WILL NOT START, SPITS OUT CARB, WE HAVE GOOD SPARK, LEAK DOWN TEST YEILDED POR RESULTS. GOOD COMPRESSION 175 LBS , THINKING ELECTRONC NEEDLE VALVE MAY NOT BE FUNCTIONING CORRECTLY / NEED SOME TYPE OF DIAGNOSTIC MANUAL
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Re: WONT START GOOD SPARK SPITS OUT OF CARB
This problem can't be the anti-diesel solenoid in the carb, that only does anything when the engine is shutting down. Because you got poor results in the leakdown test and get 175 psi of compression (way too much), I suspect that either your intake valve is bad or misadjusted, or the key that holds the flywheel to the crankshaft is sheared off. Check the valve lash settings and visually inspect the operation ov the valves while you're setting them. If the valves are OK remove the flywheel and check the key.
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check spark plugs if electrode full of oil more likely valve seals and valve guides worn.if you see white smoke new head gasket leaking do a compression test see what cylinder pressure you have.you need at least 140 to 175 compression.
any compression difference of 20 lbs or more is a serious problem. you seem like a logical fellow, so where would such a compression loss occur? rings, gasket, or valves. the standard way to find out where compression is leaking is called a wet/dry compression test. first you take readings the standard way and write them down. then you squirt a little oil into the cylinders one by one and test them again. if the compression goes up by more than 20 lbs., then the rings are the problem. if the reading stays the same as the first time then it is valves. tell that to the multiple people.
you need to do a cylinder leak down test. That will tell you if it is a valve, which one or if it is rings. Try a compression test too. 5 pulls should be 160 to 190 ish. If all that is ok check the carb to see why it is causing a rich running scenario
30 PSI IS NOT GOOD AT ALL. YOU NEED TO DO A LEAK DOWN TEST ON THE MACHINE TO DETERMINE WHERE YOU ARE LOSING COMPRESSION. IT COULD BE AS EASY AS A VALVE ADJUSTMENT OR IT COULD BE A BAD RING. YOU WILL BE ABLE TO HEAR WHERE THE LEAK IS BY LISTENING TO THE EXHAUST, CARB AND REMOVE THE OIL FILL PLUG AND YOU CAN FEEL THE AIR LEAKING . THE CARB OR EXHAUST IS MORE THAN LIKELY A VALVE PROBLEM POSSIBLY JUST ADJUSTMENT,. AIR FROM CRANKCASE IS RINGS.
You need 3 things.
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.
You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel. Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by
plugging return line or just or the true full pressure can be taken
direct at the end fuel filter.
What are the pressure readings that you have when done.
What are your cold start pressure readings?
Post back what you have. Good luck
If three of the four spark plugs are firing good you can eliminate the coils. Most likely if only one plug is fouling with oil it is a leaking valve seal or a broken ring. To determine which is the problem, remove all four spark plugs and complete a compression test of each cylinder. Write down the results to compare with the next step. Each cylinder should be within ten percent of the others, Now, squirt about a tablespoon amount of oil in each cylinder. If there was low compression on the #2 cylinder and the compression increases substantially with the oil inserted you have a broken ring. If there is low to no compression on the #2 cylinder you have a burnt valve. If the compression does not increase and the spark plug fouls with oil you have a bad valve stem seal.
Install a new stock spark plug after getting the compression checked and the valve clearances checked. Assuming good compression, use the choke when cold starting but don't flood the engine. Clean the air filter? If, when running, the bike dies when the throttle is turned, remove the jet needle from the throat of the carb and move the clip on the needle down one, possibly two, notches. This will richen the low end mix.