Yamaha 4 wheeler won't start!

[RandyJ]

It's an older Yamaha 250... I can squirt starting fluid or gas in the carb, it won't hit a lick! It definitely is getting fire and has compression.... not sure which way to go. Even with bad compression it should at least back fire. Anyone know of a good site/forum that addresses ATV's and working on them?

 

[dolluper]

Re: Yamaha 4 wheeler won't start!

http://www.totallyamaha.com/
make sure your fuel tank switch is not on emerg..reserve
kill switch on or off?

 

[windy5849]

Re: Yamaha 4 wheeler won't start!

Have a look at this link to see if your model is listed for more info.

http://web.ebscohost.com/serrc/sear...5-bb01-02bbd5a1d371@sessionmgr10&vid=3&hid=19

This is the web site and has great info on lots of different machines.Atv's,outboards,lawn mowers and etc.Hope this helps.

http://search.ebscohost.com/
Log in with:
Name: marshall
Password : public
Then select the small engine reference center icon.

 

[stackz]

Re: Yamaha 4 wheeler won't start!

it wont even backfire when you hit it with starting fluid? are you actually getting it into the carb throat or just trying to spray through the filter? are the butterflies on the carb working or closed?

you may want to manually open the butterflies and squirt a little down in there and then see if it pops for you and we can go from there. also, how do you "know" its getting fire? did you pull the plug and hold it slightly off a ground to see actual spark coming from it? or did you just put a test light inline? did you actually run a compression test on the cylinder(s)?

 

[coastalcruiser]

Re: Yamaha 4 wheeler won't start!

my yamaha generator had the same problem, i went to you tube and watched some videos on cleaning carbs
in my case the little carb has a bolt on the bottom of the float bowl, it was clogged. as well as the main jet was dirty, soaked in solvent used a thin wire and got a can of wd40 with a thin tube and blasted all the crud out.
hope that helps

 

[waterinthefuel]

Re: Yamaha 4 wheeler won't start!

Check the kill switch on the handlebars. You will be able to turn it over with the switch off but of course it won't run.

I would get an in line spark checker from harbor freight: I used one today to quickly determine my weedeater had spark and it was a dirty carb.

Without knowing if it has spark you are chasing a cat in the dark.

 

[Bob_VT]

Re: Yamaha 4 wheeler won't start!

The Yamaha's are infamous for HUGE air leaks in the mount between the carb and the motor. It would not be unusual for that pice to have a crack or deteriorated

When was it last run?

When was the carb serviced?.

 

[waterinthefuel]

Re: Yamaha 4 wheeler won't start!

Is it a timberwolf? My dad has one and I recently rebuilt the carb. But it ran just didn't run good. Now it runs like a clock.

 

[RandyJ]

Re: Yamaha 4 wheeler won't start!

Sorry for not replying sooner. I've been very busy and pooter died so I'm on a friend's now.
This 4 wheeler has been sitting for 4 years. I pulled the plug and grounded it to check for spark. It's getting very good strong blue spark. When I parked it 4 or 5 years ago it was doing the same as now.
I've tried getting it to hit or start by spraying starting fluid into the throat of the carb. I've got the switches in the correct position. So, doubt there is a problem there or I shouldn't even get spark at all.
I don't remember the year but think it may be 1987

 

[MTboatguy]

Re: Yamaha 4 wheeler won't start!

I have a 95 Kodiak that had the exact same problem, the cause was a bad boot between the carb and the cylinder, I replaced it with a solid one and have not had an issue since, the bad boot was cracked and allowing to much air to get into the mixture, it would not back fire, it would not do anything, even when I used starting fluid, it would evaporate before you could hit the start button. Check that boot between the carb and the cylinder to make sure it is not gone..

Would yours happen to be a Moto 250?

 

[rbh]

Re: Yamaha 4 wheeler won't start!

OK then, either your running lean do to the air coming in through cracks in the boots, in which case use wd 40 spraying when your cranking over, "OR"
DO A COMPRESION TEST!!!!!
The rings are hooped!!!
The valves are hooped
Or the decompression valve is carboned up or stuck open?????

 

[dirtbikejockey]

Re: Yamaha 4 wheeler won't start!

you need to ajust the valves my freind, pull of the cover and check your clearances. you may even have to pull the head off and pull the valves out and give em a good clean and reseat the valves by using lapping compound, I have rebuilt several quads in my time from the ground up.

 

[RandyJ]

Re: Yamaha 4 wheeler won't start!

I think you may be right dirtbike.... I've been told in the past that this may be the problem but it didn't make sense that it wouldn't even hit a lick tho' it had been running fine. Not sure how to set the valves since I've never done it on this type motor. I know that some have plugs that unscrew to get to the rocker arms where the adjustment is. Can anyone tell me how to check or adjust the valves?
If I can get around to it I'm going to also check compression tho' I'm convinced that it is very good.

 

[windy5849]

Re: Yamaha 4 wheeler won't start!

Check this link for your model. It may have the valve adjustment procedure you need.Hope this helps.

http://web.ebscohost.com/serrc/sear...b6f1-dcad6b45a966@sessionmgr113&vid=2&hid=119

 

[dirtbikejockey]

Re: Yamaha 4 wheeler won't start!

whats the exact model bud send me a pic? you have to take off the timing cover and check it for top dead centre on the compression stroke!!! there will be 2 timing marks one on the cams top sprocket and one on the fly wheel. gear lever side!, then you have to take off the valve covers and feel each rocker arm if they are tight it means they valves need to be ajusted. becareful if it isn't done right! you will bend the valves. If you can give me what year it is and the model i might be able to help ya with what they should be set at. Got a few books on the specs!!! i could scan some pages in if ya like and send them to ya on how to do it. check out my honda trx that i rebuilt http://www.youtube.com/watch?v=L-Hfs3GM2uA

 

[RandyJ]

Re: Yamaha 4 wheeler won't start!

It's a bit late now and getting dark. I'll try to remember to get a pic in the morning. It has been a while since I messed with it seriously. Cables are rusted now. Missing the brake cable for the back brakes. I got the frame & engine on a trade and purchased the rear end and tires off of ebay a few years ago. We rode it around a while then one day it wouldn't start and just got set to the side after that. It has been outside uncovered for about 5 years now but still has fire & compression. I just need to get serious... hard to do with so many projects going on. I've got a pile of old boats & motors that I mess with and try to sell or trade from time to time.

 

[RandyJ]

Re: Yamaha 4 wheeler won't start!

Still have not had time to get around to working on it again... too much time spent on outboards. But, yes it is a Moto 250 and no, it does not have a boot between the carb & motor.