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Doug
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9 Posts
Discussion Starter · #1 ·
You folks rock!!! Here's my situation:

Bought 2006 Mule 610 290 hours at farm equipment auction for K$4.5 + 7% in an Indiana blizzard---ran it but limited opportunity to drive or get to speed

Starts fine
Idles okay but stalls sometimes
No acceleration w/o babying throttle and/or choke & then still very bad
Choke opens/closes freely
Babying choke does not prevent stalling while in motion
Brakes release fine
Rolls fine in neutral
If gets to speed it sputters and/or backfires
Sometimes will seem to run better for ten feet & then sputters or backfire thru exhaust annoying neighborhood dogs
Sounds like it is not getting gas
No real power
Barely moves in 4x w/o dying
During idling distinct lag/hesitation before revving
While running seems to have excessive blowback thru oil fill when cap removed---don't know if typical

Good news: No smoke ever




Done so far:
1.5 cans Seafoam in full gas tank--- existing gas
Hooked up alternative gas tank w/ new gas ---no change (NC)
New plug---NC
New plug carbons up, but not severely, after running
Cleaned carb & jets x 3 --- NC
Float and valve look fine
Plenty gas from fuel pump
Compression checks out okay Around 6.5 kg per ml squared (I think that's the correct units)
Spark tester seems to miss when it skips a beat while idling or revving in neutral---don't know if it's chicken or egg---miss firing causing spark hiccup or lack of spark causing engine hiccup
Strong spark
New oil (end of dipstick broken off where indicator line would be but filled oil to spec)
Adjusted valve clearance to spec NC
Did not yet replace gas filter but lots of gas leaving pump
Pulled air filter and no difference in problems
Never any crud in carb bowl

Read somewhere that Kawa agreed to really lean out this engine to meet EPA standards & that could cause rough idling and sputtering when cold. My situation is same whether warm or cold---maybe a little worse when warm. Currently has 1.2 R main jet & I thought of replacing it larger or smaller to see if it makes a difference. Jets are cheap. Also read somewhere to ream jet w/ welding tip cleaner to enlarge ever so slightly. Have not tried it.

Did NOT soak carb in cleaner since reading cautions re: danger of dissolving internal un-removable plastic parts

Many phone calls and hours of consultations from many years of experience to no avail. Cannot do the dealer thing for $ considerations. Much frustration on my part as well as my friends...

Mule could have taken a drink since there's fine silty sand on top of engine---I just don't know



BTW--I do have the repair manual but have tried all the probable causes

Suspect someone had had carb off before since there were scrape marks in bottom of bowl---when we looked carb was shiny clean on inside, dirty on outside

Manual shows gaskets on both sides of carb and spacer block but they were not all in evidence. I got excited. Used Formagasket but no change, drat!

Considering new jets as above
Carb rebuild?
New carb --- see $ consideration
Pulling head and lapping valves---seems excessive and no experience in doing same

Cannot work on it for a couple days since it's at a friends house

Thanx for any ideas since my brain is fried & frustrated
 

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Since you used an alternative gasoline tank, I would presume you also used new gas in your testing so that old gasoline is not the issue. Old gasoline will do exactly what you describe as your symptoms and all the SeaFoam in the world will not restore bad gas.

My recommendation at this juncture is to pull the ignition coil and have it checked. It is located down on the flywheel, and is actually a magneto impulse coil.

The 610's get dunked for an extended period, or while hot, that coil sometimes ends up shorted and no longer able to fully excite. The spark will look good but not hold up under compression.

When you removed what Kawasaki calls the needle jet, which is actually the pilot air control, from under the blind plug on the side of the carburetor, was that passage open? If the pilot circuit is plugged they will barely run. If that circuit plugs you will never get enough SeaFoam through the fuel to clean it, so it becomes a manual cleaning effort.

Once you remove the float bowl, the main jet and the pilot air screw you can clean the body and passages with non-foaming carburetor cleaner that has the needle attachment on the can without worry of melting any plastic.

You may also need to check the float level if someone had the carburetor open and tweaked that without realizing what they were doing.

These carburetors are so simple that as long as the internal passages are open and the float valve is not leaking and causing flooding they work. If the float valve is flooding, you can check it with a gravity fed fuel supply above the carburetor level with the air intake off, and look for fuel leaks at the carburetor with the engine shut off.
 

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Doug
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9 Posts
Discussion Starter · #3 ·
Since you used an alternative gasoline tank, I would presume you also used new gas in your testing so that old gasoline is not the issue. Old gasoline will do exactly what you describe as your symptoms and all the SeaFoam in the world will not restore bad gas.

My recommendation at this juncture is to pull the ignition coil and have it checked. It is located down on the flywheel, and is actually a magneto impulse coil.

The 610's get dunked for an extended period, or while hot, that coil sometimes ends up shorted and no longer able to fully excite. The spark will look good but not hold up under compression.

When you removed what Kawasaki calls the needle jet, which is actually the pilot air control, from under the blind plug on the side of the carburetor, was that passage open? If the pilot circuit is plugged they will barely run. If that circuit plugs you will never get enough SeaFoam through the fuel to clean it, so it becomes a manual cleaning effort.

Once you remove the float bowl, the main jet and the pilot air screw you can clean the body and passages with non-foaming carburetor cleaner that has the needle attachment on the can without worry of melting any plastic.

You may also need to check the float level if someone had the carburetor open and tweaked that without realizing what they were doing.

These carburetors are so simple that as long as the internal passages are open and the float valve is not leaking and causing flooding they work. If the float valve is flooding, you can check it with a gravity fed fuel supply above the carburetor level with the air intake off, and look for fuel leaks at the carburetor with the engine shut off.
The "blind plug" you mention covering the needle valve---is that the one you drill & pry out mentioned in the manual? We did not do that for fear of the unknown!

Also, you say to "have the coil tested"---who/where can do same?

As others have said, "I'm handy w/ a wrench" but new to the area of A/UTV's ---am trying to get some dependable toys for my teenage boys to play w/ me before I lose them to age-related pursuits.

Bought a Yamaha '01 Big Bear for $450 & it's now running. The Mule
should round out the toy arsenal.

Thanx so much for your assistance!
 

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That is the plug that you describe. Just use a very small bit and tape it back about 1/16th of an inch from the tip. Drill in the center of that plug until you just break through then back it out. The tape will keep you from going too deep. Then use a pick to pop the plug out, or screw in a small metal screw and use a pair of pliers to pull the plug. It does not need the plug after you finish cleaning.

Any Kawasaki dealer can test the coil. Just remove it and take it to the parts counter and ask them to test it for you. If it is bad, buy the new one from them.

Good luck on getting anyone to ride the Big Bear once they try the Mule in any really tough going! My kids dumped all the ATV's once they discovered the Mules would go anywhere and nobody ever got hurt anymore! But, we have some significant mountains in which to ride.
 

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Doug
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9 Posts
Discussion Starter · #5 ·
Hurrah!!!! Wanted to post solution found after ~50 man-hours, much assistance and hair pulling------
Re-cap---'06 610 Mule rough running, backfiring, sputtering and NOOO power

After pulling carb 20 times & cleaning (each time a little deeper), new gaskets, new plug, filters, gas, adjusting valve clearance...ordered a new coil even tho they rarely if ever go out... pulled cover to install and found the old coil had, indeed, been wet as RCW suggested, BUT also found the output wire going to the plug had been misaligned and abraded about 1/3 of the way thru---apparently by the plastic fins on the cooling fan. The plug would get spark and tested fine at idle but could not adequately supply spark needed for power. Incidentally the new Kowa coil now has an additional protective sleeve around the coil wire.

Thanks ever so much to RCW and all the wonderful forum contributors. Hopefully this is my last prob for awhile---my hair is getting too thin to pull any more out!!!
 

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Doug
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9 Posts
Discussion Starter · #6 ·
Hurrah!!!! Wanted to post solution found after ~50 man-hours, much assistance and hair pulling------
Re-cap---'06 610 Mule rough running, backfiring, sputtering and NOOO power

After pulling carb 20 times & cleaning (each time a little deeper), new gaskets, new plug, filters, gas, adjusting valve clearance...ordered a new coil even tho they rarely if ever go out... pulled cover to install and found the old coil had, indeed, been wet as RCW suggested, BUT also found the output wire going to the plug had been misaligned and abraded about 1/3 of the way thru---apparently by the plastic fins on the cooling fan. The plug would get spark and tested fine at idle but could not adequately supply spark needed for power. Incidentally the new Kowa coil now has an additional protective sleeve around the coil wire.

Thanks ever so much to RCW and all the wonderful forum contributors. Hopefully this is my last prob for awhile---my hair is getting too thin to pull any more out!!!
 

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it sounds like you have two problems #1 your air jet sounds like its to small go up 2 sizes and take a five min ride you should see a big differents in power. #2 it sounds like your coil has an internal failier that rares its ugly head speraticly. moisture was most likely the culprit for the coil failure at one point. good luck
 

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it sounds like you have two problems #1 your air jet sounds like its to small go up 2 sizes and take a five min ride you should see a big differents in power. #2 it sounds like your coil has an internal failier that rares its ugly head speraticly. moisture was most likely the culprit for the coil failure at one point. good luck
Air jet!? which one you referring to? this may help my Hesitation at start out..
 
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