1987 YFM 350 Starts on Pull, but just spins on starter, and won't start

[billyz57]

New to Quadcrazy, Has any Yamaha owners had similar issue?

1987 Yamaha YFM 350 Starts on Pull, but just spins on starter, and won't start.

[davefrombc]

"Spins on starter". Does the motor turn over on the starter or does the starter just spin without turning over the motor?

If the starter just spins without turning over the motor there is something wrong with the one way clutch between te starter motor and the motor. If the motor  turns over without starting then  look for a

faulty relay or broken wire between the relay or  other connection in the ignition circuit. Usually if it is the neutral safety switch  the starter will not spin. If the motor starts fine using the pull start you know the ignition is good.

There should be a wiring diagram in the download section of the forum to  help you trace out the circuits.

[billyz57]

DavefromBC,  Sorry I should have been more specific.  Starter engages, engine turns over, but won't start most of the time.  After I can get it started by pulling rope and it has warmed up, sometimes I can shut it off and get it to start with the starter, but most of the time it just cranks and no start.  Thanks for the Reply!!

[davefrombc]

It might be a weak spark problem on a cold engine. Cold engines require more power to turn  over and start. The extra draw on the starter leaves a little less voltage for the spark. Is the spark plug fairly new and clean, gap on specs? battery in good shape and all connections clean and tight so it can deliver full power?. Corrosion on the terminals can set up a resistance that causes voltage and current to drop under starting loads.

[billyz57]

DavefromBC:  battery brand new and @ 12.75 VDC.  I'll check all the connections and Sparkplug, though.  Thanks for the advice!!

[davefrombc]

Best I could give from a distance let te forum know when  you solve the problem  so others with a similar one can get an idea where to  look for the possible cause. Good luck.I hope I helped.

 

[robdoyle]

Hey Billy,

Assuming you've got all the battery cable and engine ground wire ends shiny clean (using wire brush or sandpaper) there's one more thing to check.

Has the starter motor ever been removed?  Do its mounting bolts look corroded?  It grounds through the frame, so make sure the metal is shiny clean where the starter touches the engine.  You could be getting a voltage drop there.

 

Edited November 19, 2020 by robdoyle
I was replying to wrong user! (Dave instead of Billyz)

[billyz57]

robdoyle,  Thanks for the reply!  Starter has been off.  I don't see any corrosion any where.  I did try to jump the old starter direct with jumper cables when it was off the quad, and it acted like it had a flat spot, e.g. ground the case and momentarily touch the POS jumper cable to the lug, and sometimes it would just spark, and some times it would spin.  So I ordered a aftermarket Chinese repop, and it arrived today.   Installed it and same condition, starter turns the engine over, but no start when cold.  OK, I'll see if it still starts on pull rope.  Nope!  The repop starter case that goes into the engine case is ~ 1/16 to 3/32 inch longer, and somehow the compression release does not release with the repop starter installed.  OK remove repop, reinstall old starter, same cold no start condition when old starter does turn engine over, Note I did get one backfire, but still no start cold.  Thankfully pull rope engages and starts engine.  I ride it up and down the driveway to warm it up, and then shut it off and try to start it on starter, and it starts 5 times in a row with no issues.  I didn't think to keep trying more times to see if it wouldn't start. I'm open to any and all suggestions??  Thanks in Advance!!

[robdoyle]

11 hours ago, billyz57 said:

I ride it up and down the driveway to warm it up, and then shut it off and try to start it on starter, and it starts 5 times in a row with no issues.

You're welcome!

Well, since it restarts so reliably, that suggests that the battery and starter connections are ok.

But the cold start issue remains.  You have to use the pull start when the engine is cold (and only with the OE starter in place), and then the starter works when the engine is warm.

You're not the only Yamaha owner with this problem.  I found these similar threads: https://www.bluetraxx.com/threads/2000-warrior-pull-starts-it-runs-starter-wont-run.81426/ and https://www.bluetraxx.com/threads/2004-yamaha-warrior-350-wont-start-with-electric-button-but-starts-with-push-pull.82708/

Basically they are also suspecting that the spark is weak and testing the stator.  If you have a voltmeter you could try those tests on your stator.

However, it might not be so bad to live with it like it is, since you are able to get it running when you want.

Let us know whatever you decide to do

[davefrombc]

You can get an in line spark tester that will tell you if you're getting spark when cranking over.

Here is one carried by Harbor Freight https://www.harborfreight.com/in-line-spark-checker-63590.html

There are several others at various price points available mail order or in store at most auto and RV parts stores.

 

[billyz57]

14 hours ago, robdoyle said:

You're welcome!

Well, since it restarts so reliably, that suggests that the battery and starter connections are ok.

But the cold start issue remains.  You have to use the pull start when the engine is cold (and only with the OE starter in place), and then the starter works when the engine is warm.

You're not the only Yamaha owner with this problem.  I found these similar threads: https://www.bluetraxx.com/threads/2000-warrior-pull-starts-it-runs-starter-wont-run.81426/ and https://www.bluetraxx.com/threads/2004-yamaha-warrior-350-wont-start-with-electric-button-but-starts-with-push-pull.82708/

Basically they are also suspecting that the spark is weak and testing the stator.  If you have a voltmeter you could try those tests on your stator.

However, it might not be so bad to live with it like it is, since you are able to get it running when you want.

Let us know whatever you decide to do

14 hours ago, robdoyle said:

You're welcome!

Well, since it restarts so reliably, that suggests that the battery and starter connections are ok.

But the cold start issue remains.  You have to use the pull start when the engine is cold (and only with the OE starter in place), and then the starter works when the engine is warm.

You're not the only Yamaha owner with this problem.  I found these similar threads: https://www.bluetraxx.com/threads/2000-warrior-pull-starts-it-runs-starter-wont-run.81426/ and https://www.bluetraxx.com/threads/2004-yamaha-warrior-350-wont-start-with-electric-button-but-starts-with-push-pull.82708/

Basically they are also suspecting that the spark is weak and testing the stator.  If you have a voltmeter you could try those tests on your stator.

However, it might not be so bad to live with it like it is, since you are able to get it running when you want.

Let us know whatever you decide to do

12 hours ago, davefrombc said:

You can get an in line spark tester that will tell you if you're getting spark when cranking over.

Here is one carried by Harbor Freight https://www.harborfreight.com/in-line-spark-checker-63590.html

There are several others at various price points available mail order or in store at most auto and RV parts stores.

 

 

[billyz57]

I'll get an in line spark tester tomorrow, and see what the Yamaha does, and let you know.  The other links that were posted talk having a bad pickup coil on the stator, and talk to how you can ohm it to verify.  Where do I test the stator at?  Again Thanks for your Help!!

[robdoyle]

Do you have the service manual pdf yet?  (You might need to have at least 10 posts to be allowed to download.  By the time you answer the question, you'll be there!) 

Anyway, the "Ignition Circuit" tests the you want are on page 7-21 to 7-26 of that manual.  You'll need a voltmeter for the resistance tests.  (I use the cheap red Harbor Freight one that everyone else uses.  Harbor Freight Item #63759 https://www.harborfreight.com/7-function-digital-multimeter-63759.html)

Sorry I can't tell you exactly what the connector looks like or where it is. My 2012 Big Bear is different and the pictures in the 1987 pdf manual are not great, but it shows a 4-wire harness (yellow/green/gray/blue) coming out of the left side of the engine case (there is a picture of the stator and CDI rotor on page 3-15), which you need to disconnect to test the resistance of each of two pickup coil windings.  You should also test the resistance of the source coil winding and the ignition coil primary and secondary windings. (the resistance values are on page 7-24 and 7-25).  Basically you should follow the whole test procedure and do ALL the tests, and record the results and see if anything is out of spec.  There may be several values that are marginal and together they reduce the system efficiency.

[billyz57]

robdoyle,  Thanks for the link!  This should be my 10th action, so I should be able to download it after sending!  Take Care!  billyz57

[billyz57]

It must be the new math, I am up to 10 on the profile content count, and I count 12 for posts or reply's.  Ajmboy what am I missing in order to get to 10?

[davefrombc]

Try the link again.

Edited November 22, 2020 by davefrombc

[gears]

Had the same thing happen with my 400, turns out the starter motor brushes were almost gone. I ordered up a rebuild kit off ebay and put a new brush assembly in the back. Starts right up now. Low brushes and gunk were making it spin too slow to fire up.