1994 Yamaha Kodiak Cools Off, Cranks but Won't Start?

[ThomTwo]

•••• My ATV: '94 Yamaha Kodiak 400 - YFM400FWF ••••

I know you've heard this before, but as you can see by the list below,

I've tried all the Normal stuff.

If the engine sits for any period of time and cools below 80 degrees, it won't start.

I've checked all of the following, but the it still won't start when cool. The spark plug gets saturated with gas after cranking - choke or no choke.

No fuel runs out of overflow.

1. Got good spark (OK) - NGK IRIDIUM DR8EIX - gap 0.28
   
2. Carb rebuilt (OK)
   
3. Rechecked float pin and seat (OK)
   
4. Pilot Jet set 2 turns out (OK)
   
5. Removed and Checked Choke O-ring (OK)
   
6. Adjusted intake and exhaust valves reset to spec. (OK)
   
7. battery charged (OK)
   
8. Checked, Cleaned and applied Dielectric grease to All Wiring Connections.
   
9. Got good compression 118 psi cold engine. - 152 psi Warm
   

After I warmed the head with a blowing propane heater and it did finally start and would start easily when the engine was warm.

What else is there to check?

Saturday 10/15/2011, it was unseasonably warm (80 degrees) The Kodiak started right up.

••• Still guessing

[hangingon]

let us know what you find out. I have no clue!

[swampcat07]

I would change the sparkplug if you didn't. Probally a long show but who knows.

I know somtimes when you pull it out to check the spark it will but then when it is undercompression in the chamber it won't. (Bad Plug) It happened a few times to friends and is always a easy try if you have one lying around.

A cold engine is harder to turn over. The only other option I can think of is that the timing is slightly off.

It is hard to say because it starts right up when warm. I am just guessing something with the spark because it looks like you have enough fuel.

[ThomTwo]

I swapped out three different new plugs- still no start - same good spark from each.

I notice choke seal part (Seal) #34 was missing.

Could this be the problem?

Heres the Carb Parts Diagram

[ThomTwo]

Well, installed the missing choke seal - no help.

It still won't start when the engine is cool to the touch.

I fired up the propane heater, let it blow on the engine for thirty minutes and…

… it started like a champ.

I checked the spark again and got the fire shocked out of me… Good Spark.

I talked to the dealer again… they don't have a clue either.

Still hunting for the solution… stay tuned.

[hangingon]

Do you know if the choke is closing enough?

[swampcat07]

Thats crazy. I will keep thinking let me know what you find.

[ThomTwo]

@hangingon - Yep, checked the choke first thing.

I dont think it would idle so smooth when it DOES start if the choke wasnt closing.

@Swampcat07 - Off to the dealer AGAIN today. Wondering what he will test that I havent already done.

BTW: Anyone know why an apostrophe doesnt show up when I type???

[ThomTwo]

The Kodiak went to the dealer today. The mechanic did a complete inspection of the carb.

Nothing much was wrong, but he didn't like the brass aftermarket main jet needle. He changed it back to the stock needle. He said most aftermarket needle sets were in spec.

He also changed the O-Ring on the Fuel/Air needle.

When I left he got it started after a lot of cranking and fooling with the intake.

It idles smooth just like it did when I would start it by heating up the head and spark plug.

He wanted to keep it over night and check some other things in the morning after it was completely cool.

Stay tune to the continuing saga.

BTW: The stator checked out as Good.

[swampcat07]

Sounds like you are getting closer.

Not all jets sizes are the same here is a conversion chart that I saved from another forum.

Width------Keihin # -- DynoJet # -- Mikuni #

0.0350---- 92.5--------- 92----------- 86.3

0.0360---- 95----------- 94----------- 88.1

0.0370---- 97.5--------- 96----------- 90.0

0.0380---- 100---------- 98----------- 91.9

0.0390---- 102.5------- 100---------- 93.8

0.0400---- 105--------- 102---------- 95.6

0.0410---- 107.5------- 104---------- 97.5

0.0420---- 110--------- 106---------- 99.4

0.0430---- 112.5------- 108--------- 101.3

0.0440---- 115--------- 110--------- 103.1

0.0450---- 117.5------- 112--------- 105.0

0.0460---- 120--------- 114--------- 106.9

0.0470---- 122.5------- 116--------- 108.8

0.0480---- 125--------- 118--------- 110.6

0.0490---- 127.5------- 120--------- 112.5

0.0500---- 130--------- 122--------- 114.4

0.0510---- 132.5------- 124--------- 116.3

0.0520---- 135--------- 126--------- 118.1

0.0530---- 137.5------- 128--------- 120.0

0.0540---- 140--------- 130--------- 121.9

0.0550---- 142.5------- 132--------- 123.8

0.0560---- 145--------- 134--------- 125.6

0.0570---- 147.5------- 136--------- 127.5

0.0580---- 150--------- 138--------- 129.4

0.0590---- 152.5------- 140--------- 131.3

0.0600---- 155--------- 142--------- 133.1

0.0610---- 157.5------- 144--------- 135.0

0.0620---- 160--------- 146--------- 136.9

0.0630---- 162.5------- 148--------- 138.8

0.0640---- 165--------- 150--------- 140.6

0.0650---- 167.5------- 152--------- 142.5

0.0660---- 170--------- 154--------- 144.4

0.0670---- 172.5------- 156--------- 146.3

0.0680---- 175--------- 158--------- 148.1

0.0690---- 177.5------- 160--------- 150.0

0.0700---- 180--------- 162--------- 151.9

0.0710---- 182.5------- 164--------- 153.8

0.0720---- 185--------- 166--------- 155.6

0.0730---- 187.5------- 168--------- 157.5

0.0740---- 190--------- 170--------- 159.4

0.0750---- 192.5------- 172--------- 161.3

0.0760---- 195--------- 174--------- 163.1

0.0770---- 197.5------- 176--------- 165.0

0.0780---- 200--------- 178--------- 166.9

0.0790---- 202.5------- 180--------- 168.8

0.0800---- 205--------- 182--------- 170.6

0.0810---- 207.5------- 184--------- 172.5

0.0820---- 210--------- 186--------- 174.4

0.0830---- 212.5------- 188--------- 176.3

0.0840---- 215--------- 190--------- 178.1

0.0850---- 217.5------- 192--------- 180.0

0.0860---- 220--------- 194--------- 181.9

0.0870---- 222.5------- 196--------- 183.7

0.0880---- 225--------- 198--------- 185.6

0.0890---- 227.5------- 200--------- 187.5

[hangingon]

I hope they get fixed. Do you know if they have seen this problem before?

[ThomTwo]

I left the Kodiak at the Dealer Thursday, 20 Oct.

They are still trying to figure out why it starts and runs like a champ when warm, but wont try to start when the engine is the least bit cool.

As of Saturday 22 Oct, No solution. After again testing most everything I had already tested,

The Dealer has no clue whats wrong.

Dealer closed on Monday, so I wont know any more until Tuesday.

Stay Tuned...

[ThomTwo]

Reference Post: Kodiak Cools Off - Cranks but Won"t Start?

The '94 Kodiak has been at the dealer for 3 days with no results, except for the dealer charging me $200 to check the things I told him I had already checked.

They don't have a clue. The latest from the dealer is "You probably need a TOP END at $400". I know it's 15 years old, but it only has only 900 easy miles on it.

The compression is pretty high when it's warmed up. (170 psi) spec is 140 psi.

When engine is cool the compression reads 115 psi, well within specs.

I'm going to pull the head and check for carbon build up, but I still don't understand how it starts and idles like a champ when it's warm.

Any ideas that will save me $400 will be HIGHLY APPRECIATED.

[Ajmboy]

I think the choke operation is messed up.

* Moved Post to existing thread. Added year and manufacturer to thread title.

[ThomTwo]

I didn't have the tools for the leak down test.

so I ask the dealer if they did a leak down test.

ANSWER: NO...uh..but we should have.

This is the only Yamaha Dealer within 80 miles, so I'm stuck.

Stay tuned...

[marioweldinginc]

Any possibility of a weak spark?

Sent from my SGH-T959V using Tapatalk

[hangingon]

have you tried pulling the air filter off and not use the choke to start it but put your hand over the carb. choke it with your hand too see if it will start

[ThomTwo]

I'm pulling the head and checking rings and cylinder walls.

This is the only thing on the Kodiak that hasn't been checked.

I believe i've got a bad ring or cylinder wall letting small amounts of oil into the combustion chamber.

The Kodiak only starts when warm.

[hangingon]

Hope you find out whats going on. Lets us know.

[swampcat07]

If you were flooding it with oil wouln't the plug be fouled?

Let us know what you find.

[ThomTwo]

After tearing down the head the following was found.

1) Heavy carbon build up of head and piston.

2) Cylinder worn on one side (Egg Shaped)

SOLUTION:

Bore cylinder and get oversized piston and rings.

The engine would start when warm due to the expansion allowing for correct compression and no leakage.

CAUSE: The 1994 Kodiak is 17 Years Old with No Top End ever done.

[marioweldinginc]

I would of never have guessed that one. Whats going to happen from here?

[ThomTwo]

I gave the dealer the OK to do the work.

Cost $400.

They have checked everything else from wiring to carb and the Kodiak is in great shape otherwise.

• Valves Good.

• Timing Chain Good.

• Cam and Crank Good.

• Transmission Good.

I am gonna need to replace some rubber boots.

I can replace a lot of stuff for less than $7000+ for a new machine.

[hangingon]

Glad you got it sloved. $400 is better than around $7000. A new quad would be nice but at 7000 I would get a couple good used quads and still have money left over.

[swampcat07]

That is crazy! Glad you found the problem and I learned something new.

[ThomTwo]

The dealer just finished doing the last thing he thought was why the '94 Kodiak wouldn't start until the head was warmed up to 80 degrees.

A complete TOP END was done, cylinder bored, new piston and rings.

Still won't start when engine is cool to the touch.

THINGS DONE IN THE PAST.

1. Carb rebuilt (Twice)
   
2. Compression Checked
   
3. CDI Tested Good
   
4. All Relays tested Good
   
5. All wiring Ohm to Spec.
   
6. All wiring connection checked and dielectric grease added.
   
7. Stator and Pulse Coil tested
   
8. Three different Spark Plugs tried
   
9. Spark Good
   
10. Valves adjusted, Seats cleaned.
    
11. Ignition Coil Replaced
    

I called YAMAHA Tech in California this morning, they have no clue what's causing the problem. They said have the Service Manager contact the Local Yamaha Rep.

The Saga Continues… Stay tuned.

[ThomTwo]

The saga continues with my 94 Kodiak not starting when engine is cool to the touch, but will start and run great after warming the engine head to 80 degrees or above with a heat gun.

If you've been following my posts you know what has been checked and rechecked.

All of the following have been done by the dealer:

1. Carb rebuilt
   
2. Compression Good
   
3. Leak Down check performed
   
4. Ignition Coil checked
   
5. All wiring ohm to spec
   
6. Valves checked and adjusted
   
7. Top End preformed
   
8. Starter checked
   
9. Voltage to Starter checked
   
10. Pickup Coil ohm to spec
    
11. Source Coil ohm to spec
    
12. Spark Voltage to spec
    

It still won't start until engine is warmed. It does start with the pull rope.

I call Rickey Stator today and talked to Mike. He said to check the AC voltage from the Source Coil by using a volt meter set to AC by attaching it to the Source Coil wires (Brown and Green) and cranking the starter. He said it should read between 70 and 100 AC Volts.

I picked up the Kodiak from the dealer and Ill be trying the AC Voltage Test in the morning.

Ill also be contacting Yamaha Customer Service in California explaining how much I have paid one of their authorized dealers and that I"m no better off than when I bought the ATV in.

Oh, but I do have a new Top End that I didn't need. --- Stay tuned.

[Ajmboy]

ThomTwo, I have merged your 4 threads on this same subject into this one original thread. Please do not start a new thread for updates on this topic, just update this thread. Thanks!

[seanimo]

So did you figure out what the problem was?