Spark + fuel + compression SHOULD be enough...

C

chadincolo

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Joined
Feb 14, 2008
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5
Age
48
Location
Keenesburg CO
I'm trying to get my son's Phazer (86) finished up to take to the mountains this weekend, had to replace the stator...get the stator, put it and flywheel in, put engine in, put pipes on...check and spark plugs are sparking good on the head. Prime with a little gas, nothing. Pull plugs and check for spark, good. Prime with a little carb cleaner, nothing. Ok, maybe weak coil, change coil, check spark, good, bright arc (new plugs). Prime with carb cleaner, nothing. Pull plugs, pull engine over to blow out cylinders, put plugs in nothing. Not making any sense why no reaction, no pop, no bang, no run...try a bit of starting fluid (hate doing that, too much potential for a big bang). Nothing... I have compression. I have spark when the plugs are out (can't really see into cylinder with plugs in, but assume they spark inside). I have fuel, be it gas, carb cleaner or either...not a pop, bang, backfire...what the heck is going on? Any ideas?
 
Boy thats a dandy one huh??? lol


how did it run before the stator problem?,why did you replace it? no spark
weak spark??
 
daman said:
Boy thats a dandy one huh??? lol


how did it run before the stator problem?,why did you replace it? no spark
weak spark??
Click to expand...

Bought it with stator problems. Headlight flickering...then broken pull rope...so I never heard it run, just tore into it...longer track and skid set-back in addition to engine work. Replaced the stator with one I had (off a wrecked sled) and it didn't make spark, found a bad source coil...put this one in, good spark but ??? Someone I talked to thought that Yamaha changed the stator/CDI at some point during the run...
 
Did you set the timing?
Have you checked compression with a gauge?
 
I say timing. I assume it uses a key?!?! That's 2 cly right? You got the wires on the right plugs? Try switching them. Could be 180* off.
 
YamerDown said:
I say timing. I assume it uses a key?!?! That's 2 cly right? You got the wires on the right plugs? Try switching them. Could be 180* off.
Click to expand...

Even if the timing was off as much as possible (about 15 degrees is what the slot looks like) it would at least belch, backfire, something when using either...switching wires won't do anything, single coil, fires both spark plugs at the same time...
 
Yah, I'm not that familar with that sled so I thought I'd throw the idea out there for ya. I know what your saying, I didn't know if was a single coil or a twin coil.

What was your compression at?
 
take off the pipe, see if theres a mouse nest in it, you should be able to blow thruit very easily. Also would check the airbox.
Then if thats clear, with the pipe off, the key off and the spark plugs out, pull the rope as many times as you can before you get tired, is there alot of gas coming out of the exh port? how about if you put the piston at BDC and use the air compressor to blow air in the engine?

whats the compression guage say after you pull it over? it needs a good 100lbs per cylinder to run, if its under 90lbs it will be very lazy to start.
 
chadincolo said:
Even if the timing was off as much as possible (about 15 degrees is what the slot looks like) it would at least belch, backfire, something when using either...switching wires won't do anything, single coil, fires both spark plugs at the same time...
Click to expand...

Yes, normally it would still do something if the timing was off - but it has to be set anyway-
Low compression on both cylinders could make it not start and it may not give any signs of life. Look in the cylinders with an inspection light or remove the Y pipe and look at the pistons. Or leaking head gaskets or base gaskets.

Put one of the pistons on top dead center and put a mark on the outer diameter of the clutch right on top. Use a timing light and check it when someone pulls it over. That will tell you if you are at least in the ballpark and not way off on timing for some reason. The flywheel end of the crank could have twisted out of position.
Check to make sure the CDI box wires are matched correctly.
Try a different CDI box.
If it looks the same as the original stator, it should work the same.
There is no telling what the previous owner may have done as far as switching parts - like an incorrect flywheel or stator or CDI box.
 
It has around 120 pounds compression, so that's not the issue. No blockage in the pipes or airbox. I spent about 15 minutes burning fumes out of the cylinders...starting to think that maybe the bottom end is full of gas...I'll get a timing light and check the timing, make sure it isn't off...I doublechecked the wiring, it's hooked up right. Thanks for the ideas so far.
 
If the bottom end is full of gas, it will shoot out of the spark plug holes when the engine is cranked. Make sure the ignition is off if you do this.
 
Problem solved. Too much rotten gas in the bottom end (was flooded out) and fuel system. I had drained the tank, but not the carbs or pump. Got all the gas out of the bottom end (thanks for pulling so much Jim), fresh gas through the system, fires right up.

Will be starting it when it's cold for my son though...holy cow can does that thing pull over hard... Need to pull and clean carbs, verify timing is correct, and good to go!

Love the sound of the twin pipes, will be able to tell where he is when the thing is running... :)
 
maybe we should change the idea of fuel+ spark plus compression = a running internal combustion engine to...




GOOD fuel + spark+ compression= running internal combustion engine ;)



glad to hear it was an easy/ cheap fix. I love that kind of fix.
 
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