Yamaha Four-Wheeler Won't Start

[csprain]

I have a two-wheel drive Yamaha Timberwolf from the early 1990's. It has the 250 cc motor. I received the four wheeler from a buddy for $100. I have done the following already. Replaced oil and filter, replaced spark plug, replaced battery, replaced ignition coil, had the carb professionally rebuilt, and added fresh gas. This is the first four wheeler I have owned so forgive me if some of my questions seem obvious. The motor cranks but will not fire. I tested for power at the wire going to the coil and there was power when i grounded my test light on the battery. But when I ground it on the ground wire to the coil the test light will not illuminate. Also when connected I have no power at the end of the spark plug wire. (I hooked the ground side of the test light to the battery and the power side to the spark plug wire and got nothing). So does this mean the ground going to my coil is bad? I do not get any spark at the plug. Thanks for any help. Really anything.

 

[MH Hawker]

Re: Yamaha Four-Wheeler Won't Start

Is the kill switch on.

 

[csprain]

Re: Yamaha Four-Wheeler Won't Start

No the kill switch is off. I did not change anything between now and my previous post yesterday. But I cannot get any power to the coil at all now. Not sure what to do next?

 

[RogersJetboat454]

Re: Yamaha Four-Wheeler Won't Start

Also when connected I have no power at the end of the spark plug wire. (I hooked the ground side of the test light to the battery and the power side to the spark plug wire and got nothing). So does this mean the ground going to my coil is bad? I do not get any spark at the plug. Thanks for any help. Really anything.

Uhh...
Really sounds like you need a shop manual for your quad, and to also study up on engine fundamentals.

You are not going to see voltage at the end of the plug wire like you're testing a light socket. The coil produces up-wards of 15-20Kv (15-20,000 volts), possibly even more (my numbers are a guess). I don't know of any multimeters, or test lights designed to directly handle 20Kv. If the ignition system was working, chances are you would have blown the bulb in your test light.

I would assume that era quad has a electronic ignition. You need a shop manual and a multi-meter to properly diagnose it with out guessing and throwing parts at it.

You could also join a ATV enthusiast forum to see if there is anybody that could assist you with procedure, and common issues with your particular model.

 

[ehenry]

Re: Yamaha Four-Wheeler Won't Start

Have you put a spark plug in the plug wire and grounded the electode of the plug to the engine and spun the engine over to see if there is any fire at the plug? It should be a good blue spark. Thats the easiest way I know to check to see if its firing. If its firing, start checking fuel.

 

[bigdee]

Re: Yamaha Four-Wheeler Won't Start

Have you put a spark plug in the plug wire and grounded the electode of the plug to the engine and spun the engine over to see if there is any fire at the plug? It should be a good blue spark. Thats the easiest way I know to check to see if its firing. If its firing, start checking fuel.

Good advice and good 1st step. Go online and download a wiring diagram. If you confirm that you are getting spark and engine still won't fire MAKE sure the air-box is attached to the carburetor. These quads will not run with the air box removed. I found out the hard way,I guess it creates enough restriction in airflow to allow gas to be sucked from venturi.

 

[MTboatguy]

Re: Yamaha Four-Wheeler Won't Start

On the timberwolf, which has a similar set up as my Kodiak, check the tube between the carb and the cylinder, there is a rubber right that encircles that tube and they blow out, which causes an over lean situation.

 

[ehenry]

Re: Yamaha Four-Wheeler Won't Start

Another thing to check on a yamaha wheeler is the carburetor vent. Make sure the vent hose that runs from the carb up to the handlebar neck is clear and not stopped up. I dont know about where you live but down here the dirt-dobbers will stop those vent hoses up.

 

[Bob_VT]

Re: Yamaha Four-Wheeler Won't Start

On the timberwolf, which has a similar set up as my Kodiak, check the tube between the carb and the cylinder, there is a rubber right that encircles that tube and they blow out, which causes an over lean situation.

After reading your post and my experience with those motors..... I agree. That rubber/plastic manifold between the carb and the motor tends to crack. I would examine that very carefully

 

[avenger79]

Re: Yamaha Four-Wheeler Won't Start

Also on Yamaha's not sure about the Timberwolf though, there is a TORS system which will keep it from starting. It is on top of the carb if it has it.

another "safety" thing we had trouble with was in the throttle grip. again had someto do with the TORS. I had to have a mech show me that one. Wound up being a 30 sec fix. Not sure how to explain it but there was essentially an open in the thottle that wouldn't let the quad start.

ours was an "03 Blaster so a little newer, yours may or may not have these items

 

[csprain]

Re: Yamaha Four-Wheeler Won't Start

On the plastuc tube going from the carb to the engine I replaced the O-ring, should there be any lubricant on it and if so what type? And I'm located in WI and from what the previous owner said it was used kind of harshly. I appreciate all the help and will look into all of the things you guys mentioned tonight and let you know about the success of them. Thanks.

 

[Tim Frank]

Re: Yamaha Four-Wheeler Won't Start

If you put a plug in it as a test, that will indicate a problem if there is no spark, but will not rule one out if there is a spark.
For that you need a spark tester and the spark needs to jump a 3/8" gap, minimum.
I see no mention of a compression check. Have you verified that?

 

[RogersJetboat454]

Re: Yamaha Four-Wheeler Won't Start

On the plastuc tube going from the carb to the engine I replaced the O-ring, should there be any lubricant on it and if so what type? And I'm located in WI and from what the previous owner said it was used kind of harshly. I appreciate all the help and will look into all of the things you guys mentioned tonight and let you know about the success of them. Thanks.

If it's like my Yamaha motorcycle, I assume the O-ring is between the manifold and the head. Those are dry fitted. If it's an O-ring that seals the carb outlet to the manifold, a little engine oil to aid in re-installation of the carb should be fine.

Are you sure the manifold is plastic, and not rubber? Rubber is commonly used, but as it ages it will split allowing for a vacuum leak. Check the manifold for cracks, and replace if you find any.

 

[MTboatguy]

Re: Yamaha Four-Wheeler Won't Start

I have had to replace mine a couple of times, the last one I put on, we partially metal and partially rubber, if you get any backfires, then it blows the rubber out, I have my ATV parked right now because of that, I was moving it to park for the winter, had a backfire due to bad gas being in it and it blew the rubber out, right now it has a piece of duck tape wrapped around it, I will have to pick up a new manifold before I can ride it this summer.

 

[csprain]

Re: Yamaha Four-Wheeler Won't Start

Okay I messed with it some, started using a DMM instead of a test light. I have power to the ignition coil and there is a nice solid blue spark. As I said the carb has been professionally rebuilt. So how do I make sure there is fuel getting to the combustion chamber? Or What is the next step now that I have spark. As I said, new battery, fresh oil change, new ignition coil, fresh fuel, carb rebuilt, new fuel line from the tank to carb. What is next? Thanks for all the help thus far.

 

[Tim Frank]

Re: Yamaha Four-Wheeler Won't Start

Okay I messed with it some, started using a DMM instead of a test light. I have power to the ignition coil and there is a nice solid blue spark. As I said the carb has been professionally rebuilt. So how do I make sure there is fuel getting to the combustion chamber? Or What is the next step now that I have spark. As I said, new battery, fresh oil change, new ignition coil, fresh fuel, carb rebuilt, new fuel line from the tank to carb. What is next? Thanks for all the help thus far.

What's next?
Not sure, but why not put on 4 new tires?
It won't get it going, but if you are throwing new parts at an engine when you haven't checked (or won't) the compression, you might as well move on to the tires.

 

[MTboatguy]

Re: Yamaha Four-Wheeler Won't Start

Take the spark plug out, fog the cylinder with gas, put the plug back in and see if it will fire.

 

[csprain]

Re: Yamaha Four-Wheeler Won't Start

Sorry, what do you mean by fog? Can I just put a few drops of gas in there?

 

[MTboatguy]

Re: Yamaha Four-Wheeler Won't Start

A few drops will work fine, I have also used WD-40, but a few drops of fuel should work fine, just work quickly so it does not all evaporate. Like Tim said, checking the compression would also be a good idea, if you don't have enough compression, you are never going to get it running.

 

[csprain]

Re: Yamaha Four-Wheeler Won't Start

Yeah I know, I do plan to check compression I just don't have a compression tester and haven't bought one. I know there is some because I can feel it on the rip cord and hear it. The engine serial number is 4BD-283555. Does this help identify the year of the machine at all?