idle mixture setting. Doesn't sound like its set up properly.<br /><br />With the engine off *lightly* turn the mixture screw all the way in. Now turn it out 1 1/2 turns. This is a starting point. Start the motor and let it warm up (on muffs or in a barrel etc). Slowly turn the mixture screw OUT (richer)until the motor runs rough and note the position of the screw. Now turn the screw IN (leaner) until the motor begins to speed up then misfire and note the position of the screw. Now set the screw midway between the two noted positions. Adjust it a "little" on the rich side if anything.

 

[dannyl]

Re: Rough Idle

Thanks for the info Rodc but I have done that. Matter of fact runs better at 1 1/2 turns off seat than any other position. I adjusted it outward less than 1/8 turn at at time until it stalls and inward the same way until it stalls and 1 1/2 turns off seat is where it runs best but still misses and vibrates likes crazy.

 

[Moody Blue]

Re: Rough Idle

While on the lake, if you hammer the throttle from idle is there any hesitation, sputtering etc., or do the RPM's increase quickly and smoothly ?

 

[dannyl]

Re: Rough Idle

On the river, I throw full throttle and it gets out. No sputtering or hesitation. At full throttle it doesn't seem to miss a stroke.

 

[dannyl]

Re: Rough Idle

Out in the bay, I can run it full throttle for thirty minutes continuous and its as smoothe as a sewing machine. No skip, no miss or aything.

 

[dannyl]

Re: Rough Idle

When I had the carb apart, I ran a piece of mono fishing line through all of the orfices and blew them out with an aircompressor. I was so clean that I didn't believed them be be plugged however I did that to make sure.

 

[dannyl]

Re: Rough Idle

I don't have a gauge to set the float level in the carb but visually looking at it, seems to be about the correct level.

 

[dannyl]

Re: Rough Idle

Haven't had a chance to check the fuel pump diaphram as someone suggested earlier.