340 wont start

bass · Apr 13, 2018

need help
put in new points, condenser, plugs and wires, rotor cap and rotor, battery and cables. motor turns over good and white smoke from stack but not start. points set on .020 and plugs at .025.

fresh fuel, new sediment bowl and fuel lines and filter.

any comments or suggestions.

thanks
bass

AlinMO · Apr 13, 2018

Here is what Old has stated many times in previous posts:
"#1 check that you have a good blue white spark at the center wire of the distributor cap that will jump a 1/4 inch gap or more. Also do that at all 4 plug wires. If you do not have that check that the point have not slipped and or put the old condenser back in. Also with the point closed and the ignition on carefully open and close the points by hand. You should both see and hear a spark when you do that if no spark the points need to be cleaned. If you have that
#2 pull the carb drain plug and make sure you have a good steady flow of gas that will fill a pint jar in UNDER 3 minutes.
Post back what you find for more help"

hydro70guy · Apr 13, 2018

First 2 things are pull a plug and make sure you have good spark and check carb for fuel in the bowl. Also in making all these changes
make sure plug wires are in right order and correctly timed i.e. firing on the correct cylinder at correct time. That will find most likly
problem

Charlie M · Apr 13, 2018

If you have no spark and its 12 volts see if you have a resistor in line - could have gone bad. Was it running OK before you changed stuff?

gene bender · Apr 13, 2018

better start all over threw money for parts you didnt need. Do you have voltage to the coil. Then do you have
spark at the points then should have spark at the plugs. Now gas does gas runout with a good stream when you
remove the drain plug at the bottom of the carb. So if theres spark at the plugs and you have gas thru the carb
it will start and run.

old · Apr 13, 2018

You beat me to it LOL.

Only thing you forgot was the ask when the last time was that the air cleaner was serviced and the water and mud dumped out and fresh oil put in

old · Apr 13, 2018

Why all the parts??? Or are you trying to fix a no start problem with out trouble shooting first. If your trying to fix a no start you have most likely added to the problem by putting in new parts before trouble shooting.

Filter as in in line fuel filter if so good chance it is a big part of your problem and an in line filer does not work well on gravity flow system due to lack of fuel pressure.

I'd list my normal trouble shooting but AlinMO has done it already

bass · Apr 13, 2018

with yall's help here is where im at: checked coil wire for blue spark-- good spark. removed air cleaner-- it was full of real nasty rusty colored oil of some sort. no wires conected to dkey switch--replaced switch reconnected wires, now the lights work. cjecled points -- reset to 20/1000. good fuel flow thru carb

after all this the motor is now trying to back fire

so, this is where im at.

bass

Jim Becker · Apr 13, 2018

(quoted from post at 20:56:11 04/13/18 ). . . after all this the motor is now trying to back fire . . .

Crossed plug wires?

bass · Apr 14, 2018

plug wires in order 1 3 4 2

back firing, blowing gas out are cleaner hose... got air clear off right now
looks to be flooding

bass

old · Apr 14, 2018

Back fire is caused by one of 3 things. Carb running to lean. Timing off. Or a valve not closing as it should.

I would check that the points open the same at all 4 lobes. Distributor bushing getting bad will cause the points not to open as they should and cause a problem like your having.

Or a sticking valve or a valve not set right will also cause that problem.

Does choking hurt or help if it helps it is running to lean

bass · Apr 14, 2018

opening or closing choke has no effect

bass

old · Apr 14, 2018

If opening or closing the choke does nothing then are you sure there is a choke butterfly in the carb or the spring flap is missing. Closed should make the engine smoke and even die if warm. Open is how it should be when running and warm.

Weak spark will cause many odd problems and you need a good blue/white spark that will jump a 1/4 inch gap at all the plugs.

A couple years ago the 340 I have on the place started to run odd then would not run at all and I found the distributor drive gear had stripped out and would only spin some times which threw it off time etc.

MARK ROBKE · Apr 14, 2018

Was it running before you replaced these parts? If so,maybe you don't have #1 plug wire in the correct hole on the distributor cap? Or the order you put them on ,might be clockwise instead of counterclockwise wise.Then it would be flooded because you cranked it,but it couldn't fire at correct time.Mark.

bass · Apr 14, 2018

up date:

getting spark only on #1 plug. pulled the rotor and cap. shaft is turning and points are opening and closing. gap on all lobes is .020"

any ideas?

bass

340 wont start

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